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Duraisamy AJ, Liu R, Sureshkumar S, Rose R, Jagannathan L, da Silva C, Coovadia A, Ramachander V, Chandrasekar S, Raja I, Sajnani M, Selvaraj SM, Narang B, Darvishi K, Bhayal AC, Katikala L, Guo F, Chen-Deutsch X, Balciuniene J, Ma Z, Nallamilli BRR, Bean L, Collins C, Hegde M. Focused Exome Sequencing Gives a High Diagnostic Yield in the Indian Subcontinent. J Mol Diagn 2024; 26:510-519. [PMID: 38582400 DOI: 10.1016/j.jmoldx.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 09/11/2023] [Accepted: 03/01/2024] [Indexed: 04/08/2024] Open
Abstract
The genetically isolated yet heterogeneous and highly consanguineous Indian population has shown a higher prevalence of rare genetic disorders. However, there is a significant socioeconomic burden for genetic testing to be accessible to the general population. In the current study, we analyzed next-generation sequencing data generated through focused exome sequencing from individuals with different phenotypic manifestations referred for genetic testing to achieve a molecular diagnosis. Pathogenic or likely pathogenic variants are reported in 280 of 833 cases with a diagnostic yield of 33.6%. Homozygous sequence and copy number variants were found as positive diagnostic findings in 131 cases (15.7%) because of the high consanguinity in the Indian population. No relevant findings related to reported phenotype were identified in 6.2% of the cases. Patients referred for testing due to metabolic disorder and neuromuscular disorder had higher diagnostic yields. Carrier testing of asymptomatic individuals with a family history of the disease, through focused exome sequencing, achieved positive diagnosis in 54 of 118 cases tested. Copy number variants were also found in trans with single-nucleotide variants and mitochondrial variants in a few of the cases. The diagnostic yield and the findings from this study signify that a focused exome test is a good lower-cost alternative for whole-exome and whole-genome sequencing and as a first-tier approach to genetic testing.
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Affiliation(s)
| | - Ruby Liu
- Revvity Omics, Pittsburgh, Pennsylvania
| | | | - Rajiv Rose
- PerkinElmer Genomics, Revvity Omics, Chennai, India
| | | | | | | | | | | | - Indu Raja
- PerkinElmer Genomics, Revvity Omics, Chennai, India
| | | | | | | | | | | | | | - Fen Guo
- Revvity Omics, Pittsburgh, Pennsylvania
| | | | | | | | | | - Lora Bean
- Revvity Omics, Pittsburgh, Pennsylvania
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2
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Olimpio C, Paramonov I, Matalonga L, Laurie S, Schon K, Polavarapu K, Kirschner J, Schara-Schmidt U, Lochmüller H, Chinnery PF, Horvath R. Increased Diagnostic Yield by Reanalysis of Whole Exome Sequencing Data in Mitochondrial Disease. J Neuromuscul Dis 2024:JND240020. [PMID: 38759022 DOI: 10.3233/jnd-240020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2024]
Abstract
Background The genetic diagnosis of mitochondrial disorders is complicated by its genetic and phenotypic complexity. Next generation sequencing techniques have much improved the diagnostic yield for these conditions. A cohort of individuals with multiple respiratory chain deficiencies, reported in the literature 10 years ago, had a diagnostic rate of 60% by whole exome sequencing (WES) but 40% remained undiagnosed. Objective We aimed to identify a genetic diagnosis by reanalysis of the WES data for the undiagnosed arm of this 10-year-old cohort of patients with suspected mitochondrial disorders. Methods The WES data was transferred and processed by the RD-Connect Genome-Phenome Analysis Platform (GPAP) using their standardized pipeline. Variant prioritisation was carried out on the RD-Connect GPAP. Results Singleton WES data from 14 individuals was reanalysed. We identified a possible or likely genetic diagnosis in 8 patients (8/14, 57%). The variants identified were in a combination of mitochondrial DNA (n = 1, MT-TN), nuclear encoded mitochondrial genes (n = 2, PDHA1, and SUCLA2) and nuclear genes associated with nonmitochondrial disorders (n = 5, PNPLA2, CDC40, NBAS and SLC7A7). Variants in both the NBAS and CDC40 genes were established as disease causing after the original cohort was published. We increased the diagnostic yield for the original cohort by 15% without generating any further genomic data. CONCLUSIONS In the era of multiomics we highlight that reanalysis of existing WES data is a valid tool for generating additional diagnosis in patients with suspected mitochondrial disease, particularly when more time has passed to allow for new bioinformatic pipelines to emerge, for the development of new tools in variant interpretation aiding in reclassification of variants and the expansion of scientific knowledge on additional genes.
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Affiliation(s)
- Catarina Olimpio
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, CB2 0PY Cambridge, UK
- East Anglian Medical Genetics Service, Cambridge University Hospitals NHS Foundation Trust, Cambridge, CB2 0QQ Cambridge United Kingdom
| | - Ida Paramonov
- Centro Nacional de Análisis Genómico, C/Baldiri Reixac 4, 08028 Barcelona, Spain
| | - Leslie Matalonga
- Centro Nacional de Análisis Genómico, C/Baldiri Reixac 4, 08028 Barcelona, Spain
| | - Steven Laurie
- Centro Nacional de Análisis Genómico, C/Baldiri Reixac 4, 08028 Barcelona, Spain
| | - Katherine Schon
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, CB2 0PY Cambridge, UK
- East Anglian Medical Genetics Service, Cambridge University Hospitals NHS Foundation Trust, Cambridge, CB2 0QQ Cambridge United Kingdom
| | - Kiran Polavarapu
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON K1H 8M5, Canada
| | - Janbernd Kirschner
- Department of Neuropediatrics and Muscle Disorders, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg 79110, Germany
| | - Ulrike Schara-Schmidt
- Department of Pediatric Neurology, Center for Neuromuscular Disorders, Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, Hufelandstr. 55, Essen 45147, Germany
| | - Hanns Lochmüller
- Centro Nacional de Análisis Genómico, C/Baldiri Reixac 4, 08028 Barcelona, Spain
- Department of Neuropediatrics and Muscle Disorders, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg 79110, Germany
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON K1H 8M5, Canada
| | - Patrick F Chinnery
- MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Rita Horvath
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, CB2 0PY Cambridge, UK
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Rouzier C, Pion E, Chaussenot A, Bris C, Ait-El-Mkadem Saadi S, Desquiret-Dumas V, Gueguen N, Fragaki K, Amati-Bonneau P, Barcia G, Gaignard P, Steffann J, Pennisi A, Bonnefont JP, Lebigot E, Bannwarth S, Francou B, Rucheton B, Sternberg D, Martin-Negrier ML, Trimouille A, Hardy G, Allouche S, Acquaviva-Bourdain C, Pagan C, Lebre AS, Reynier P, Cossee M, Attarian S, Paquis-Flucklinger V, Procaccio V. Primary mitochondrial disorders and mimics: Insights from a large French cohort. Ann Clin Transl Neurol 2024. [PMID: 38703036 DOI: 10.1002/acn3.52062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 03/23/2024] [Indexed: 05/06/2024] Open
Abstract
OBJECTIVE The objective of this study was to evaluate the implementation of NGS within the French mitochondrial network, MitoDiag, from targeted gene panels to whole exome sequencing (WES) or whole genome sequencing (WGS) focusing on mitochondrial nuclear-encoded genes. METHODS Over 2000 patients suspected of Primary Mitochondrial Diseases (PMD) were sequenced by either targeted gene panels, WES or WGS within MitoDiag. We described the clinical, biochemical, and molecular data of 397 genetically confirmed patients, comprising 294 children and 103 adults, carrying pathogenic or likely pathogenic variants in nuclear-encoded genes. RESULTS The cohort exhibited a large genetic heterogeneity, with the identification of 172 distinct genes and 253 novel variants. Among children, a notable prevalence of pathogenic variants in genes associated with oxidative phosphorylation (OXPHOS) functions and mitochondrial translation was observed. In adults, pathogenic variants were primarily identified in genes linked to mtDNA maintenance. Additionally, a substantial proportion of patients (54% (42/78) and 48% (13/27) in children and adults, respectively), undergoing WES or WGS testing displayed PMD mimics, representing pathologies that clinically resemble mitochondrial diseases. INTERPRETATION We reported the largest French cohort of patients suspected of PMD with pathogenic variants in nuclear genes. We have emphasized the clinical complexity of PMD and the challenges associated with recognizing and distinguishing them from other pathologies, particularly neuromuscular disorders. We confirmed that WES/WGS, instead of panel approach, was more valuable to identify the genetic basis in patients with "possible" PMD and we provided a genetic testing flowchart to guide physicians in their diagnostic strategy.
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Affiliation(s)
- Cécile Rouzier
- Service de génétique médicale, Centre de référence des maladies mitochondriales, CHU Nice, Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | - Emmanuelle Pion
- Filnemus, laboratoire de génétique moléculaire, CHU, Montpellier, France
| | - Annabelle Chaussenot
- Service de génétique médicale, Centre de référence des maladies mitochondriales, CHU Nice, Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | - Céline Bris
- Service de génétique, Institut de Biologie en santé, CHU Angers, Univ Angers, INSERM, CNRS, MITOVASC, Equipe MitoLab, SFR ICAT, Angers, France
| | - Samira Ait-El-Mkadem Saadi
- Service de génétique médicale, Centre de référence des maladies mitochondriales, CHU Nice, Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | - Valérie Desquiret-Dumas
- Service de biochimie et biologie moléculaire, Institut de Biologie en santé, CHU Angers, Univ Angers, INSERM, CNRS, MITOVASC, Equipe MitoLab, SFR ICAT, Angers, France
| | - Naïg Gueguen
- Service de biochimie et biologie moléculaire, Institut de Biologie en santé, CHU Angers, Univ Angers, INSERM, CNRS, MITOVASC, Equipe MitoLab, SFR ICAT, Angers, France
| | - Konstantina Fragaki
- Service de génétique médicale, Centre de référence des maladies mitochondriales, CHU Nice, Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | - Patrizia Amati-Bonneau
- Service de biochimie et biologie moléculaire, Institut de Biologie en santé, CHU Angers, Univ Angers, INSERM, CNRS, MITOVASC, Equipe MitoLab, SFR ICAT, Angers, France
| | - Giulia Barcia
- Service de médecine génomique des maladies rares, Hôpital Necker-Enfants Malades, Université Paris Cité, Institut Imagine Unité UMR 1161, Paris, France
| | - Pauline Gaignard
- Service de Biochimie, GHU APHP Paris Saclay, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Julie Steffann
- Service de médecine génomique des maladies rares, Hôpital Necker-Enfants Malades, Université Paris Cité, Institut Imagine Unité UMR 1161, Paris, France
| | - Alessandra Pennisi
- Service de médecine génomique des maladies rares, Hôpital Necker-Enfants Malades, Université Paris Cité, Institut Imagine Unité UMR 1161, Paris, France
| | - Jean-Paul Bonnefont
- Service de médecine génomique des maladies rares, Hôpital Necker-Enfants Malades, Université Paris Cité, Institut Imagine Unité UMR 1161, Paris, France
| | - Elise Lebigot
- Service de Biochimie, GHU APHP Paris Saclay, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Sylvie Bannwarth
- Service de génétique médicale, Centre de référence des maladies mitochondriales, CHU Nice, Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | - Bruno Francou
- Service de génétique médicale, Centre de référence des maladies mitochondriales, CHU Nice, Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | | | - Damien Sternberg
- Unité Fonctionnelle de cardiogénétique et myogénétique moléculaire et cellulaire, Centre de génétique moléculaire et chromosomique, AP-HP Sorbonne Université, Hopital de la Pitié-Salpêtrière, Paris, France
| | - Marie-Laure Martin-Negrier
- Unité fonctionnelle d'histologie moléculaire, Service de pathologie, CHU Bordeaux-GU Pellegrin, Bordeaux, France
| | - Aurélien Trimouille
- Unité fonctionnelle d'histologie moléculaire, Service de pathologie, CHU Bordeaux-GU Pellegrin, Bordeaux, France
| | - Gaëlle Hardy
- Laboratoire de Génétique Moléculaire: Maladies Héréditaires et Oncologie, Institut de Biologie et de Pathologie, CHU Grenoble Alpes, Grenoble, France
| | - Stéphane Allouche
- Service de biochimie, Institut Territorial de Biologie en Santé, CHU Caen, Hôpital de la Côte de Nacre, Caen, France
| | - Cécile Acquaviva-Bourdain
- Service de biochimie et biologie moléculaire Grand Est, UM Maladies Héréditaires du Métabolisme, Centre de biologie et pathologie Est, CHU Lyon HCL, GH Est, Lyon, France
| | - Cécile Pagan
- Service de biochimie et biologie moléculaire Grand Est, UM Maladies Héréditaires du Métabolisme, Centre de biologie et pathologie Est, CHU Lyon HCL, GH Est, Lyon, France
| | - Anne-Sophie Lebre
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266 [Krebs team], Université de Reims Champagne-Ardenne (UFR médicale) - CHU de Reims-Université Paris Cité, Paris, France
| | - Pascal Reynier
- Service de biochimie et biologie moléculaire, Institut de Biologie en santé, CHU Angers, Univ Angers, INSERM, CNRS, MITOVASC, Equipe MitoLab, SFR ICAT, Angers, France
| | - Mireille Cossee
- Laboratoire de Génétique Moléculaire, CHU Montpellier, PhyMedExp, Université de Montpellier, INSERM, CNRS, Montpellier, France
| | - Shahram Attarian
- Service des Maladies Neuromusculaires et la SLA, FILNEMUS, Euro-NMDAIX-CHU La Timone, Marseille Université, Marseille, France
| | - Véronique Paquis-Flucklinger
- Service de génétique médicale, Centre de référence des maladies mitochondriales, CHU Nice, Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | - Vincent Procaccio
- Service de génétique, Institut de Biologie en santé, CHU Angers, Univ Angers, INSERM, CNRS, MITOVASC, Equipe MitoLab, SFR ICAT, Angers, France
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4
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Pettenuzzo I, Carli S, Sánchez-Cuesta A, Isidori F, Montanari F, Grippa M, Lanzoni G, Ambrosetti I, Di Pisa V, Cordelli DM, Mondardini MC, Pippucci T, Ragni L, Cenacchi G, Costa R, Lima M, Capristo MA, Tropeano CV, Caporali L, Carelli V, Brunelli E, Maffei M, Ahmed Sheikhmaye H, Fetta A, Brea-Calvo G, Garone C. COQ7 defect causes prenatal onset of mitochondrial CoQ 10 deficiency with cardiomyopathy and gastrointestinal obstruction. Eur J Hum Genet 2024:10.1038/s41431-024-01615-w. [PMID: 38702428 DOI: 10.1038/s41431-024-01615-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/22/2024] [Accepted: 04/17/2024] [Indexed: 05/06/2024] Open
Abstract
COQ7 pathogenetic variants cause primary CoQ10 deficiency and a clinical phenotype of encephalopathy, peripheral neuropathy, or multisystemic disorder. Early diagnosis is essential for promptly starting CoQ10 supplementation. Here, we report novel compound heterozygous variants in the COQ7 gene responsible for a prenatal onset (20 weeks of gestation) of hypertrophic cardiomyopathy and intestinal dysmotility in a Bangladesh consanguineous family with two affected siblings. The main clinical findings were dysmorphisms, recurrent intestinal occlusions that required ileostomy, left ventricular non-compaction cardiomyopathy, ascending aorta dilation, arterial hypertension, renal dysfunction, diffuse skin desquamation, axial hypotonia, neurodevelopmental delay, and growth retardation. Exome sequencing revealed compound heterozygous rare variants in the COQ7 gene, c.613_617delGCCGGinsCAT (p.Ala205HisfsTer48) and c.403A>G (p.Met135Val). In silico analysis and functional in vitro studies confirmed the pathogenicity of the variants responsible for abolished activities of complexes I + III and II + III in muscle homogenate, severe decrease of CoQ10 levels, and reduced basal and maximal respiration in patients' fibroblasts. The first proband deceased at 14 months of age, whereas supplementation with a high dose of CoQ10 (30 mg/kg/day) since the first days of life modified the clinical course in the second child, showing a recovery of milestones acquirement at the last follow-up (18 months of age). Our study expands the clinical spectrum of primary CoQ10 deficiency due to COQ7 gene defects and highlights the essential role of multidisciplinary and combined approaches for a timely diagnosis.
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Affiliation(s)
- Ilaria Pettenuzzo
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'età Pediatrica, Bologna, Italy
| | - Sara Carli
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138, Bologna, Italy
- Center for Applied Biomedical Research, Alma Mater Studiorum, University of Bologna, 40138, Bologna, Italy
| | - Ana Sánchez-Cuesta
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA and CIBERER, Instituto de Salud Carlos III, Seville, 41013, Spain
| | - Federica Isidori
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138, Bologna, Italy
| | - Francesca Montanari
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138, Bologna, Italy
| | - Mina Grippa
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138, Bologna, Italy
| | - Giulia Lanzoni
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138, Bologna, Italy
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138, Bologna, Italy
| | - Irene Ambrosetti
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138, Bologna, Italy
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138, Bologna, Italy
| | - Veronica Di Pisa
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'età Pediatrica, Bologna, Italy
| | - Duccio Maria Cordelli
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'età Pediatrica, Bologna, Italy
| | - Maria Cristina Mondardini
- Pediatric Anesthesia and Intensive Care Unit, Department of Woman's and Child's Health, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Tommaso Pippucci
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40138, Bologna, Italy
| | - Luca Ragni
- Pediatric Cardiology and Adult Congenital Heart Disease Program, Department of Cardio-Thoracic and Vascular Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Giovanna Cenacchi
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Roberta Costa
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Mario Lima
- Pediatric Surgery Department, IRCCS Sant'Orsola-Malpighi Polyclinic, Alma Mater Studiorum-University of Bologna, 40126, Bologna, Italy
| | | | | | - Leonardo Caporali
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum University of Bologna, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Valerio Carelli
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum University of Bologna, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Elena Brunelli
- Obstetric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna University of Bologna, Bologna, Italia
| | - Monica Maffei
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di neuroradiologia con tecniche ad elevata complessità, Bologna, Italia
| | - Hodman Ahmed Sheikhmaye
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di neuroradiologia con tecniche ad elevata complessità, Bologna, Italia
| | - Anna Fetta
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'età Pediatrica, Bologna, Italy
| | - Gloria Brea-Calvo
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-CSIC-JA and CIBERER, Instituto de Salud Carlos III, Seville, 41013, Spain
| | - Caterina Garone
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40138, Bologna, Italy.
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'età Pediatrica, Bologna, Italy.
- Center for Applied Biomedical Research, Alma Mater Studiorum, University of Bologna, 40138, Bologna, Italy.
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Disha B, Mathew RP, Dalal AB, Mahato AK, Satyamoorthy K, Singh KK, Thangaraj K, Govindaraj P. Mitochondria in biology and medicine - 2023. Mitochondrion 2024; 76:101853. [PMID: 38423268 DOI: 10.1016/j.mito.2024.101853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/07/2024] [Accepted: 02/14/2024] [Indexed: 03/02/2024]
Abstract
Mitochondria are an indispensable part of the cell that plays a crucial role in regulating various signaling pathways, energy metabolism, cell differentiation, proliferation, and cell death. Since mitochondria have their own genetic material, they differ from their nuclear counterparts, and dysregulation is responsible for a broad spectrum of diseases. Mitochondrial dysfunction is associated with several disorders, including neuro-muscular disorders, cancer, and premature aging, among others. The intricacy of the field is due to the cross-talk between nuclear and mitochondrial genes, which has also improved our knowledge of mitochondrial functions and their pathogenesis. Therefore, interdisciplinary research and communication are crucial for mitochondrial biology and medicine due to the challenges they pose for diagnosis and treatment. The ninth annual conference of the Society for Mitochondria Research and Medicine (SMRM)- India, titled "Mitochondria in Biology and Medicine" was organized at the Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India, on June 21-23, 2023. The latest advancements in the field of mitochondrial biology and medicine were discussed at the conference. In this article, we summarize the entire event for the benefit of researchers working in the field of mitochondrial biology and medicine.
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Affiliation(s)
- B Disha
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India; Regional Centre for Biotechnology, Faridabad, Haryana 121001, India
| | - Rohan Peter Mathew
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India; Manipal Academy of Higher Education, Manipal 576104, India
| | - Ashwin B Dalal
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India
| | - Ajay K Mahato
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India
| | - Kapaettu Satyamoorthy
- Shri Dharmasthala Manjunatheshwara (SDM) University, SDM College of Medical Sciences and Hospital, Manjushree Nagar, Sattur, Dharwad 580009, India
| | - Keshav K Singh
- Department of Genetics, School of Medicine, The University of Alabama at Birmingham, Kaul Genetics Building, Rm. 620, 720 20th St. South, Birmingham, AL, 35294, USA
| | - Kumarasamy Thangaraj
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | - Periyasamy Govindaraj
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad 500039, India; Department of Neuropathology, National Institute of Mental Health and Neurosciences, Hosur Road, Bengaluru 560029, India.
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6
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Baker ZN, Forny P, Pagliarini DJ. Mitochondrial proteome research: the road ahead. Nat Rev Mol Cell Biol 2024; 25:65-82. [PMID: 37773518 DOI: 10.1038/s41580-023-00650-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2023] [Indexed: 10/01/2023]
Abstract
Mitochondria are multifaceted organelles with key roles in anabolic and catabolic metabolism, bioenergetics, cellular signalling and nutrient sensing, and programmed cell death processes. Their diverse functions are enabled by a sophisticated set of protein components encoded by the nuclear and mitochondrial genomes. The extent and complexity of the mitochondrial proteome remained unclear for decades. This began to change 20 years ago when, driven by the emergence of mass spectrometry-based proteomics, the first draft mitochondrial proteomes were established. In the ensuing decades, further technological and computational advances helped to refine these 'maps', with current estimates of the core mammalian mitochondrial proteome ranging from 1,000 to 1,500 proteins. The creation of these compendia provided a systemic view of an organelle previously studied primarily in a reductionist fashion and has accelerated both basic scientific discovery and the diagnosis and treatment of human disease. Yet numerous challenges remain in understanding mitochondrial biology and translating this knowledge into the medical context. In this Roadmap, we propose a path forward for refining the mitochondrial protein map to enhance its discovery and therapeutic potential. We discuss how emerging technologies can assist the detection of new mitochondrial proteins, reveal their patterns of expression across diverse tissues and cell types, and provide key information on proteoforms. We highlight the power of an enhanced map for systematically defining the functions of its members. Finally, we examine the utility of an expanded, functionally annotated mitochondrial proteome in a translational setting for aiding both diagnosis of mitochondrial disease and targeting of mitochondria for treatment.
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Affiliation(s)
- Zakery N Baker
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Patrick Forny
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
| | - David J Pagliarini
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA.
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7
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Chen PS, Lee NC, Sung CJ, Liu YW, Weng WC, Fan PC, Lee WT, Chien YH, Wu CS, Sung YF, Tsai MC, Lee YC, Hsueh HW, Fan SMY, Wu MC, Li H, Chen HY, Lin HI, Ou-Yang CH, Hwuh WL, Lin CH. Phenotypic Heterogeneity in Patients with Mutations in the Mitochondrial Complex I Assembly Gene NDUFAF5. Mov Disord 2023; 38:2217-2229. [PMID: 37752895 DOI: 10.1002/mds.29604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/15/2023] [Accepted: 08/29/2023] [Indexed: 09/28/2023] Open
Abstract
BACKGROUND Rare mutations in NADH:ubiquinone oxidoreductase complex assembly factor 5 (NDUFAF5) are linked to Leigh syndrome. OBJECTIVE We aimed to describe clinical characteristics and functional findings in a patient cohort with NDUFAF5 mutations. METHODS Patients with biallelic NDUFAF5 mutations were recruited from multi-centers in Taiwan. Clinical, laboratory, radiological, and follow-up features were recorded and mitochondrial assays were performed in patients' skin fibroblasts. RESULTS Nine patients from seven unrelated pedigrees were enrolled, eight homozygous for c.836 T > G (p.Met279Arg) in NDUFAF5 and one compound heterozygous for p.Met279Arg. Onset age had a bimodal distribution. The early-onset group (age <3 years) presented with psychomotor delay, seizure, respiratory failure, and hyponatremia. The late-onset group (age ≥5 years) presented with normal development, but slowly progressive dystonia. Combing 25 previously described patients, the p.Met279Arg variant was exclusively identified in Chinese ancestry. Compared with other groups, patients with late-onset homozygous p.Met279Arg were older at onset (P = 0.008), had less developmental delay (P = 0.01), less hyponatremia (P = 0.01), and better prognosis with preserved ambulatory function into early adulthood (P = 0.01). Bilateral basal ganglia necrosis was a common radiological feature, but brainstem and spinal cord involvement was more common with early-onset patients (P = 0.02). A modifier gene analysis showed higher concomitant mutation burden in early-versus late-onset p.Met279Arg homozygous cases (P = 0.04), consistent with more impaired mitochondrial function in fibroblasts from an early-onset case than a late-onset patient. CONCLUSIONS The p.Met279Arg variant is a common mutation in our population with phenotypic heterogeneity and divergent prognosis based on age at onset. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Pin-Shiuan Chen
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Ni-Chung Lee
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
- Department of Pediatrics, National Taiwan University Children's Hospital, Taipei, Taiwan
| | - Chieh-Ju Sung
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ya-Wen Liu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wen-Chin Weng
- Department of Pediatrics, National Taiwan University Children's Hospital, Taipei, Taiwan
| | - Pi-Chuan Fan
- Department of Pediatrics, National Taiwan University Children's Hospital, Taipei, Taiwan
| | - Wang-Tso Lee
- Department of Pediatrics, National Taiwan University Children's Hospital, Taipei, Taiwan
| | - Yin-Hsiu Chien
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
- Department of Pediatrics, National Taiwan University Children's Hospital, Taipei, Taiwan
| | - Chao-Szu Wu
- Department of Pediatrics, National Taiwan University Children's Hospital, Taipei, Taiwan
| | - Yueh-Feng Sung
- Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Ming-Chen Tsai
- Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Yi-Chung Lee
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Hsueh-Wen Hsueh
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Sabrina Mai-Yi Fan
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Meng-Chen Wu
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Geriatrics and Gerontology, National Taiwan University Hospital, Taipei, Taiwan
| | - Hsun Li
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Huan-Yun Chen
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Han-I Lin
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Chih-Hsin Ou-Yang
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Wuh-Liang Hwuh
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
- Department of Pediatrics, National Taiwan University Children's Hospital, Taipei, Taiwan
| | - Chin-Hsien Lin
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
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8
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Serag M, Plutino M, Charles P, Azulay JP, Chaussenot A, Paquis-Flucklinger V, Ait-El-Mkadem Saadi S, Rouzier C. A Case Report of SYNE1 Deficiency-Mimicking Mitochondrial Disease and the Value of Pangenomic Investigations. Genes (Basel) 2023; 14:2154. [PMID: 38136976 PMCID: PMC10743207 DOI: 10.3390/genes14122154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 11/24/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023] Open
Abstract
Mitochondrial disorders are characterized by a huge clinical, biochemical, and genetic heterogeneity, which poses significant diagnostic challenges. Several studies report that more than 50% of patients with suspected mitochondrial disease could have a non-mitochondrial disorder. Thus, only the identification of the causative pathogenic variant can confirm the diagnosis. Herein, we describe the diagnostic journey of a family suspected of having a mitochondrial disorder who were referred to our Genetics Department. The proband presented with the association of cerebellar ataxia, COX-negative fibers on muscle histology, and mtDNA deletions. Whole exome sequencing (WES), supplemented by a high-resolution array, comparative genomic hybridization (array-CGH), allowed us to identify two pathogenic variants in the non-mitochondrial SYNE1 gene. The proband and her affected sister were found to be compound heterozygous for a known nonsense variant (c.13258C>T, p.(Arg4420Ter)), and a large intragenic deletion that was predicted to result in a loss of function. To our knowledge, this is the first report of a large intragenic deletion of SYNE1 in patients with cerebellar ataxia (ARCA1). This report highlights the interest in a pangenomic approach to identify the genetic basis in heterogeneous neuromuscular patients with the possible cause of mitochondrial disease. Moreover, even rare copy number variations should be considered in patients with a phenotype suggestive of SYNE1 deficiency.
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Affiliation(s)
- Mounir Serag
- Service de Génétique Médicale, Hôpital l’Archet 2, CHU de Nice, 151 Route Saint-Antoine de Ginestière, 06202 Nice, France; (M.S.); (M.P.); (A.C.); (V.P.-F.); (S.A.-E.-M.S.)
- CNRS UMR7284/ INSERM U1081, Faculté de Médecine, Université Côte d’Azur, 06107 Nice, France
| | - Morgane Plutino
- Service de Génétique Médicale, Hôpital l’Archet 2, CHU de Nice, 151 Route Saint-Antoine de Ginestière, 06202 Nice, France; (M.S.); (M.P.); (A.C.); (V.P.-F.); (S.A.-E.-M.S.)
- CNRS UMR7284/ INSERM U1081, Faculté de Médecine, Université Côte d’Azur, 06107 Nice, France
| | - Perrine Charles
- Service de Génétique, La Pitié-Salpêtrière, AP-HP, 75610 Paris, France;
| | | | - Annabelle Chaussenot
- Service de Génétique Médicale, Hôpital l’Archet 2, CHU de Nice, 151 Route Saint-Antoine de Ginestière, 06202 Nice, France; (M.S.); (M.P.); (A.C.); (V.P.-F.); (S.A.-E.-M.S.)
- CNRS UMR7284/ INSERM U1081, Faculté de Médecine, Université Côte d’Azur, 06107 Nice, France
| | - Véronique Paquis-Flucklinger
- Service de Génétique Médicale, Hôpital l’Archet 2, CHU de Nice, 151 Route Saint-Antoine de Ginestière, 06202 Nice, France; (M.S.); (M.P.); (A.C.); (V.P.-F.); (S.A.-E.-M.S.)
- CNRS UMR7284/ INSERM U1081, Faculté de Médecine, Université Côte d’Azur, 06107 Nice, France
| | - Samira Ait-El-Mkadem Saadi
- Service de Génétique Médicale, Hôpital l’Archet 2, CHU de Nice, 151 Route Saint-Antoine de Ginestière, 06202 Nice, France; (M.S.); (M.P.); (A.C.); (V.P.-F.); (S.A.-E.-M.S.)
- CNRS UMR7284/ INSERM U1081, Faculté de Médecine, Université Côte d’Azur, 06107 Nice, France
| | - Cécile Rouzier
- Service de Génétique Médicale, Hôpital l’Archet 2, CHU de Nice, 151 Route Saint-Antoine de Ginestière, 06202 Nice, France; (M.S.); (M.P.); (A.C.); (V.P.-F.); (S.A.-E.-M.S.)
- CNRS UMR7284/ INSERM U1081, Faculté de Médecine, Université Côte d’Azur, 06107 Nice, France
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9
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Murgia C, Dehlia A, Guthridge MA. New insights into the nutritional genomics of adult-onset riboflavin-responsive diseases. Nutr Metab (Lond) 2023; 20:42. [PMID: 37845732 PMCID: PMC10580530 DOI: 10.1186/s12986-023-00764-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 10/04/2023] [Indexed: 10/18/2023] Open
Abstract
Riboflavin, or vitamin B2, is an essential nutrient that serves as a precursor to flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN). The binding of the FAD and/or FMN cofactors to flavoproteins is critical for regulating their assembly and activity. There are over 90 proteins in the human flavoproteome that regulate a diverse array of biochemical pathways including mitochondrial metabolism, riboflavin transport, ubiquinone and FAD synthesis, antioxidant signalling, one-carbon metabolism, nitric oxide signalling and peroxisome oxidative metabolism. The identification of patients with genetic variants in flavoprotein genes that lead to adult-onset pathologies remains a major diagnostic challenge. However, once identified, many patients with adult-onset inborn errors of metabolism demonstrate remarkable responses to riboflavin therapy. We review the structure:function relationships of mutant flavoproteins and propose new mechanistic insights into adult-onset riboflavin-responsive pathologies and metabolic dysregulations that apply to multiple biochemical pathways. We further address the vexing issue of how the inheritance of genetic variants in flavoprotein genes leads to an adult-onset disease with complex symptomologies and varying severities. We also propose a broad clinical framework that may not only improve the current diagnostic rates, but also facilitate a personalized approach to riboflavin therapy that is low cost, safe and lead to transformative outcomes in many patients.
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Affiliation(s)
- Chiara Murgia
- The School of Agriculture, Food and Ecosystem Sciences (SAFES), Faculty of Science, The University of Melbourne, Parkville, Australia.
| | - Ankush Dehlia
- School of Life and Environmental Sciences, Deakin University, Burwood, Australia
| | - Mark A Guthridge
- School of Life and Environmental Sciences, Deakin University, Burwood, Australia
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10
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Petrović Pajić S, Suštar Habjan M, Brecelj J, Fakin A, Volk M, Maver A, Jezernik G, Peterlin B, Glavač D, Hawlina M, Jarc-Vidmar M. Leber Hereditary Optic Neuropathy in a Family of Carriers of MT-ND5 m.13042G>T (A236S) Novel Variant. J Neuroophthalmol 2023; 43:341-347. [PMID: 36897664 DOI: 10.1097/wno.0000000000001820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
BACKGROUND A Slovenian three-generation family with 3 individuals with bilateral optic neuropathy and 2 unaffected relatives with a novel homoplasmic missense variant m.13042G > T (A236S) in the ND5 gene is described. A detailed phenotype at initial diagnosis and a follow-up of bilateral optic neuropathy progression is presented for 2 affected individuals. METHODS A detailed phenotype analysis with clinical examination in the early and chronic phase with electrophysiology and OCT segmentation is presented. Genotype analysis with full mitochondrial genome sequencing was performed. RESULTS Two affected male individuals (maternal cousins) had a profound visual loss at an early age (11 and 20 years) with no recovery. The maternal grandmother exhibited bilateral optic atrophy with a history of visual loss at the age 58 years. The visual loss of both affected male individuals was characterized by centrocecal scotoma, abnormal color vision, abnormal PERG N95, and VEP. Later with disease progression, retinal nerve fiber layer thinning was observed on OCT. We observed no other extraocular clinical features. Mitochondrial sequencing identified a homoplasmic novel variant m.13042G > T (A236S) in the MT-ND5 gene, belonging to a haplogroup K1a. CONCLUSIONS Novel homoplasmic variant m.13042G > T (A236S) in the ND5 gene in our family was associated with Leber hereditary optic neuropathy-like phenotype. However, predicting the pathogenicity of a novel ultra-rare missense variant in the mitochondrial ND5 gene is challenging. Genetic counseling should consider genotypic and phenotypic heterogeneity, incomplete penetrance, haplogroup type, and tissue-specific thresholds.
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Affiliation(s)
- Sanja Petrović Pajić
- Eye Hospital (SPP, MJV, BSK, MS, JB, AF, MSH), University Medical Centre Ljubljana, Ljubljana, Slovenia; Clinic for Eye Diseases (SPP), Clinical Centre of Serbia, Belgrade, Serbia; Department of Molecular Genetics (DG), Institute of Pathology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; Center for Human Genetics and Pharmacogenomics (GJ, DG), Faculty of Medicine, University of Maribor, Maribor, Slovenia; Clinical Institute of Genomic Medicine (MV, AM, BP), University Medical Centre Ljubljana, Ljubljana, Slovenia
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11
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Wongkittichote P, Duque Lasio ML, Magistrati M, Pathak S, Sample B, Carvalho DR, Ortega AB, Castro MAA, de Gusmao CM, Toler TL, Bellacchio E, Dallabona C, Shinawi M. Phenotypic, molecular, and functional characterization of COQ7-related primary CoQ 10 deficiency: Hypomorphic variants and two distinct disease entities. Mol Genet Metab 2023; 139:107630. [PMID: 37392700 PMCID: PMC10995746 DOI: 10.1016/j.ymgme.2023.107630] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 07/03/2023]
Abstract
Primary coenzyme Q10 (CoQ10) deficiency is a group of inborn errors of metabolism caused by defects in CoQ10 biosynthesis. Biallelic pathogenic variants in COQ7, encoding mitochondrial 5-demethoxyubiquinone hydroxylase, have been reported in nine patients from seven families. We identified five new patients with COQ7-related primary CoQ10 deficiency, performed clinical assessment of the patients, and studied the functional effects of current and previously reported COQ7 variants and potential treatment options. The main clinical features included a neonatal-onset presentation with severe neuromuscular, cardiorespiratory and renal involvement and a late-onset disease presenting with progressive neuropathy, lower extremity weakness, abnormal gait, and variable developmental delay. Baker's yeast orthologue of COQ7, CAT5, is required for growth on oxidative carbon sources and cat5Δ strain demonstrates oxidative growth defect. Expression of wild-type CAT5 could completely rescue the defect; however, yeast CAT5 harboring equivalent human pathogenic variants could not. Interestingly, cat5Δ yeast harboring p.Arg57Gln (equivalent to human p.Arg54Gln), p.Arg112Trp (equivalent to p.Arg107Trp), p.Ile69Asn (equivalent to p.Ile66Asn) and combination of p.Lys108Met and p.Leu116Pro (equivalent to the complex allele p.[Thr103Met;Leu111Pro]) partially rescued the growth defects, indicating these variants are hypomorphic alleles. Supplementation with 2,4 dihydroxybenzoic acid (2,4-diHB) rescued the growth defect of both the leaky and severe mutants. Overexpression of COQ8 and 2,4-diHB supplementation synergistically restored oxidative growth and respiratory defect. Overall, we define two distinct disease presentations of COQ7-related disorder with emerging genotype-phenotype correlation and validate the use of the yeast model for functional studies of COQ7 variants.
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Affiliation(s)
- Parith Wongkittichote
- Division of Genetics and Genomic Medicine, Department of Pediatrics, St. Louis Children's Hospital, Washington University School of Medicine, St. Louis, MO, USA; Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Maria Laura Duque Lasio
- Division of Genetics and Genomic Medicine, Department of Pediatrics, St. Louis Children's Hospital, Washington University School of Medicine, St. Louis, MO, USA
| | - Martina Magistrati
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Sheel Pathak
- Division of Pediatric Neurology, Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
| | | | - Daniel Rocha Carvalho
- SARAH Network Rehabilitation Hospitals, Genetic Unit, Brasilia, Federal District, Brazil
| | | | - Matheus Augusto Araújo Castro
- Mendelics Genomic Analyses, Sao Paulo, Brazil; Neurogenetics Unit, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo HCFMUSP, São Paulo, SP, Brazil
| | - Claudio M de Gusmao
- Mendelics Genomic Analyses, Sao Paulo, Brazil; Neurogenetics Unit, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo HCFMUSP, São Paulo, SP, Brazil
| | - Tomi L Toler
- Division of Genetics and Genomic Medicine, Department of Pediatrics, St. Louis Children's Hospital, Washington University School of Medicine, St. Louis, MO, USA
| | - Emanuele Bellacchio
- Molecular Genetics and Functional Genomics Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy.
| | - Marwan Shinawi
- Division of Genetics and Genomic Medicine, Department of Pediatrics, St. Louis Children's Hospital, Washington University School of Medicine, St. Louis, MO, USA.
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12
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Jacquier A, Theuriet J, Fontaine F, Mosbach V, Lacoste N, Ribault S, Risson V, Carras J, Coudert L, Simonet T, Latour P, Stojkovic T, Piard J, Cosson A, Lesca G, Bouhour F, Allouche S, Puccio H, Pegat A, Schaeffer L. Homozygous COQ7 mutation: a new cause of potentially treatable distal hereditary motor neuropathy. Brain 2023; 146:3470-3483. [PMID: 36454683 PMCID: PMC10393394 DOI: 10.1093/brain/awac453] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/30/2022] [Accepted: 11/20/2022] [Indexed: 08/03/2023] Open
Abstract
Distal hereditary motor neuropathy represents a group of motor inherited neuropathies leading to distal weakness. We report a family of two brothers and a sister affected by distal hereditary motor neuropathy in whom a homozygous variant c.3G>T (p.1Met?) was identified in the COQ7 gene. This gene encodes a protein required for coenzyme Q10 biosynthesis, a component of the respiratory chain in mitochondria. Mutations of COQ7 were previously associated with severe multi-organ disorders characterized by early childhood onset and developmental delay. Using patient blood samples and fibroblasts derived from a skin biopsy, we investigated the pathogenicity of the variant of unknown significance c.3G>T (p.1Met?) in the COQ7 gene and the effect of coenzyme Q10 supplementation in vitro. We showed that this variation leads to a severe decrease in COQ7 protein levels in the patient's fibroblasts, resulting in a decrease in coenzyme Q10 production and in the accumulation of 6-demethoxycoenzyme Q10, the COQ7 substrate. Interestingly, such accumulation was also found in the patient's plasma. Normal coenzyme Q10 and 6-demethoxycoenzyme Q10 levels were restored in vitro by using the coenzyme Q10 precursor 2,4-dihydroxybenzoic acid, thus bypassing the COQ7 requirement. Coenzyme Q10 biosynthesis deficiency is known to impair the mitochondrial respiratory chain. Seahorse experiments showed that the patient's cells mainly rely on glycolysis to maintain sufficient ATP production. Consistently, the replacement of glucose by galactose in the culture medium of these cells reduced their proliferation rate. Interestingly, normal proliferation was restored by coenzyme Q10 supplementation of the culture medium, suggesting a therapeutic avenue for these patients. Altogether, we have identified the first example of recessive distal hereditary motor neuropathy caused by a homozygous variation in the COQ7 gene, which should thus be included in the gene panels used to diagnose peripheral inherited neuropathies. Furthermore, 6-demethoxycoenzyme Q10 accumulation in the blood can be used to confirm the pathogenic nature of the mutation. Finally, supplementation with coenzyme Q10 or derivatives should be considered to prevent the progression of COQ7-related peripheral inherited neuropathy in diagnosed patients.
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Affiliation(s)
- Arnaud Jacquier
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
- Centre de Biotechnologie Cellulaire, CBC Biotec, CHU de Lyon—Hospices Civils de Lyon (HCL) groupement Est, Bron, France
| | - Julian Theuriet
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
- Hôpital Neurologique Pierre Wertheimer, Service d’électroneuromyographie et de pathologies neuromusculaires, CHU de Lyon—Hospices Civils de Lyon (HCL) groupement Est, Bron, France
| | - Fanny Fontaine
- Service de Biochimie, CHU de Caen, UMRS 1237 PhIND, Université de Caen, Caen, France
| | - Valentine Mosbach
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
| | - Nicolas Lacoste
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
| | - Shams Ribault
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
- Hôpital Henry Gabrielle, Service de Médecine Physique et de Réadaptation, CHU de Lyon—Hospices Civils de Lyon (HCL), Saint-Genis-Laval, France
| | - Valérie Risson
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
| | - Julien Carras
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
| | - Laurent Coudert
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
| | - Thomas Simonet
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
| | - Philippe Latour
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
- Unité fonctionnelle de neurogénétique moléculaire, CHU de Lyon—Hospices Civils de Lyon (HCL) groupement Est, Bron, France
| | - Tanya Stojkovic
- Institut de Myologie, Hôpital Pitié-Salpêtrière, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France
| | - Juliette Piard
- Centre de Génétique Humaine, CHU, Besançon, France
- UMR-Inserm 1231 GAD, Génétique des Anomalies du Développement, Université de Bourgogne Franche-Comté, Dijon, France
| | - Anne Cosson
- Neurologie Électrophysiologie Clinique, CHU Jean-Minjoz, Besançon, France
| | - Gaëtan Lesca
- Service de génétique, CHU de Lyon—Hospices Civils de Lyon (HCL) groupement Est, Bron, France
| | - Françoise Bouhour
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
- Hôpital Neurologique Pierre Wertheimer, Service d’électroneuromyographie et de pathologies neuromusculaires, CHU de Lyon—Hospices Civils de Lyon (HCL) groupement Est, Bron, France
| | - Stéphane Allouche
- Service de Biochimie, CHU de Caen, UMRS 1237 PhIND, Université de Caen, Caen, France
| | - Hélène Puccio
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
| | - Antoine Pegat
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
- Hôpital Neurologique Pierre Wertheimer, Service d’électroneuromyographie et de pathologies neuromusculaires, CHU de Lyon—Hospices Civils de Lyon (HCL) groupement Est, Bron, France
| | - Laurent Schaeffer
- Pathophysiology and Genetics of Neuron and Muscle, CNRS UMR 5261, INSERM U1315, Université Lyon1, Faculté de Médecine Lyon Est, Lyon, France
- Centre de Biotechnologie Cellulaire, CBC Biotec, CHU de Lyon—Hospices Civils de Lyon (HCL) groupement Est, Bron, France
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Eliyan Y, Rezania K, Gomez CM, Seibert K. Pontine stroke in a patient with Chronic Progressive External Ophthalmoplegia (CPEO): a case report. BMC Neurol 2023; 23:231. [PMID: 37316776 DOI: 10.1186/s12883-023-03249-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 05/15/2023] [Indexed: 06/16/2023] Open
Abstract
BACKGROUND Chronic progressive external ophthalmoplegia (CPEO) is a mitochondrial disease with slowly progressive bilateral ptosis and symmetric ophthalmoplegia due to a genetic mutation that results in defective oxidative phosphorylation. Common genes that are implicated in CPEO include POLG, RRM2B, ANT1 and PEO1/TWNK. Here, we report a case of a patient diagnosed with CPEO caused by a novel mutation in PEO/TWNK after suffering a right pontine stroke. CASE PRESENTATION A 70-year-old man with history of chronic progressive bilateral ptosis and ophthalmoplegia, as well as similar ocular symptoms in his father and grandfather, presented with acute onset of right hemifacial weakness and dysarthria. Brain MRI revealed an acute ischemic stroke in the right dorsal pons. The patient did not experience diplopia due to severe baseline ophthalmoplegia. Creatine kinase was elevated to 6,080 U/L upon admission and normalized over the course of one week; electromyography revealed a myopathic process. Genetic testing revealed a novel mutation c.1510G > A (p. Ala504Thr) in a pathogenic "hot spot" of the C10ORF2 gene (TWNK/PEO1), which is associated with CPEO. The mutation appears to be deleterious using several pathogenicity prediction tools. CONCLUSIONS This case report describes a patient with late-onset CPEO caused by a novel, likely pathogenic, mutation in the TWNK gene. Although the patient presented with a pontine stroke, it manifested with solely new onset facial palsy, as he had a severe underlying ophthalmoplegia secondary to his CPEO.
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Affiliation(s)
- Yazan Eliyan
- Pritzker School of Medicine, University of Chicago, Chicago, IL, USA
| | - Kourosh Rezania
- Department of Neurology, University of Chicago Medical Center, Chicago, IL, USA
| | - Christopher M Gomez
- Department of Neurology, University of Chicago Medical Center, Chicago, IL, USA
| | - Kaitlin Seibert
- Department of Neurology, University of Chicago Medical Center, Chicago, IL, USA.
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Gedikbasi A, Toksoy G, Karaca M, Gulec C, Balci MC, Gunes D, Gunes S, Aslanger AD, Unverengil G, Karaman B, Basaran S, Demirkol M, Gokcay GF, Uyguner ZO. Clinical and bi-genomic DNA findings of patients suspected to have mitochondrial diseases. Front Genet 2023; 14:1191159. [PMID: 37377599 PMCID: PMC10292751 DOI: 10.3389/fgene.2023.1191159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/02/2023] [Indexed: 06/29/2023] Open
Abstract
Background: Mitochondrial diseases are the most common group of inherited metabolic disorders, causing difficulties in definite diagnosis due to clinical and genetic heterogeneity. Clinical components are predominantly associated with pathogenic variants shown in nuclear or mitochondrial genomes that affect vital respiratory chain function. The development of high-throughput sequencing technologies has accelerated the elucidation of the genetic etiology of many genetic diseases that previously remained undiagnosed. Methods: Thirty affected patients from 24 unrelated families with clinical, radiological, biochemical, and histopathological evaluations considered for mitochondrial diseases were investigated. DNA isolated from the peripheral blood samples of probands was sequenced for nuclear exome and mitochondrial DNA (mtDNA) analyses. MtDNA sequencing was also performed from the muscle biopsy material in one patient. For segregation, Sanger sequencing is performed for pathogenic alterations in five other affected family members and healthy parents. Results: Exome sequencing revealed 14 different pathogenic variants in nine genes encoding mitochondrial function peptides (AARS2, EARS2, ECHS1, FBXL4, MICOS13, NDUFAF6, OXCT1, POLG, and TK2) in 12 patients from nine families and four variants in genes encoding important for muscle structure (CAPN3, DYSF, and TCAP) in six patients from four families. Three probands carried pathogenic mtDNA variations in two genes (MT-ATP6 and MT-TL1). Nine variants in five genes are reported for the first time with disease association: (AARS2: c.277C>T/p.(R93*), c.845C>G/p.(S282C); EARS2: c.319C>T/p.(R107C), c.1283delC/p.(P428Lfs*); ECHS1: c.161G>A/p.(R54His); c.202G>A/p.(E68Lys); NDUFAF6: c.479delA/p.(N162Ifs*27); and OXCT1: c.1370C>T/p.(T457I), c.1173-139G>T/p.(?). Conclusion: Bi-genomic DNA sequencing clarified genetic etiology in 67% (16/24) of the families. Diagnostic utility by mtDNA sequencing in 13% (3/24) and exome sequencing in 54% (13/24) of the families prioritized searching for nuclear genome pathologies for the first-tier test. Weakness and muscle wasting observed in 17% (4/24) of the families underlined that limb-girdle muscular dystrophy, similar to mitochondrial myopathy, is an essential point for differential diagnosis. The correct diagnosis is crucial for comprehensive genetic counseling of families. Also, it contributes to making treatment-helpful referrals, such as ensuring early access to medication for patients with mutations in the TK2 gene.
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Affiliation(s)
- Asuman Gedikbasi
- Department of Pediatric Basic Sciences, Institute of Child Health Istanbul University, Istanbul, Türkiye
- Division of Pediatric Nutrition and Metabolism, Department of Pediatrics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Guven Toksoy
- Department of Medical Genetics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Meryem Karaca
- Division of Pediatric Nutrition and Metabolism, Department of Pediatrics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Cagri Gulec
- Department of Medical Genetics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Mehmet Cihan Balci
- Division of Pediatric Nutrition and Metabolism, Department of Pediatrics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Dilek Gunes
- Division of Pediatric Nutrition and Metabolism, Department of Pediatrics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Seda Gunes
- Division of Pediatric Nutrition and Metabolism, Department of Pediatrics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Ayca Dilruba Aslanger
- Department of Medical Genetics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Gokcen Unverengil
- Department of Pathology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Birsen Karaman
- Department of Pediatric Basic Sciences, Institute of Child Health Istanbul University, Istanbul, Türkiye
- Department of Medical Genetics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Seher Basaran
- Department of Medical Genetics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Mubeccel Demirkol
- Division of Pediatric Nutrition and Metabolism, Department of Pediatrics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Gulden Fatma Gokcay
- Division of Pediatric Nutrition and Metabolism, Department of Pediatrics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Zehra Oya Uyguner
- Department of Medical Genetics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
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15
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Gill EL, Wang J, Viaene AN, Master SR, Ganetzky RD. Methodologies in Mitochondrial Testing: Diagnosing a Primary Mitochondrial Respiratory Chain Disorder. Clin Chem 2023:7143230. [PMID: 37099687 DOI: 10.1093/clinchem/hvad037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 03/03/2023] [Indexed: 04/28/2023]
Abstract
BACKGROUND Mitochondria are cytosolic organelles within most eukaryotic cells. Mitochondria generate the majority of cellular energy in the form of adenosine triphosphate (ATP) through oxidative phosphorylation (OxPhos). Pathogenic variants in mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) lead to defects in OxPhos and physiological malfunctions (Nat Rev Dis Primer 2016;2:16080.). Patients with primary mitochondrial disorders (PMD) experience heterogeneous symptoms, typically in multiple organ systems, depending on the tissues affected by mitochondrial dysfunction. Because of this heterogeneity, clinical diagnosis is challenging (Annu Rev Genomics Hum Genet 2017;18:257-75.). Laboratory diagnosis of mitochondrial disease depends on a multipronged analysis that can include biochemical, histopathologic, and genetic testing. Each of these modalities has complementary strengths and limitations in diagnostic utility. CONTENT The primary focus of this review is on diagnosis and testing strategies for primary mitochondrial diseases. We review tissue samples utilized for testing, metabolic signatures, histologic findings, and molecular testing approaches. We conclude with future perspectives on mitochondrial testing. SUMMARY This review offers an overview of the current biochemical, histologic, and genetic approaches available for mitochondrial testing. For each we review their diagnostic utility including complementary strengths and weaknesses. We identify gaps in current testing and possible future avenues for test development.
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Affiliation(s)
- Emily L Gill
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Jing Wang
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Angela N Viaene
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Stephen R Master
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Rebecca D Ganetzky
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
- Division of Human Genetics, Children's Hospital of Philadelphia, Mitochondrial Medicine Frontier Program, Philadelphia, PA, United States
- Department of Pediatrics, University of Pennsylvania, Philadelphia, PA, United States
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16
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Abstract
Mitochondrial diseases require customized approaches for reproductive counseling, addressing differences in recurrence risks and reproductive options. The majority of mitochondrial diseases is caused by mutations in nuclear genes and segregate in a Mendelian way. Prenatal diagnosis (PND) or preimplantation genetic testing (PGT) are available to prevent the birth of another severely affected child. In at least 15%-25% of cases, mitochondrial diseases are caused by mitochondrial DNA (mtDNA) mutations, which can occur de novo (25%) or be maternally inherited. For de novo mtDNA mutations, the recurrence risk is low and PND can be offered for reassurance. For maternally inherited, heteroplasmic mtDNA mutations, the recurrence risk is often unpredictable, due to the mitochondrial bottleneck. PND for mtDNA mutations is technically possible, but often not applicable given limitations in predicting the phenotype. Another option for preventing the transmission of mtDNA diseases is PGT. Embryos with mutant load below the expression threshold are being transferred. Oocyte donation is another safe option to prevent the transmission of mtDNA disease to a future child for couples who reject PGT. Recently, mitochondrial replacement therapy (MRT) became available for clinical application as an alternative to prevent the transmission of heteroplasmic and homoplasmic mtDNA mutations.
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17
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Schon KR, Chinnery PF. Whole-genome sequencing for mitochondrial disorders identifies unexpected mimics. Pract Neurol 2023; 23:2-3. [PMID: 36253087 DOI: 10.1136/pn-2022-003570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/18/2022] [Indexed: 02/02/2023]
Affiliation(s)
- Katherine R Schon
- Department of Clinical Neurosciences, Cambridge Biomedical Campus, Cambridge, UK
- Academic Department of Medical Genetics, Cambridge Biomedical Campus, Cambridge, UK
| | - Patrick F Chinnery
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
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18
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Smith IC, Pileggi CA, Wang Y, Kernohan K, Hartley T, McMillan HJ, Sampaio ML, Melkus G, Woulfe J, Parmar G, Bourque PR, Breiner A, Zwicker J, Pringle CE, Jarinova O, Lochmüller H, Dyment DA, Brais B, Boycott KM, Hekimi S, Harper ME, Warman-Chardon J. Novel Homozygous Variant in COQ7in Siblings With Hereditary Motor Neuropathy. Neurol Genet 2023; 9:e200048. [PMID: 37077559 PMCID: PMC10108386 DOI: 10.1212/nxg.0000000000200048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/19/2022] [Indexed: 01/26/2023]
Abstract
Background and ObjectivesCoenzyme Q10(CoQ10) is an important electron carrier and antioxidant. The COQ7 enzyme catalyzes the hydroxylation of 5-demethoxyubiquinone-10 (DMQ10), the second-to-last step in the CoQ10biosynthesis pathway. We report a consanguineous family presenting with a hereditary motor neuropathy associated with a homozygous c.1A > G p.? variant ofCOQ7with abnormal CoQ10biosynthesis.MethodsAffected family members underwent clinical assessments that included nerve conduction testing, histologic analysis, and MRI. Pathogenicity of theCOQ7variant was assessed in cultured fibroblasts and skeletal muscle using a combination of immunoblots, respirometry, and quinone analysis.ResultsThree affected siblings, ranging from 12 to 24 years of age, presented with a severe length-dependent motor neuropathy with marked symmetric distal weakness and atrophy with normal sensation. Muscle biopsy of the quadriceps revealed chronic denervation pattern. An MRI examination identified moderate to severe fat infiltration in distal muscles. Exome sequencing demonstrated the homozygousCOQ7c.1A > G p.? variant that is expected to bypass the first 38 amino acid residues at the n-terminus, initiating instead with methionine at position 39. This is predicted to cause the loss of the cleavable mitochondrial targeting sequence and 2 additional amino acids, thereby preventing the incorporation and subsequent folding of COQ7 into the inner mitochondrial membrane. Pathogenicity of theCOQ7variant was demonstrated by diminished COQ7 and CoQ10levels in muscle and fibroblast samples of affected siblings but not in the father, unaffected sibling, or unrelated controls. In addition, fibroblasts from affected siblings had substantial accumulation of DMQ10, and maximal mitochondrial respiration was impaired in both fibroblasts and muscle.DiscussionThis report describes a new neurologic phenotype ofCOQ7-related primary CoQ10deficiency. Novel aspects of the phenotype presented by this family include pure distal motor neuropathy involvement, as well as the lack of upper motor neuron features, cognitive delay, or sensory involvement in comparison with cases ofCOQ7-related CoQ10deficiency previously reported in the literature.
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Affiliation(s)
- Ian C Smith
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Chantal A Pileggi
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Ying Wang
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Kristin Kernohan
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Taila Hartley
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Hugh J McMillan
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Marcos Loreto Sampaio
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Gerd Melkus
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - John Woulfe
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Gaganvir Parmar
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Pierre R Bourque
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Ari Breiner
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Jocelyn Zwicker
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - C Elizabeth Pringle
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Olga Jarinova
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Hanns Lochmüller
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - David A Dyment
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Bernard Brais
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Kym M Boycott
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Siegfried Hekimi
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Mary-Ellen Harper
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Jodi Warman-Chardon
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
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Sanchez Marco SB, Buhl E, Firth R, Zhu B, Gainsborough M, Beleza-Meireles A, Moore S, Caswell R, Stals K, Ellard S, Kennedy C, Hodge JJL, Majumdar A. Hereditary spastic paraparesis (HSP) presenting as cerebral palsy due to ADD3 variant with mechanistic insight provided by a Drosophila γ-adducin model. Clin Genet 2022; 102:494-502. [PMID: 36046955 DOI: 10.1111/cge.14220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/25/2022] [Accepted: 08/28/2022] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Cerebral palsy (CP) causes neurological disability in early childhood. Hypoxic-ischaemic injury plays a major role in its aetiology, nevertheless, genetic and epigenetic factors may contribute to the clinical presentation. Mutations in ADD3 (encoding γ-adducin) gene have been described in a monogenic form of spastic quadriplegic cerebral palsy (OMIM 601568). METHODS We studied a sixteen-year-old male with spastic diplegia. Several investigations including neurometabolic testing, brain and spine magnetic resonance imaging (MRI) and CGH-Array were normal. Further, clinical genetics assessment and Whole Exome Sequencing (WES) gave the diagnosis. We generated an animal model using Drosophila to study the effects of γ-adducin loss and gain of function. RESULTS WES revealed a biallelic variant in the ADD3 gene, NM_016824.5(ADD3): c.1100G>A, p.(Gly367Asp). Mutations in this gene have been described as an ultra-rare autosomal recessive which is a known form of inherited cerebral palsy. Molecular modelling suggests that this mutation leads to a loss of structural integrity of γ-adducin and is therefore expected to result in a decreased level of functional protein. Pan-neuronal over-expression or knock-down of the Drosophila ortholog of ADD3 called hts caused a reduction of life span and impaired locomotion thereby phenocopying aspects of the human disease. CONCLUSION Our animal experiments present a starting point to understand the biological processes underpinning the clinical phenotype and pathogenic mechanisms, to gain insights into potential future methods for treating or preventing ADD3 related spastic quadriplegic cerebral palsy.
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Affiliation(s)
| | - Edgar Buhl
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Rosie Firth
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Bangfu Zhu
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Mary Gainsborough
- Department of Community Paediatrics, Sirona Care and Health, Bristol, UK
| | | | - Sandra Moore
- Exeter Genomics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Richard Caswell
- Exeter Genomics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Karen Stals
- Exeter Genomics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Sian Ellard
- Exeter Genomics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Cameron Kennedy
- Department of Paediatric Dermatology, Bristol Children's Hospital, Bristol, UK
| | - James J L Hodge
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Anirban Majumdar
- Department of Paediatric Neurology, Bristol Children's Hospital, Bristol, UK
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Zou TT, Sun HQ, Zhu Y, He TT, Ling WW, Zhu HM, Lin ZY, Liu YY, Liu SL, Wang H, Zhang XM. Compound heterozygous variations in IARS1 cause recurrent liver failure and growth retardation in a Chinese patient: a case report. BMC Pediatr 2022; 22:329. [PMID: 35668413 PMCID: PMC9172121 DOI: 10.1186/s12887-022-03371-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 05/18/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aminoacyl-tRNA synthetases (ARSs) are enzymes responsible for attaching amino acids to tRNA, which enables protein synthesis. Mutations in isoleucyl-tRNA synthetase (IARS1) have recently been reported to be a genetic cause for growth retardation, intellectual disability, muscular hypotonia, and infantile hepatopathy (GRIDHH). CASE PRESENTATION In this study, we reported an additional case of compound heterozygous missense variations c.701 T > C (p.L234P) and c.1555C > T (p.R519C) in IARS1, which were identified using medical exome sequencing; c.701 T > C (p.L234P) was a novel variant, and c.1555C > T (p.R519C) was found in GnomAD. Unlike other reported patients, this individual presented prominently with recurrent liver failure, which led to her death at an early age of 19 months. She also had significant growth retardation, muscular hypotonia, chubby and flabby face, recurrent loose stools, and abnormal brain computed tomography (CT), while zinc deficiency and hearing loss were not present. Studies in zebrafish embryo modeling recapitulated some of the key phenotypic traits in embryo development, neurodevelopment, liver development, and myogenesis, demonstrating that these variations caused a loss of gene function in IARS1. CONCLUSIONS We have found a novel mutation point c.701 T > C (p.L234P) in IARS1. Compound heterozygous mutations of c.701 T > C (p.L234P) and c.1555C > T (p.R519C) in IARS1 are pathogenic, which can cause GRIDHH in child.
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Affiliation(s)
- Ting-Ting Zou
- Department of Pediatric Infectious Diseases, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Hua-Qin Sun
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.,SCU-CUHK Joint Laboratory for Reproductive Medicine, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Yu Zhu
- Department of Pediatric Infectious Diseases, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Tian-Tian He
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.,Department of Medical Genetics & Prenatal Diagnosis Center, West China Second University Hospital, Sichuan University, No.20, South Section 3, Renmin Road, Chengdu, Sichuan, China
| | - Wen-Wu Ling
- Department of Ultrasound, West China University Hospital, Sichuan University, Chengdu, 610041, China
| | - Hong-Mei Zhu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.,Department of Medical Genetics & Prenatal Diagnosis Center, West China Second University Hospital, Sichuan University, No.20, South Section 3, Renmin Road, Chengdu, Sichuan, China
| | - Zi-Yuan Lin
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.,SCU-CUHK Joint Laboratory for Reproductive Medicine, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Yan-Yan Liu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.,Department of Medical Genetics & Prenatal Diagnosis Center, West China Second University Hospital, Sichuan University, No.20, South Section 3, Renmin Road, Chengdu, Sichuan, China
| | - Shan-Ling Liu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.,Department of Medical Genetics & Prenatal Diagnosis Center, West China Second University Hospital, Sichuan University, No.20, South Section 3, Renmin Road, Chengdu, Sichuan, China
| | - He Wang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.,SCU-CUHK Joint Laboratory for Reproductive Medicine, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Xue-Mei Zhang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China. .,SCU-CUHK Joint Laboratory for Reproductive Medicine, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
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Sun C, Wu S, Chen R, Liu J, Wang J, Ma Y, Yuan Z, Li Y. Whole exome sequencing is an alternative method in the diagnosis of mitochondrial DNA diseases. Mol Genet Genomic Med 2022; 10:e1943. [PMID: 35388601 PMCID: PMC9184660 DOI: 10.1002/mgg3.1943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 02/11/2022] [Accepted: 03/25/2022] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Mitochondrial disease (MD) is genetically a heterogeneous group of disorders with impairment in respiratory chain complexes or pathways associated with the mitochondrial function. Nowadays, it is still a challenge for the genetic screening of MD due to heteroplasmy of mitochondrial genome and the complex model of inheritance. This study was designed to investigate the feasibility of whole exome sequencing (WES)-based testing as an alternative option for the diagnosis of MD. METHODS A Chinese Han cohort of 48 patients with suspect MD features was tested using nanoWES, which was a self-designed WES technique that covered the complete mtDNA genome and 21,019 nuclear genes. Fourteen patients were identified with a single genetic variant and three with single deletion in mtDNA. RESULTS The heteroplasmy levels of variants in mitochondrial genome range from 11% to 100%. NanoWES failed to identify multiple deletions in mtDNA compared with long range PCR and massively parallel sequencing (LR-PCR/MPS). However, our testing showed obvious advantages in identifying variations in nuclear DNA. Based on nanoWES, we identified two patients with nuclear DNA variation. One of them showed Xp22.33-q28 duplication, which indicated a possibility of Klinefelter syndrome. CONCLUSION NanoWES yielded a diagnostic rate of 35.4% for MD. With the rapid advances of next generation sequencing technique and decrease in cost, we recommend the usage of nanoWES as a first-line method in clinical diagnosis.
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Affiliation(s)
- Chong Sun
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | | | | | - Junwu Liu
- Berry Genomics Co., Ltd, Beijing, China
| | | | - Yanyun Ma
- Berry Genomics Co., Ltd, Beijing, China
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22
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Wang Y, Gumus E, Hekimi S. A novel COQ7 mutation causing primarily neuromuscular pathology and its treatment options. Mol Genet Metab Rep 2022; 31:100877. [PMID: 35782625 PMCID: PMC9248208 DOI: 10.1016/j.ymgmr.2022.100877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 04/27/2022] [Indexed: 11/21/2022] Open
Abstract
Coenzyme Q10 (CoQ10) is necessary as electron transporter in mitochondrial respiration and other cellular functions. CoQ10 is synthesized by all cells and defects in the synthesis pathway result in primary CoQ10 deficiency that frequently leads to severe mitochondrial disease syndrome. CoQ10 is exceedingly hydrophobic, insoluble, and poorly bioavailable, with the result that dietary CoQ10 supplementation produces no or only minimal relief for patients. We studied a patient from Turkey and identified and characterized a new mutation in the CoQ10 biosynthetic gene COQ7 (c.161G > A; p.Arg54Gln). We find that unexpected neuromuscular pathology can accompany CoQ10 deficiency caused by a COQ7 mutation. We also show that by-passing the need for COQ7 by providing the unnatural precursor 2,4-dihydroxybenzoic acid, as has been proposed, is unlikely to be an effective and safe therapeutic option. In contrast, we show for the first time in human patient cells that the respiratory defect resulting from CoQ10 deficiency is rescued by providing CoQ10 formulated with caspofungin (CF/CoQ). Caspofungin is a clinically approved intravenous fungicide whose surfactant properties lead to CoQ10 micellization, complete water solubilization, and efficient uptake by cells and organs in animal studies. These findings reinforce the possibility of using CF/CoQ in the clinical treatment of CoQ10-deficient patients.
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23
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Lopriore P, Ricciarini V, Siciliano G, Mancuso M, Montano V. Mitochondrial Ataxias: Molecular Classification and Clinical Heterogeneity. Neurol Int 2022; 14:337-356. [PMID: 35466209 PMCID: PMC9036286 DOI: 10.3390/neurolint14020028] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/26/2022] [Accepted: 03/28/2022] [Indexed: 01/25/2023] Open
Abstract
Ataxia is increasingly being recognized as a cardinal manifestation in primary mitochondrial diseases (PMDs) in both paediatric and adult patients. It can be caused by disruption of cerebellar nuclei or fibres, its connection with the brainstem, or spinal and peripheral lesions leading to proprioceptive loss. Despite mitochondrial ataxias having no specific defining features, they should be included in hereditary ataxias differential diagnosis, given the high prevalence of PMDs. This review focuses on the clinical and neuropathological features and genetic background of PMDs in which ataxia is a prominent manifestation.
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24
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Mahmud S, Biswas S, Afrose S, Mita MA, Hasan MR, Shimu MSS, Paul GK, Chung S, Saleh MA, Alshehri S, Ghoneim MM, Alruwaily M, Kim B. Use of Next-Generation Sequencing for Identifying Mitochondrial Disorders. Curr Issues Mol Biol 2022; 44:1127-48. [PMID: 35723297 PMCID: PMC8947152 DOI: 10.3390/cimb44030074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/18/2022] [Accepted: 02/24/2022] [Indexed: 12/06/2022] Open
Abstract
Mitochondria are major contributors to ATP synthesis, generating more than 90% of the total cellular energy production through oxidative phosphorylation (OXPHOS): metabolite oxidation, such as the β-oxidation of fatty acids, and the Krebs’s cycle. OXPHOS inadequacy due to large genetic lesions in mitochondrial as well as nuclear genes and homo- or heteroplasmic point mutations in mitochondrially encoded genes is a characteristic of heterogeneous, maternally inherited genetic disorders known as mitochondrial disorders that affect multisystemic tissues and organs with high energy requirements, resulting in various signs and symptoms. Several traditional diagnostic approaches, including magnetic resonance imaging of the brain, cardiac testing, biochemical screening, variable heteroplasmy genetic testing, identifying clinical features, and skeletal muscle biopsies, are associated with increased risks, high costs, a high degree of false-positive or false-negative results, or a lack of precision, which limits their diagnostic abilities for mitochondrial disorders. Variable heteroplasmy levels, mtDNA depletion, and the identification of pathogenic variants can be detected through genetic sequencing, including the gold standard Sanger sequencing. However, sequencing can be time consuming, and Sanger sequencing can result in the missed recognition of larger structural variations such as CNVs or copy-number variations. Although each sequencing method has its own limitations, genetic sequencing can be an alternative to traditional diagnostic methods. The ever-growing roster of possible mutations has led to the development of next-generation sequencing (NGS). The enhancement of NGS methods can offer a precise diagnosis of the mitochondrial disorder within a short period at a reasonable expense for both research and clinical applications.
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25
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Legro NR, Kumar A, Aliu E. Case report of atypical Leigh syndrome in an adolescent male with novel biallelic variants in NDUFAF5 and review of the natural history of NDUFAF5-related disorders. Am J Med Genet A 2021; 188:896-899. [PMID: 34797029 DOI: 10.1002/ajmg.a.62568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/15/2021] [Accepted: 11/02/2021] [Indexed: 11/09/2022]
Abstract
NDUFAF5 encodes a Complex I assembly factor which is critical to the modification of a core subunit, NDUFS7, in early Complex I factor assembly. Mutations in NDUFAF5 have been previously shown to cause Complex I deficiency leading to mitochondrial respiratory chain impairment. More than 15 individuals affected by variants in NDUFAF5 have been described; however, there is phenotypic heterogeneity within this cohort. Some individuals display features of classical Leigh syndrome with early onset neurodegeneration whereas others live into early adulthood with progressive neurological deficits. Here, we present a clinical report of a 17-year-old African American individual with compound heterozygous mutations in NDUFAF5. The individual presented with childhood onset bilateral optic atrophy and developed progressive neuromuscular decline with relatively preserved cognition over time.
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Affiliation(s)
- Nicole R Legro
- Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA.,Penn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
| | - Ashutosh Kumar
- Penn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA.,Division of Neurology, Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Ermal Aliu
- Penn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA.,Division of Medical Genetics, Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
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26
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Schon KR, Horvath R, Wei W, Calabrese C, Tucci A, Ibañez K, Ratnaike T, Pitceathly RDS, Bugiardini E, Quinlivan R, Hanna MG, Clement E, Ashton E, Sayer JA, Brennan P, Josifova D, Izatt L, Fratter C, Nesbitt V, Barrett T, McMullen DJ, Smith A, Deshpande C, Smithson SF, Festenstein R, Canham N, Caulfield M, Houlden H, Rahman S, Chinnery PF. Use of whole genome sequencing to determine genetic basis of suspected mitochondrial disorders: cohort study. BMJ 2021; 375:e066288. [PMID: 34732400 PMCID: PMC8565085 DOI: 10.1136/bmj-2021-066288] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/11/2021] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine whether whole genome sequencing can be used to define the molecular basis of suspected mitochondrial disease. DESIGN Cohort study. SETTING National Health Service, England, including secondary and tertiary care. PARTICIPANTS 345 patients with suspected mitochondrial disorders recruited to the 100 000 Genomes Project in England between 2015 and 2018. INTERVENTION Short read whole genome sequencing was performed. Nuclear variants were prioritised on the basis of gene panels chosen according to phenotypes, ClinVar pathogenic/likely pathogenic variants, and the top 10 prioritised variants from Exomiser. Mitochondrial DNA variants were called using an in-house pipeline and compared with a list of pathogenic variants. Copy number variants and short tandem repeats for 13 neurological disorders were also analysed. American College of Medical Genetics guidelines were followed for classification of variants. MAIN OUTCOME MEASURE Definite or probable genetic diagnosis. RESULTS A definite or probable genetic diagnosis was identified in 98/319 (31%) families, with an additional 6 (2%) possible diagnoses. Fourteen of the diagnoses (4% of the 319 families) explained only part of the clinical features. A total of 95 different genes were implicated. Of 104 families given a diagnosis, 39 (38%) had a mitochondrial diagnosis and 65 (63%) had a non-mitochondrial diagnosis. CONCLUSION Whole genome sequencing is a useful diagnostic test in patients with suspected mitochondrial disorders, yielding a diagnosis in a further 31% after exclusion of common causes. Most diagnoses were non-mitochondrial disorders and included developmental disorders with intellectual disability, epileptic encephalopathies, other metabolic disorders, cardiomyopathies, and leukodystrophies. These would have been missed if a targeted approach was taken, and some have specific treatments.
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Affiliation(s)
- Katherine R Schon
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
- East Anglian Medical Genetics Service, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Rita Horvath
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Wei Wei
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Claudia Calabrese
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Arianna Tucci
- William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Kristina Ibañez
- William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Thiloka Ratnaike
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
- Department of Paediatrics, University of Cambridge, Cambridge, UK
| | - Robert D S Pitceathly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Enrico Bugiardini
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Rosaline Quinlivan
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Michael G Hanna
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Emma Clement
- Department of Clinical Genetics and Genomic Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Emma Ashton
- NHS North Thames Genomic Laboratory Hub, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - John A Sayer
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Paul Brennan
- Northern Genetics Service, Newcastle Hospitals NHS Foundation Trust, International Centre for Life, Newcastle upon Tyne, UK
| | - Dragana Josifova
- Department of Clinical Genetics, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Louise Izatt
- Department of Clinical Genetics, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Carl Fratter
- NHS Highly Specialised Services for Rare Mitochondrial Disorders - Oxford Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Victoria Nesbitt
- NHS Highly Specialised Services for Rare Mitochondrial Disorders - Oxford Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Timothy Barrett
- Central and South Genome Medicine Service Alliance and Genomics Laboratory Hub, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Dominic J McMullen
- Central and South Genome Medicine Service Alliance and Genomics Laboratory Hub, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
| | - Audrey Smith
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester, UK
| | - Charulata Deshpande
- Department of Clinical Genetics, Guy's and St Thomas' NHS Foundation Trust, London, UK
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester, UK
| | - Sarah F Smithson
- Department of Brain Sciences, London Institute of Medical Sciences, Mansfield Centre for Inovation, Imperial College, Hammersmith Hospital, London, UK
| | | | - Natalie Canham
- Liverpool Centre for Genomic Medicine, Liverpool Women's Hospital, Liverpool, UK
| | - Mark Caulfield
- Genomics England, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
- Neurology and Mitochondrial Disorders Genomics Clinical Interpretation Partnership, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Shamima Rahman
- Neurology and Mitochondrial Disorders Genomics Clinical Interpretation Partnership, William Harvey Research Institute, Queen Mary University of London, London, UK
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
- Mitochondrial Research Group, Department of Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Patrick F Chinnery
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
- Neurology and Mitochondrial Disorders Genomics Clinical Interpretation Partnership, William Harvey Research Institute, Queen Mary University of London, London, UK
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27
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Abstract
Neurological diseases affect 3-5% of children and, apart from cardiovascular diseases and cancer, represent the most prominent cause of morbidity and mortality in adults and particularly in the aged population of western Europe. Neuromuscular disorders are a subgroup of neurological diseases and often have a genetic origin, which leads to familial clustering. Despite the enormous progress in the analysis of the genome, such as by sequence analysis of coding regions of deoxyribonucleic acid or even the entire deoxyribonucleic acid sequence, in approximately 50% of the patients suffering from rare forms of neurological diseases the genetic cause remains unsolved. The reasons for this limited detection rate are presented in this article. If a treatment concept is available, under certain conditions this can have an impact on the adequate and early treatment of these patients. Considering neuromuscular disorders as a paradigm, this article reports on the advantages of the inclusion of next generation sequencing analysis-based DNA investigations as an omics technology (genomics) and the advantage of the integration with protein analyses (proteomics). A special focus is on the combination of genomics and proteomics in the sense of a proteogenomic approach in the diagnostics and research of these diseases. Along this line, this article presents a proteogenomic approach in the context of a multidisciplinary project aiming towards improved diagnostic work-up and future treatment of patients with neuromuscular diseases; "NMD-GPS: gene and protein signatures as a global positioning system in patients suffering from neuromuscular diseases".
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Affiliation(s)
- Andrea Gangfuß
- Abteilung für Neuropädiatrie, Universitätsmedizin Essen, Hufelandstrasse 55, 45147, Essen, Deutschland
| | - Ulrike Schara-Schmidt
- Abteilung für Neuropädiatrie, Universitätsmedizin Essen, Hufelandstrasse 55, 45147, Essen, Deutschland
| | - Andreas Roos
- Abteilung für Neuropädiatrie, Universitätsmedizin Essen, Hufelandstrasse 55, 45147, Essen, Deutschland. .,Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Kanada.
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28
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Guo L, Engelen BPH, Hemel IMGM, de Coo IFM, Vreeburg M, Sallevelt SCEH, Hellebrekers DMEI, Jacobs EH, Sadeghi-Niaraki F, van Tienen FHJ, Smeets HJM, Gerards M. Pathogenic SLIRP variants as a novel cause of autosomal recessive mitochondrial encephalomyopathy with complex I and IV deficiency. Eur J Hum Genet 2021; 29:1789-1795. [PMID: 34426662 DOI: 10.1038/s41431-021-00947-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 06/09/2021] [Accepted: 08/10/2021] [Indexed: 12/26/2022] Open
Abstract
In a Dutch non-consanguineous patient having mitochondrial encephalomyopathy with complex I and complex IV deficiency, whole exome sequencing revealed two compound heterozygous variants in SLIRP. SLIRP gene encodes a stem-loop RNA-binding protein that regulates mitochondrial RNA expression and oxidative phosphorylation (OXPHOS). A frameshift and a deep-intronic splicing variant reduced the amount of functional wild-type SLIRP RNA to 5%. Consequently, in patient fibroblasts, MT-ND1, MT-ND6, and MT-CO1 expression was reduced. Lentiviral transduction of wild-type SLIRP cDNA in patient fibroblasts increased MT-ND1, MT-ND6, and MT-CO1 expression (2.5-7.2-fold), whereas mutant cDNAs did not. A fourfold decrease of citrate synthase versus total protein ratio in patient fibroblasts indicated that the resulting reduced mitochondrial mass caused the OXPHOS deficiency. Transduction with wild-type SLIRP cDNA led to a 2.4-fold increase of this ratio and partly restored OXPHOS activity. This confirmed causality of the SLIRP variants. In conclusion, we report SLIRP variants as a novel cause of mitochondrial encephalomyopathy with OXPHOS deficiency.
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Affiliation(s)
- Le Guo
- School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, the Netherlands.,Department of Toxicogenomics, Clinical Genomics Unit, Maastricht University, Maastricht, the Netherlands
| | - Bob P H Engelen
- Maastricht Center for Systems Biology (MacsBio), Maastricht University, Maastricht, the Netherlands
| | - Irene M G M Hemel
- Maastricht Center for Systems Biology (MacsBio), Maastricht University, Maastricht, the Netherlands
| | - Irenaeus F M de Coo
- School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, the Netherlands.,Department of Toxicogenomics, Clinical Genomics Unit, Maastricht University, Maastricht, the Netherlands
| | - Maaike Vreeburg
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Suzanne C E H Sallevelt
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Debby M E I Hellebrekers
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Ed H Jacobs
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Farah Sadeghi-Niaraki
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Florence H J van Tienen
- School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, the Netherlands.,Department of Toxicogenomics, Clinical Genomics Unit, Maastricht University, Maastricht, the Netherlands
| | - Hubert J M Smeets
- School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, the Netherlands. .,Department of Toxicogenomics, Clinical Genomics Unit, Maastricht University, Maastricht, the Netherlands. .,School for Oncology and Developmental Biology (GROW), Maastricht University, Maastricht, the Netherlands.
| | - Mike Gerards
- Maastricht Center for Systems Biology (MacsBio), Maastricht University, Maastricht, the Netherlands
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29
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Gburek-Augustat J, Schoene-Bake JC, Bültmann E, Haack T, Buchert R, Synofzik M, Biskup S, Feuerhake F, Sorge I, Hartmann H. Pitfalls in Genetic Diagnostics: Why Phenotyping is Essential. Neuropediatrics 2021; 52:274-283. [PMID: 33791999 DOI: 10.1055/s-0041-1726306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
New genetic testing technologies have revolutionized medicine within the past years. It is foreseeable that the development will continue with the introduction of new techniques. Nevertheless, despite improved technology, an exact clinical description of the phenotype is still necessary and it is important to critically question findings, both before initiating genetic testing and when interpreting the results. We present four brief case vignettes to point out difficulties associated with correctly interpreting genetic findings.
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Affiliation(s)
- Janina Gburek-Augustat
- Division of Neuropediatrics, University Hospital, Hospital for Children and Adolescents, Leipzig, Germany.,Clinic for Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany.,Department of Neuropediatrics, Developmental Neurology, Social Paediatrics, University Children's Hospital Tuebingen, Tuebingen, Germany
| | - Jan-Christoph Schoene-Bake
- Clinic for Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany.,Gemeinschaftspraxis fuer Humangenetik, Hamburg, Germany
| | - Eva Bültmann
- Institute of Diagnostic and Interventional Neuroradiology, Hannover Medical School, Hannover, Germany
| | - Tobias Haack
- Department of Medical Genetics and Applied Genomics, Rare Disease Center Tübingen, University of Tübingen, Tübingen, Germany
| | - Rebecca Buchert
- Department of Medical Genetics and Applied Genomics, Rare Disease Center Tübingen, University of Tübingen, Tübingen, Germany
| | - Matthis Synofzik
- Department for Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Saskia Biskup
- CeGaT GmbH, Center for Genomics and Transcriptomics, Tübingen, Germany
| | | | - Ina Sorge
- Department of Pediatric Radiology, University Hospital Leipzig, Leipzig, Germany
| | - Hans Hartmann
- Clinic for Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
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30
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Manaspon C, Boonsimma P, Phokaew C, Theerapanon T, Sriwattanapong K, Porntaveetus T, Shotelersuk V. Expanding the genotypic spectrum of PYCR2 and a common ancestry in Thai patients with hypomyelinating leukodystrophy 10. Am J Med Genet A 2021; 185:3068-3073. [PMID: 34037307 DOI: 10.1002/ajmg.a.62365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/27/2021] [Accepted: 05/08/2021] [Indexed: 11/10/2022]
Abstract
PYCR2 pathogenic variants lead to an autosomal recessive hypomyelinating leukodystrophy 10 (HLD10), characterized by global developmental delay, microcephaly, facial dysmorphism, movement disorder, and hypomyelination. This study identified the first two unrelated Thai patients with HLD10. Patient 1 harbored the novel compound heterozygous variants, c.257T>G (p.Val86Gly) and c.400G>A (p.Val134Met), whereas patient 2 possessed the homozygous variant, c.400G>A (p.Val134Met), in PYCR2. Haplotype analysis revealed that the two families' members shared a 2.3 Mb region covering the c.400G>A variant, indicating a common ancestry. The variant was estimated to age 1450 years ago. Since the c.400G>A was detected in three out of four mutant alleles and with a common ancestry, this variant might be common in Thai patients. We also reviewed the phenotype and genotype of all 35 previously reported PYCR2 patients and found that majorities of cases were homozygous with a consanguineous family history, except patient 1 and another reported case who were compound heterozygous. All patients had microcephaly and developmental delay. Hypotonia and peripheral spasticity were common. Hypomyelination or delayed myelination was a typical radiographic feature. Here, we report the first two Thai patients with HLD10 with the novel PYCR2 variants expanding the genotypic spectrum and suggest that the c.400G>A might be a common mutation in Thai patients.
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Affiliation(s)
- Chawan Manaspon
- Biomedical Engineering Institute, Chiang Mai University, Chiang Mai, Thailand.,Genomics and Precision Dentistry Research Unit, Department of Physiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Ponghatai Boonsimma
- Division of Medical Genetics and Metabolism, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Chureerat Phokaew
- Center of Excellence for Medical Genomics, Medical Genomics Cluster, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, The Thai Red Cross Society, Bangkok, Thailand
| | - Thanakorn Theerapanon
- Genomics and Precision Dentistry Research Unit, Department of Physiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Kanokwan Sriwattanapong
- Genomics and Precision Dentistry Research Unit, Department of Physiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Thantrira Porntaveetus
- Genomics and Precision Dentistry Research Unit, Department of Physiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Vorasuk Shotelersuk
- Center of Excellence for Medical Genomics, Medical Genomics Cluster, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, The Thai Red Cross Society, Bangkok, Thailand
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31
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Forny P, Footitt E, Davison JE, Lam A, Woodward CE, Batzios S, Bhate S, Chakrapani A, Cleary M, Gissen P, Grunewald S, Hurst JA, Scott R, Heales S, Jacques TS, Cullup T, Rahman S. Diagnosing Mitochondrial Disorders Remains Challenging in the Omics Era. Neurol Genet 2021; 7:e597. [PMID: 34056100 PMCID: PMC8161540 DOI: 10.1212/nxg.0000000000000597] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/06/2021] [Indexed: 02/06/2023]
Abstract
Objective We hypothesized that novel investigative pathways are needed to decrease diagnostic odysseys in pediatric mitochondrial disease and sought to determine the utility of clinical exome sequencing in a large cohort with suspected mitochondrial disease and to explore whether any of the traditional indicators of mitochondrial disease predict a confirmed genetic diagnosis. Methods We investigated a cohort of 85 pediatric patients using clinical exome sequencing and compared the results with the outcome of traditional diagnostic tests, including biochemical testing of routine parameters (lactate, alanine, and proline), neuroimaging, and muscle biopsy with histology and respiratory chain enzyme activity studies. Results We established a genetic diagnosis in 36.5% of the cohort and report 20 novel disease-causing variants (1 mitochondrial DNA). Counterintuitively, routine biochemical markers were more predictive of mitochondrial disease than more invasive and elaborate muscle studies. Conclusions We propose using biochemical markers to support the clinical suspicion of mitochondrial disease and then apply first-line clinical exome sequencing to identify a definite diagnosis. Muscle biopsy studies should only be used in clinically urgent situations or to confirm an inconclusive genetic result. Classification of Evidence This is a Class II diagnostic accuracy study showing that the combination of CSF and plasma biochemical tests plus neuroimaging could predict the presence or absence of exome sequencing confirmed mitochondrial disorders.
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Affiliation(s)
- Patrick Forny
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Emma Footitt
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - James E Davison
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Amanda Lam
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Cathy E Woodward
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Spyros Batzios
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Sanjay Bhate
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Anupam Chakrapani
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Maureen Cleary
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Paul Gissen
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Stephanie Grunewald
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Jane A Hurst
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Richard Scott
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Simon Heales
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Thomas S Jacques
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Thomas Cullup
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
| | - Shamima Rahman
- Mitochondrial Research Group (P.F., S.R.), UCL Great Ormond Street Institute of Child Health; Metabolic Medicine Department (P.F., E.F., J.E.D., S. Batzios, A.C., M.C., P.G., S.G., S.R.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurometabolic Unit (A.L., S.H.), National Hospital for Neurology and Neurosurgery; Department of Chemical Pathology (A.L., S.H.), Great Ormond Street Hospital for Children NHS Foundation Trust; Neurogenetics Unit (C.E.W.), National Hospital for Neurology and Neurosurgery; Department of Neurology (S. Bhate), Department of Clinical Genetics (J.A.H., R.S.), North East Thames Regional Genetics Service, DBC Programme (T.S.J.), UCL Great Ormond Street Institute of Child Health and Department of Histopathology, and London North Genomic Laboratory Hub (T.C.), Great Ormond Street Hospital for Children NHS Foundation Trust, United Kingdom
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Abstract
Our understanding of genetic disease(s) has increased exponentially since the completion of human genome sequencing and the development of numerous techniques to detect genetic variants. These techniques have not only allowed us to diagnose genetic disease, but in so doing, also provide increased understanding of the pathogenesis of these diseases to aid in developing appropriate therapeutic options. Additionally, the advent of next-generation or massively parallel sequencing (NGS/MPS) is increasingly being used in the clinical setting, as it can detect a number of abnormalities from point mutations to chromosomal rearrangements as well as aberrations within the transcriptome. In this article, we will discuss the use of multiple techniques that are used in genetic diagnosis. © 2020 by John Wiley & Sons, Inc.
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Affiliation(s)
- Rashmi S Goswami
- Department of Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Sunnybrook Research Institute, Biological Sciences, Odette Cancer Research Program, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Shuko Harada
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama
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33
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Kose M, Isik E, Aykut A, Durmaz A, Kose E, Ersoy M, Diniz G, Adebali O, Ünalp A, Yilmaz Ü, Karaoğlu P, Edizer S, Tekin HG, Özdemir TR, Atik T, Onay H, Özkınay F. The utility of next-generation sequencing technologies in diagnosis of Mendelian mitochondrial diseases and reflections on clinical spectrum. J Pediatr Endocrinol Metab 2021; 34:417-430. [PMID: 33629572 DOI: 10.1515/jpem-2020-0410] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 12/10/2020] [Indexed: 02/03/2023]
Abstract
OBJECTIVES Diagnostic process of mitochondrial disorders (MD) is challenging because of the clinical variability and genetic heterogeneity of these conditions. Next-Generation Sequencing (NGS) technology offers a high-throughput platform for nuclear MD. METHODS We included 59 of 72 patients that undergone WES and targeted exome sequencing panel suspected to have potential PMDs. Patients who were included in the analysis considering the possible PMD were reviewed retrospectively and scored according to the Mitochondrial Disease Criteria Scale. RESULTS Sixty-one percent of the patients were diagnosed with whole-exome sequencing (WES) (36/59) and 15% with targeted exome sequencing (TES) (9/59). Patients with MD-related gene defects were included in the mito group, patients without MD-related gene defects were included in the nonmito group, and patients in whom no etiological cause could be identified were included in the unknown etiology group. In 11 out of 36 patients diagnosed with WES, a TES panel was applied prior to WES. In 47 probands in 39 genes (SURF1, SDHAF1, MTO1, FBXL4, SLC25A12, GLRX5, C19oRF12, NDUFAF6, DARS2, BOLA3, SLC19A3, SCO1, HIBCH, PDHA1, PDHAX, PC, ETFA, TRMU, TUFM, NDUFS6, WWOX, UBCD TREX1, ATL1, VAC14, GFAP, PLA2G6, TPRKB, ATP8A2, PEX13, IGHMBP2, LAMB2, LPIN1, GFPT1, CLN5, DOLK) (20 mito group, 19 nonmito group) 59 variants (31 mito group, 18 nonmito group) were detected. Seven novel variants in the mito group (SLC25A12, GLRX5, DARS2, SCO1, PC, ETFA, NDUFS6), nine novel variants in the nonmito group (IVD, GCDH, COG4, VAC14, GFAP, PLA2G6, ATP8A2, PEX13, LPIN1) were detected. CONCLUSIONS We explored the feasibility of identifying pathogenic alleles using WES and TES in MD. Our results show that WES is the primary method of choice in the diagnosis of MD until at least all genes responsible for PMD are found and are highly effective in facilitating the diagnosis process.
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Affiliation(s)
- Melis Kose
- Department of Pediatrics, Division of Inborn Errors of Metabolism, İzmir Katip Çelebi University, Izmir, Turkey.,Department of Pediatrics, Division of Genetics, Ege University, Izmir, Turkey
| | - Esra Isik
- Department of Pediatrics, Division of Genetics, Ege University, Izmir, Turkey
| | - Ayça Aykut
- Department of Medical Genetics, Ege University, Izmir, Turkey
| | - Asude Durmaz
- Department of Medical Genetics, Ege University, Izmir, Turkey
| | - Engin Kose
- Department of Pediatrics, Division of Inborn Errors of Metabolism, Ankara University, Ankara, Turkey
| | - Melike Ersoy
- Department of Pediatrics, Division of Inborn Errors of Metabolism, Health Sciences University, Bakırkoy Sadi Konuk Research and Training Hospital, Istanbul, Turkey
| | - Gulden Diniz
- Department of Pathology, İzmir Democrasy University, Izmir, Turkey
| | - Ogun Adebali
- Adebali Lab, Molecular Biology, Genetics and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
| | - Aycan Ünalp
- Department of Pediatric Neurology, Health Sciences University Dr. Behçet Uz Children Research and Training Hospital, Izmir, Turkey
| | - Ünsal Yilmaz
- Department of Pediatric Neurology, Health Sciences University Dr. Behçet Uz Children Research and Training Hospital, Izmir, Turkey
| | - Pakize Karaoğlu
- Department of Pediatric Neurology, Health Sciences University Dr. Behçet Uz Children Research and Training Hospital, Izmir, Turkey
| | - Selvinaz Edizer
- Department of Pediatrics, Division of Pediatric Neurology, Kanuni Sultan Suleyman University, Istanbul, Turkey
| | - Hande Gazeteci Tekin
- Department of Pediatrics, Division of Pediatric Neurology, Çiğli Training and Research Hospital, Izmir, Turkey
| | - Taha Reşid Özdemir
- Department of Medical Genetics, Health Sciences University Tepecik Training and Research Hospital, Izmir, Turkey
| | - Tahir Atik
- Department of Pediatrics, Division of Genetics, Ege University, Izmir, Turkey
| | - Hüseyin Onay
- Department of Medical Genetics, Ege University, Izmir, Turkey
| | - Ferda Özkınay
- Department of Pediatrics, Division of Genetics, Ege University, Izmir, Turkey
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34
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Rius R, Compton AG, Baker NL, Welch AE, Coman D, Kava MP, Minoche AE, Cowley MJ, Thorburn DR, Christodoulou J. Application of Genome Sequencing from Blood to Diagnose Mitochondrial Diseases. Genes (Basel) 2021; 12:genes12040607. [PMID: 33924034 PMCID: PMC8072654 DOI: 10.3390/genes12040607] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 12/23/2022] Open
Abstract
Mitochondrial diseases can be caused by pathogenic variants in nuclear or mitochondrial DNA-encoded genes that often lead to multisystemic symptoms and can have any mode of inheritance. Using a single test, Genome Sequencing (GS) can effectively identify variants in both genomes, but it has not yet been universally used as a first-line approach to diagnosing mitochondrial diseases due to related costs and challenges in data analysis. In this article, we report three patients with mitochondrial disease molecularly diagnosed through GS performed on DNA extracted from blood to demonstrate different diagnostic advantages of this technology, including the detection of a low-level heteroplasmic pathogenic variant, an intragenic nuclear DNA deletion, and a large mtDNA deletion. Current technical improvements and cost reductions are likely to lead to an expanded routine diagnostic usage of GS and of the complementary “Omic” technologies in mitochondrial diseases.
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Affiliation(s)
- Rocio Rius
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia; (R.R.); (A.G.C.); (N.L.B.) (A.E.W.); (D.R.T.)
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Alison G. Compton
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia; (R.R.); (A.G.C.); (N.L.B.) (A.E.W.); (D.R.T.)
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Naomi L. Baker
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia; (R.R.); (A.G.C.); (N.L.B.) (A.E.W.); (D.R.T.)
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
- Victorian Clinical Genetic Services, Melbourne, VIC 3052, Australia
| | - AnneMarie E. Welch
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia; (R.R.); (A.G.C.); (N.L.B.) (A.E.W.); (D.R.T.)
| | - David Coman
- Department of Metabolic Medicine, Queensland Children’s Hospital, Brisbane, QLD 4101, Australia;
- School of Clinical Medicine, University of Queensland, Brisbane, QLD 4072, Australia
- School of Medicine, Griffith University, Gold Coast, QLD 4222, Australia
| | - Maina P. Kava
- Department of Neurology, Perth Children’s Hospital, Perth, WA 6009, Australia;
- Department of Metabolic Medicine and Rheumatology, Perth Children’s Hospital, Perth, WA 6009, Australia
| | - Andre E. Minoche
- Kinghorn Centre for Clinical Genomics, Garvan Institute, University of New South Wales, Randwick, NSW 2010, Australia;
| | - Mark J. Cowley
- Precision Medicine Theme, Children’s Cancer Institute, Kensington, NSW 2750, Australia;
- School of Women’s and Children’s Health, University of New South Wales, Randwick, NSW 2031, Australia
| | - David R. Thorburn
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia; (R.R.); (A.G.C.); (N.L.B.) (A.E.W.); (D.R.T.)
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
- Victorian Clinical Genetic Services, Melbourne, VIC 3052, Australia
| | - John Christodoulou
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia; (R.R.); (A.G.C.); (N.L.B.) (A.E.W.); (D.R.T.)
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
- Victorian Clinical Genetic Services, Melbourne, VIC 3052, Australia
- Correspondence: ; Tel.: +61-39936-6353
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35
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Barp A, Mosca L, Sansone VA. Facilitations and Hurdles of Genetic Testing in Neuromuscular Disorders. Diagnostics (Basel) 2021; 11:diagnostics11040701. [PMID: 33919863 PMCID: PMC8070835 DOI: 10.3390/diagnostics11040701] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/11/2021] [Accepted: 04/12/2021] [Indexed: 12/11/2022] Open
Abstract
Neuromuscular disorders (NMDs) comprise a heterogeneous group of disorders that affect about one in every thousand individuals worldwide. The vast majority of NMDs has a genetic cause, with about 600 genes already identified. Application of genetic testing in NMDs can be useful for several reasons: correct diagnostic definition of a proband, extensive familial counselling to identify subjects at risk, and prenatal diagnosis to prevent the recurrence of the disease; furthermore, identification of specific genetic mutations still remains mandatory in some cases for clinical trial enrollment where new gene therapies are now approaching. Even though genetic analysis is catching on in the neuromuscular field, pitfalls and hurdles still remain and they should be taken into account by clinicians, as for example the use of next generation sequencing (NGS) where many single nucleotide variants of “unknown significance” can emerge, complicating the correct interpretation of genotype-phenotype relationship. Finally, when all efforts in terms of molecular analysis have been carried on, a portion of patients affected by NMDs still remain “not genetically defined”. In the present review we analyze the evolution of genetic techniques, from Sanger sequencing to NGS, and we discuss “facilitations and hurdles” of genetic testing which must always be balanced by clinicians, in order to ensure a correct diagnostic definition, but taking always into account the benefit that the patient could obtain especially in terms of “therapeutic offer”.
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Affiliation(s)
- Andrea Barp
- The NEMO Clinical Center in Milan, Neurorehabilitation Unit, University of Milan, Piazza Ospedale Maggiore 3, 20162 Milano, Italy;
- Correspondence:
| | - Lorena Mosca
- Medical Genetics Unit, ASST Grande Ospedale Metropolitano Niguarda, Piazza Ospedale Maggiore 3, 20162 Milano, Italy;
| | - Valeria Ada Sansone
- The NEMO Clinical Center in Milan, Neurorehabilitation Unit, University of Milan, Piazza Ospedale Maggiore 3, 20162 Milano, Italy;
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Abstract
Neuromuscular disorders (NMDs) comprise a heterogeneous group of disorders that affect about one in every thousand individuals worldwide. The vast majority of NMDs has a genetic cause, with about 600 genes already identified. Application of genetic testing in NMDs can be useful for several reasons: correct diagnostic definition of a proband, extensive familial counselling to identify subjects at risk, and prenatal diagnosis to prevent the recurrence of the disease; furthermore, identification of specific genetic mutations still remains mandatory in some cases for clinical trial enrollment where new gene therapies are now approaching. Even though genetic analysis is catching on in the neuromuscular field, pitfalls and hurdles still remain and they should be taken into account by clinicians, as for example the use of next generation sequencing (NGS) where many single nucleotide variants of "unknown significance" can emerge, complicating the correct interpretation of genotype-phenotype relationship. Finally, when all efforts in terms of molecular analysis have been carried on, a portion of patients affected by NMDs still remain "not genetically defined". In the present review we analyze the evolution of genetic techniques, from Sanger sequencing to NGS, and we discuss "facilitations and hurdles" of genetic testing which must always be balanced by clinicians, in order to ensure a correct diagnostic definition, but taking always into account the benefit that the patient could obtain especially in terms of "therapeutic offer".
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Affiliation(s)
- Andrea Barp
- The NEMO Clinical Center in Milan, Neurorehabilitation Unit, University of Milan, Piazza Ospedale Maggiore 3, 20162 Milano, Italy
| | - Lorena Mosca
- Medical Genetics Unit, ASST Grande Ospedale Metropolitano Niguarda, Piazza Ospedale Maggiore 3, 20162 Milano, Italy
| | - Valeria Ada Sansone
- The NEMO Clinical Center in Milan, Neurorehabilitation Unit, University of Milan, Piazza Ospedale Maggiore 3, 20162 Milano, Italy
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Alston CL, Stenton SL, Hudson G, Prokisch H, Taylor RW. The genetics of mitochondrial disease: dissecting mitochondrial pathology using multi-omic pipelines. J Pathol 2021; 254:430-442. [PMID: 33586140 PMCID: PMC8600955 DOI: 10.1002/path.5641] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/07/2021] [Accepted: 02/09/2021] [Indexed: 12/12/2022]
Abstract
Mitochondria play essential roles in numerous metabolic pathways including the synthesis of adenosine triphosphate through oxidative phosphorylation. Clinically, mitochondrial diseases occur when there is mitochondrial dysfunction – manifesting at any age and affecting any organ system; tissues with high energy requirements, such as muscle and the brain, are often affected. The clinical heterogeneity is parallel to the degree of genetic heterogeneity associated with mitochondrial dysfunction. Around 10% of human genes are predicted to have a mitochondrial function, and defects in over 300 genes are reported to cause mitochondrial disease. Some involve the mitochondrial genome (mtDNA), but the vast majority occur within the nuclear genome. Except for a few specific genetic defects, there remains no cure for mitochondrial diseases, which means that a genetic diagnosis is imperative for genetic counselling and the provision of reproductive options for at‐risk families. Next‐generation sequencing strategies, particularly exome and whole‐genome sequencing, have revolutionised mitochondrial diagnostics such that the traditional muscle biopsy has largely been replaced with a minimally‐invasive blood sample for an unbiased approach to genetic diagnosis. Where these genomic approaches have not identified a causative defect, or where there is insufficient support for pathogenicity, additional functional investigations are required. The application of supplementary ‘omics’ technologies, including transcriptomics, proteomics, and metabolomics, has the potential to greatly improve diagnostic strategies. This review aims to demonstrate that whilst a molecular diagnosis can be achieved for many cases through next‐generation sequencing of blood DNA, the use of patient tissues and an integrated, multidisciplinary multi‐omics approach is pivotal for the diagnosis of more challenging cases. Moreover, the analysis of clinically relevant tissues from affected individuals remains crucial for understanding the molecular mechanisms underlying mitochondrial pathology. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Charlotte L Alston
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,NHS Highly Specialised Services for Rare Mitochondrial Disorders, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Sarah L Stenton
- Institute of Human Genetics, Technische Universität München, München, Germany.,Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Gavin Hudson
- Wellcome Centre for Mitochondrial Research, Bioscience Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Holger Prokisch
- Institute of Human Genetics, Technische Universität München, München, Germany.,Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,NHS Highly Specialised Services for Rare Mitochondrial Disorders, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
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Abstract
Mitochondrial disorders are monogenic disorders characterized by a defect in oxidative phosphorylation and caused by pathogenic variants in one of over 340 different genes. The implementation of whole-exome sequencing has led to a revolution in their diagnosis, duplicated the number of associated disease genes, and significantly increased the diagnosed fraction. However, the genetic etiology of a substantial fraction of patients exhibiting mitochondrial disorders remains unknown, highlighting limitations in variant detection and interpretation, which calls for improved computational and DNA sequencing methods, as well as the addition of OMICS tools. More intriguingly, this also suggests that some pathogenic variants lie outside of the protein-coding genes and that the mechanisms beyond the Mendelian inheritance and the mtDNA are of relevance. This review covers the current status of the genetic basis of mitochondrial diseases, discusses current challenges and perspectives, and explores the contribution of factors beyond the protein-coding regions and monogenic inheritance in the expansion of the genetic spectrum of disease.
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Affiliation(s)
- Mirjana Gusic
- Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute of Human Genetics, Technical University of Munich, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Germany
| | - Holger Prokisch
- Institute of Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute of Human Genetics, Technical University of Munich, Germany
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Hock DH, Robinson DRL, Stroud DA. Blackout in the powerhouse: clinical phenotypes associated with defects in the assembly of OXPHOS complexes and the mitoribosome. Biochem J 2020; 477:4085-132. [PMID: 33151299 DOI: 10.1042/BCJ20190767] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/29/2020] [Accepted: 10/05/2020] [Indexed: 12/26/2022]
Abstract
Mitochondria produce the bulk of the energy used by almost all eukaryotic cells through oxidative phosphorylation (OXPHOS) which occurs on the four complexes of the respiratory chain and the F1–F0 ATPase. Mitochondrial diseases are a heterogenous group of conditions affecting OXPHOS, either directly through mutation of genes encoding subunits of OXPHOS complexes, or indirectly through mutations in genes encoding proteins supporting this process. These include proteins that promote assembly of the OXPHOS complexes, the post-translational modification of subunits, insertion of cofactors or indeed subunit synthesis. The latter is important for all 13 of the proteins encoded by human mitochondrial DNA, which are synthesised on mitochondrial ribosomes. Together the five OXPHOS complexes and the mitochondrial ribosome are comprised of more than 160 subunits and many more proteins support their biogenesis. Mutations in both nuclear and mitochondrial genes encoding these proteins have been reported to cause mitochondrial disease, many leading to defective complex assembly with the severity of the assembly defect reflecting the severity of the disease. This review aims to act as an interface between the clinical and basic research underpinning our knowledge of OXPHOS complex and ribosome assembly, and the dysfunction of this process in mitochondrial disease.
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40
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Affiliation(s)
- Audrey C Woerner
- Department of Medical Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA; UPMC Children's Hospital, Pittsburgh, PA
| | - Jerry Vockley
- Department of Medical Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA; UPMC Children's Hospital, Pittsburgh, PA; University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA.
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Filograna R, Mennuni M, Alsina D, Larsson NG. Mitochondrial DNA copy number in human disease: the more the better? FEBS Lett 2020; 595:976-1002. [PMID: 33314045 PMCID: PMC8247411 DOI: 10.1002/1873-3468.14021] [Citation(s) in RCA: 180] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/02/2020] [Accepted: 11/26/2020] [Indexed: 12/19/2022]
Abstract
Most of the genetic information has been lost or transferred to the nucleus during the evolution of mitochondria. Nevertheless, mitochondria have retained their own genome that is essential for oxidative phosphorylation (OXPHOS). In mammals, a gene‐dense circular mitochondrial DNA (mtDNA) of about 16.5 kb encodes 13 proteins, which constitute only 1% of the mitochondrial proteome. Mammalian mtDNA is present in thousands of copies per cell and mutations often affect only a fraction of them. Most pathogenic human mtDNA mutations are recessive and only cause OXPHOS defects if present above a certain critical threshold. However, emerging evidence strongly suggests that the proportion of mutated mtDNA copies is not the only determinant of disease but that also the absolute copy number matters. In this review, we critically discuss current knowledge of the role of mtDNA copy number regulation in various types of human diseases, including mitochondrial disorders, neurodegenerative disorders and cancer, and during ageing. We also provide an overview of new exciting therapeutic strategies to directly manipulate mtDNA to restore OXPHOS in mitochondrial diseases.
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Affiliation(s)
- Roberta Filograna
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Mara Mennuni
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - David Alsina
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Nils-Göran Larsson
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
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42
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Montano V, Gruosso F, Simoncini C, Siciliano G, Mancuso M. Clinical features of mtDNA-related syndromes in adulthood. Arch Biochem Biophys 2020; 697:108689. [PMID: 33227288 DOI: 10.1016/j.abb.2020.108689] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 11/06/2020] [Accepted: 11/15/2020] [Indexed: 01/26/2023]
Abstract
Mitochondrial diseases are the most common inheritable metabolic diseases, due to defects in oxidative phosphorylation. They are caused by mutations of nuclear or mitochondrial DNA in genes involved in mitochondrial function. The peculiarity of "mitochondrial DNA genetics rules" in part explains the marked phenotypic variability, the complexity of genotype-phenotype correlations and the challenge of genetic counseling. The new massive genetic sequencing technologies have changed the diagnostic approach, enhancing mitochondrial DNA-related syndromes diagnosis and often avoiding the need of a tissue biopsy. Here we present the most common phenotypes associated with a mitochondrial DNA mutation with the recent advances in diagnosis and in therapeutic perspectives.
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Affiliation(s)
- V Montano
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - F Gruosso
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - C Simoncini
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - G Siciliano
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - M Mancuso
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy.
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Alahmad A, Nasca A, Heidler J, Thompson K, Oláhová M, Legati A, Lamantea E, Meisterknecht J, Spagnolo M, He L, Alameer S, Hakami F, Almehdar A, Ardissone A, Alston CL, McFarland R, Wittig I, Ghezzi D, Taylor RW. Bi-allelic pathogenic variants in NDUFC2 cause early-onset Leigh syndrome and stalled biogenesis of complex I. EMBO Mol Med 2020; 12:e12619. [PMID: 32969598 PMCID: PMC7645371 DOI: 10.15252/emmm.202012619] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 08/14/2020] [Accepted: 08/26/2020] [Indexed: 01/13/2023] Open
Abstract
Leigh syndrome is a progressive neurodegenerative disorder, most commonly observed in paediatric mitochondrial disease, and is often associated with pathogenic variants in complex I structural subunits or assembly factors resulting in isolated respiratory chain complex I deficiency. Clinical heterogeneity has been reported, but key diagnostic findings are developmental regression, elevated lactate and characteristic neuroimaging abnormalities. Here, we describe three affected children from two unrelated families who presented with Leigh syndrome due to homozygous variants (c.346_*7del and c.173A>T p.His58Leu) in NDUFC2, encoding a complex I subunit. Biochemical and functional investigation of subjects’ fibroblasts confirmed a severe defect in complex I activity, subunit expression and assembly. Lentiviral transduction of subjects’ fibroblasts with wild‐type NDUFC2 cDNA increased complex I assembly supporting the association of the identified NDUFC2 variants with mitochondrial pathology. Complexome profiling confirmed a loss of NDUFC2 and defective complex I assembly, revealing aberrant assembly intermediates suggestive of stalled biogenesis of the complex I holoenzyme and indicating a crucial role for NDUFC2 in the assembly of the membrane arm of complex I, particularly the ND2 module.
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Affiliation(s)
- Ahmad Alahmad
- Wellcome Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK.,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,Kuwait Medical Genetics Centre, Al-Sabah Medical Area, Kuwait
| | - Alessia Nasca
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Juliana Heidler
- SFB815 Core Unit, Functional Proteomics, Medical School, Goethe-Universität, Frankfurt am Main, Germany
| | - Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK.,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Monika Oláhová
- Wellcome Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK.,Faculty of Medical Sciences, Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Andrea Legati
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Eleonora Lamantea
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Jana Meisterknecht
- SFB815 Core Unit, Functional Proteomics, Medical School, Goethe-Universität, Frankfurt am Main, Germany
| | - Manuela Spagnolo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Langping He
- Wellcome Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK.,NHS Highly Specialised Service for Rare Mitochondrial Disorders, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Seham Alameer
- Pediatric Department, Ministry of National Guard Health Affairs, Jeddah, Saudi Arabia.,King Abdullah International Medical Research Center, Jeddah, Saudi Arabia.,King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Fahad Hakami
- Section of Molecular Medicine, King Abdulaziz Medical City-WR, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Abeer Almehdar
- Department of Medical Imaging, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City-WR, National Guard Health Affairs, Jeddah, Saudi Arabia
| | - Anna Ardissone
- Child Neurology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Charlotte L Alston
- Wellcome Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK.,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,NHS Highly Specialised Service for Rare Mitochondrial Disorders, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK.,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,NHS Highly Specialised Service for Rare Mitochondrial Disorders, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Ilka Wittig
- SFB815 Core Unit, Functional Proteomics, Medical School, Goethe-Universität, Frankfurt am Main, Germany.,German Center for Cardiovascular Research (DZHK), Partner site RheinMain, Frankfurt, Germany
| | - Daniele Ghezzi
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.,Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK.,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,NHS Highly Specialised Service for Rare Mitochondrial Disorders, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
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Barcia G, Assouline Z, Magen M, Pennisi A, Rötig A, Munnich A, Bonnefont JP, Steffann J. Improving post-natal detection of mitochondrial DNA mutations. Expert Rev Mol Diagn 2020; 20:1003-1008. [PMID: 32902337 DOI: 10.1080/14737159.2020.1820326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Currently, genetic testing of mitochondrial DNA mutations includes screening for single-nucleotide variants, several base pair insertions or deletions, large-scale deletions, or relative depletion of total mitochondrial DNA content. Within the last decade, next-generation sequencing (NGS) has resulted in remarkable advances in the field of mitochondrial diseases (MD) and has become a routine step of the diagnostic workup. AREAS COVERED We aimed to present an overview of current technologies employed in molecular diagnosis of mitochondrial DNA diseases. We report on the recent contributions of NGS testing to the diagnosis and understanding of MD. EXPERT OPINION The progress of NGS technologies allows the simultaneous detection of mutations and quantification of the heteroplasmy level, ensuring sensitivity and specificity requested for the detection of mitochondrial DNA point mutations. NGS protocols enabling the simultaneous analysis of mitochondrial and nuclear DNA are now efficient and cost-saving approaches, and have become the gold-standard technique in diagnostic laboratories.
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Affiliation(s)
- Giulia Barcia
- Université de Paris et Service de Génétique Moléculaire, Reference Center for Mitochondrial Diseases (CARAMMEL), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris , Paris, France
| | - Zahra Assouline
- Université de Paris et Service de Génétique Moléculaire, Reference Center for Mitochondrial Diseases (CARAMMEL), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris , Paris, France
| | - Maryse Magen
- Université de Paris et Service de Génétique Moléculaire, Reference Center for Mitochondrial Diseases (CARAMMEL), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris , Paris, France
| | - Alessandra Pennisi
- Université de Paris et Service de Génétique Moléculaire, Reference Center for Mitochondrial Diseases (CARAMMEL), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris , Paris, France.,Laboratory for Genetics of Mitochondrial Disorders, INSERM U1163, Université Paris Descartes-Sorbonne Paris Cité, Institut Imagine , Paris, France
| | - Agnès Rötig
- Laboratory for Genetics of Mitochondrial Disorders, INSERM U1163, Université Paris Descartes-Sorbonne Paris Cité, Institut Imagine , Paris, France
| | - Arnold Munnich
- Université de Paris et Service de Génétique Moléculaire, Reference Center for Mitochondrial Diseases (CARAMMEL), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris , Paris, France.,Laboratory for Genetics of Mitochondrial Disorders, INSERM U1163, Université Paris Descartes-Sorbonne Paris Cité, Institut Imagine , Paris, France
| | - Jean-Paul Bonnefont
- Université de Paris et Service de Génétique Moléculaire, Reference Center for Mitochondrial Diseases (CARAMMEL), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris , Paris, France.,Laboratory for Genetics of Mitochondrial Disorders, INSERM U1163, Université Paris Descartes-Sorbonne Paris Cité, Institut Imagine , Paris, France
| | - Julie Steffann
- Université de Paris et Service de Génétique Moléculaire, Reference Center for Mitochondrial Diseases (CARAMMEL), Groupe Hospitalier Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris , Paris, France.,Laboratory for Genetics of Mitochondrial Disorders, INSERM U1163, Université Paris Descartes-Sorbonne Paris Cité, Institut Imagine , Paris, France
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45
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Tsang MHY, Kwong AKY, Chan KLS, Fung JLF, Yu MHC, Mak CCY, Yeung KS, Rodenburg RJT, Smeitink JAM, Chan R, Tsoi T, Hui J, Wong SSN, Tai SM, Chan VCM, Ma CK, Fung STH, Wu SP, Chak WK, Chung BHY, Fung CW. Delineation of molecular findings by whole-exome sequencing for suspected cases of paediatric-onset mitochondrial diseases in the Southern Chinese population. Hum Genomics 2020; 14:28. [PMID: 32907636 PMCID: PMC7488033 DOI: 10.1186/s40246-020-00278-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/27/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Mitochondrial diseases (MDs) are a group of clinically and genetically heterogeneous disorders characterized by defects in oxidative phosphorylation. Since clinical phenotypes of MDs may be non-specific, genetic diagnosis is crucial for guiding disease management. In the current study, whole-exome sequencing (WES) was performed for our paediatric-onset MD cohort of a Southern Chinese origin, with the aim of identifying key disease-causing variants in the Chinese patients with MDs. METHODS We recruited Chinese patients who had paediatric-onset MDs and a minimum mitochondrial disease criteria (MDC) score of 3. Patients with positive target gene or mitochondrial DNA sequencing results were excluded. WES was performed, variants with population frequency ≤ 1% were analysed for pathogenicity on the basis of the American College of Medical Genetics and Genomics guidelines. RESULTS Sixty-six patients with pre-biopsy MDC scores of 3-8 were recruited. The overall diagnostic yield was 35% (23/66). Eleven patients (17%) were found to have mutations in MD-related genes, with COQ4 having the highest mutation rate owing to the Chinese-specific founder mutation (4/66, 6%). Twelve patients (12/66, 18%) had mutations in non-MD-related genes: ATP1A3 (n = 3, two were siblings), ALDH5A1, ARX, FA2H, KCNT1, LDHD, NEFL, NKX2-2, TBCK, and WAC. CONCLUSIONS We confirmed that the COQ4:c.370G>A, p.(Gly124Ser) variant, was a founder mutation among the Southern Chinese population. Screening for this mutation should therefore be considered while diagnosing Chinese patients suspected to have MDs. Furthermore, WES has proven to be useful in detecting variants in patients suspected to have MDs because it helps to obtain an unbiased and precise genetic diagnosis for these diseases, which are genetically heterogeneous.
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Affiliation(s)
- Mandy H Y Tsang
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Anna K Y Kwong
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Kate L S Chan
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Jasmine L F Fung
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Mullin H C Yu
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Christopher C Y Mak
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Kit-San Yeung
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Richard J T Rodenburg
- Radboud Center for Mitochondrial Medicine, Department of Paediatrics, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jan A M Smeitink
- Radboud Center for Mitochondrial Medicine, Department of Paediatrics, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Rachel Chan
- Department of Paediatrics, Centro Hospitalar Conde de São Januário (CHCSJ) Hospital, SAR, Macau, China
| | - Thomas Tsoi
- Department of Paediatrics, Centro Hospitalar Conde de São Januário (CHCSJ) Hospital, SAR, Macau, China
| | - Joannie Hui
- Department of Paediatrics and Adolescent Medicine, Hong Kong Children's Hospital, Doctors' Office, 9/F, Tower B, 1 Shing Cheong Road, Kowloon Bay, Kowloon, Hong Kong, SAR, China
| | - Shelia S N Wong
- Department of Paediatrics and Adolescent Medicine, Hong Kong Children's Hospital, Doctors' Office, 9/F, Tower B, 1 Shing Cheong Road, Kowloon Bay, Kowloon, Hong Kong, SAR, China
| | - Shuk-Mui Tai
- Department of Paediatrics & Adolescent Medicine, Pamela Youde Nethersole Eastern Hospital, Hong Kong, SAR, China
| | - Victor C M Chan
- Department of Paediatrics & Adolescent Medicine, Pamela Youde Nethersole Eastern Hospital, Hong Kong, SAR, China
| | - Che-Kwan Ma
- Department of Paediatrics and Adolescent Medicine, United Christian Hospital, Hong Kong, SAR, China
| | - Sharon T H Fung
- Department of Paediatrics, Kwong Wah Hospital, Hong Kong, SAR, China
| | - Shun-Ping Wu
- Department of Paediatrics and Adolescent Medicine, Queen Elizabeth Hospital, Hong Kong, SAR, China
| | - W K Chak
- Department of Paediatrics and Adolescent Medicine, Tuen Mun Hospital, Hong Kong, SAR, China
| | - Brian H Y Chung
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China. .,Department of Paediatrics and Adolescent Medicine, Hong Kong Children's Hospital, Doctors' Office, 9/F, Tower B, 1 Shing Cheong Road, Kowloon Bay, Kowloon, Hong Kong, SAR, China. .,Department of Pediatrics and Adolescent Medicine, Queen Mary Hospital, Room 115, 1/F, New Clinical Building, 102 Pokfulam Road, Hong Kong, SAR, China. .,Department of Paediatrics & Adolescent Medicine, Duchess of Kent Children's Hospital, Hong Kong, SAR, China.
| | - Cheuk-Wing Fung
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China. .,Department of Paediatrics and Adolescent Medicine, Hong Kong Children's Hospital, Doctors' Office, 9/F, Tower B, 1 Shing Cheong Road, Kowloon Bay, Kowloon, Hong Kong, SAR, China.
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46
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Schon KR, Ratnaike T, van den Ameele J, Horvath R, Chinnery PF. Mitochondrial Diseases: A Diagnostic Revolution. Trends Genet 2020; 36:702-717. [PMID: 32674947 DOI: 10.1016/j.tig.2020.06.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 12/26/2022]
Abstract
Mitochondrial disorders have emerged as a common cause of inherited disease, but are traditionally viewed as being difficult to diagnose clinically, and even more difficult to comprehensively characterize at the molecular level. However, new sequencing approaches, particularly whole-genome sequencing (WGS), have dramatically changed the landscape. The combined analysis of nuclear and mitochondrial DNA (mtDNA) allows rapid diagnosis for the vast majority of patients, but new challenges have emerged. We review recent discoveries that will benefit patients and families, and highlight emerging questions that remain to be resolved.
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Affiliation(s)
- Katherine R Schon
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK; Medical Research Council (MRC) Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Thiloka Ratnaike
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK; Medical Research Council (MRC) Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK; Department of Paediatrics, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Jelle van den Ameele
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK; Medical Research Council (MRC) Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Rita Horvath
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Patrick F Chinnery
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK; Medical Research Council (MRC) Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
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47
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Kerr M, Hume S, Omar F, Koo D, Barnes H, Khan M, Aman S, Wei XC, Alfuhaid H, McDonald R, McDonald L, Newell C, Sparkes R, Hittel D, Khan A. MITO-FIND: A study in 390 patients to determine a diagnostic strategy for mitochondrial disease. Mol Genet Metab 2020; 131:66-82. [PMID: 32980267 DOI: 10.1016/j.ymgme.2020.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/29/2020] [Accepted: 08/30/2020] [Indexed: 12/14/2022]
Abstract
Mitochondrial diseases, due to nuclear or mitochondrial genome mutations causing mitochondrial dysfunction, have a wide range of clinical features involving neurologic, muscular, cardiac, hepatic, visual, and auditory symptoms. Making a diagnosis of a mitochondrial disease is often challenging since there is no gold standard and traditional testing methods have required tissue biopsy which presents technical challenges and most patients prefer a non-invasive approach. Since a diagnosis invariably involves finding a disease-causing DNA variant, new approaches such as next generation sequencing (NGS) have the potential to make it easier to make a diagnosis. We evaluated the ability of our traditional diagnostic pathway (metabolite analysis, tissue neuropathology and respiratory chain enzyme activity) in 390 patients. The traditional diagnostic pathway provided a diagnosis of mitochondrial disease in 115 patients (29.50%). Analysis of mtDNA, tissue neuropathology, skin electron microscopy, respiratory chain enzyme analysis using inhibitor assays, blue native polyacrylamide gel electrophoresis were all statistically significant in distinguishing patients between a mitochondrial and non-mitochondrial diagnosis. From these 390 patients who underwent traditional analysis, we recruited 116 patients for the NGS part of the study (36 patients who had a mitochondrial diagnosis (MITO) and 80 patients who had no diagnosis (No-Dx)). In the group of 36 MITO patients, nuclear whole exome sequencing (nWES) provided a second diagnosis in 2 cases who already had a pathogenic variant in mtDNA, and a revised diagnosis (GLUL) in one case that had abnormal pathology but no pathogenic mtDNA variant. In the 80 NO-Dx patients, nWES found non-mitochondrial diagnosis in 26 patients and a mitochondrial diagnosis in 1 patient. A genetic diagnosis was obtained in 53/116 (45.70%) cases that were recruited for NGS, but not in 11/116 (9.48%) of cases with abnormal mitochondrial neuropathology. Our results show that a non-invasive, bigenomic sequencing (BGS) approach (using both a nWES and optimized mtDNA analysis to include large deletions) should be the first step in investigating for mitochondrial diseases. There may still be a role for tissue biopsy in unsolved cases or when the diagnosis is still not clear after NGS studies.
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Affiliation(s)
- Marina Kerr
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Stacey Hume
- Department of Medical Genetics, University of Alberta, Edmonton, Canada
| | - Fadya Omar
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Desmond Koo
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Heather Barnes
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Maida Khan
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Suhaib Aman
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Xing-Chang Wei
- Department of Radiology, Alberta Children's Hospital, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
| | - Hanen Alfuhaid
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Roman McDonald
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Liam McDonald
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Christopher Newell
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Rebecca Sparkes
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Dustin Hittel
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Aneal Khan
- Departments of Medical Genetics and Pediatrics, University of Calgary Cumming School of Medicine, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada.
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48
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Kamatani N. Genes, the brain, and artificial intelligence in evolution. J Hum Genet 2021; 66:103-9. [PMID: 32719359 DOI: 10.1038/s10038-020-0813-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/09/2020] [Accepted: 07/19/2020] [Indexed: 11/08/2022]
Abstract
Three important systems, genes, the brain, and artificial intelligence (especially deep learning) have similar goals, namely, the maximization of likelihood or minimization of cross-entropy. Animal brains have evolved through predator-prey interactions in which maximizing survival probability and transmission of genes to offspring were the main objectives. Coordinate transformation for a rigid body necessary to win predator-prey battles requires a huge amount of matrix operations in the brain similar to those performed by a powerful GPU. Things (molecules), information (genes), and energy (ATP) are essential for using Maxwell's demon model to understand how a living system maintains a low level of entropy. However, while the history of medicine and biology saw molecular biology and genetics disciplines flourish, the study of energy has been limited, despite estimates that >10% all human genes code energy-related proteins. Since there are a large number of molecular and genetic diseases, many energy-related diseases must exist as well. In addition to mitochondrial disease, common diseases such as neurodegenerative diseases, muscle diseases, cardiomyopathy, and diabetes are candidates for diseases related to cellular energy shortage. We are developing ATP enhancer, a drug to treat such diseases. I predict that in the future, the frontier of medicine and biology will involve energy and entropy, and the frontier of science will be about the cognitive processes that scientists' brains use to study mathematics and physics. That will be understood by comparing the abilities that were necessary to survive battles between predators and prey during evolutionary history.
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Marchet S, Legati A, Nasca A, Di Meo I, Spagnolo M, Zanetti N, Lamantea E, Catania A, Lamperti C, Ghezzi D. Homozygous mutations in C1QBP as cause of progressive external ophthalmoplegia (PEO) and mitochondrial myopathy with multiple mtDNA deletions. Hum Mutat 2020; 41:1745-1750. [PMID: 32652806 DOI: 10.1002/humu.24081] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/05/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022]
Abstract
Biallelic mutations in the C1QBP gene have been associated with mitochondrial cardiomyopathy and combined respiratory-chain deficiencies, with variable onset (including intrauterine or neonatal forms), phenotypes, and severity. We studied two unrelated adult patients from consanguineous families, presenting with progressive external ophthalmoplegia (PEO), mitochondrial myopathy, and without any heart involvement. Muscle biopsies from both patients showed typical mitochondrial alterations and the presence of multiple mitochondrial DNA deletions, whereas biochemical defects of the respiratory chain were present only in one subject. Using next-generation sequencing approaches, we identified homozygous mutations in C1QBP. Immunoblot analyses in patients' muscle samples revealed a strong reduction in the amount of the C1QBP protein and varied impairment of respiratory chain complexes, correlating with disease severity. Despite the original study indicated C1QBP mutations as causative for mitochondrial cardiomyopathy, our data indicate that mutations in C1QBP have to be considered in subjects with PEO phenotype or primary mitochondrial myopathy and without cardiomyopathy.
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Affiliation(s)
- Silvia Marchet
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Andrea Legati
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Alessia Nasca
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Ivano Di Meo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Manuela Spagnolo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Nadia Zanetti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Eleonora Lamantea
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Alessia Catania
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Costanza Lamperti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Daniele Ghezzi
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy.,Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milano, Italy
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50
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du Mee DJM, Bak M, Østergaard E, Rasmussen LJ. Mitochondrial dysfunction induced by variation in the non-coding genome - A proposed workflow to improve diagnostics. Mitochondrion 2020; 53:255-259. [PMID: 32497723 DOI: 10.1016/j.mito.2020.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/26/2020] [Indexed: 11/18/2022]
Abstract
Mitochondrial disorders are one of the most common inherited metabolic disorders and are caused by variants in nuclear genes or the mitochondrial genome. Additionally, there is a large group of patients displaying clinical symptoms, where the genetic background is unknown. Mitochondrial disorders have a huge variety in their clinical presentation, making diagnostics challenging. Genomes of higher organisms contain around 95% non-protein-coding DNA. Recently, non-protein-coding sequences have been shown to affect gene expression in many cellular processes, including mitochondrial functioning. As these insights are not frequently incorporated in diagnostics we propose a workflow utilizing this knowledge for faster diagnostics of patients lacking a molecular diagnosis.
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Affiliation(s)
- Dorine Jeanne Mariëtte du Mee
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark
| | - Mads Bak
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Elsebet Østergaard
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Lene Juel Rasmussen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Denmark.
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