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Mathis D, Koch J, Koller S, Sauter K, Flück C, Uldry AC, Forny P, Froese DS, Laemmle A. Induced pluripotent stem cell-derived hepatocytes reveal TCA cycle disruption and the potential basis for triheptanoin treatment for malate dehydrogenase 2 deficiency. Mol Genet Metab Rep 2024; 39:101066. [PMID: 38425868 PMCID: PMC10900122 DOI: 10.1016/j.ymgmr.2024.101066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/02/2024] Open
Abstract
Mitochondrial malate dehydrogenase 2 (MDH2) is crucial to cellular energy generation through direct participation in the tricarboxylic acid (TCA) cycle and the malate aspartate shuttle (MAS). Inherited MDH2 deficiency is an ultra-rare metabolic disease caused by bi-allelic pathogenic variants in the MDH2 gene, resulting in early-onset encephalopathy, psychomotor delay, muscular hypotonia and frequent seizures. Currently, there is no cure for this devastating disease. We recently reported symptomatic improvement of a three-year-old girl with MDH2 deficiency following treatment with the triglyceride triheptanoin. Here, we aimed to better characterize this disease and improve our understanding of the potential utility of triheptanoin treatment. Using fibroblasts derived from this patient, we generated induced pluripotent stem cells (hiPSCs) and differentiated them into hepatocytes (hiPSC-Heps). Characterization of patient-derived hiPSCs and hiPSC-Heps revealed significantly reduced MDH2 protein expression. Untargeted proteotyping of hiPSC-Heps revealed global dysregulation of mitochondrial proteins, including upregulation of TCA cycle and fatty acid oxidation enzymes. Metabolomic profiling confirmed TCA cycle and MAS dysregulation, and demonstrated normalization of malate, fumarate and aspartate following treatment with the triheptanoin components glycerol and heptanoate. Taken together, our results provide the first patient-derived hiPSC-Hep-based model of MDH2 deficiency, confirm altered TCA cycle function, and provide further evidence for the implementation of triheptanoin therapy for this ultra-rare disease. Synopsis This study reveals altered expression of mitochondrial pathways including the tricarboxylic acid cycle and changes in metabolite profiles in malate dehydrogenase 2 deficiency and provides the molecular basis for triheptanoin treatment in this ultra-rare disease.
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Affiliation(s)
- Déborah Mathis
- University Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Jasmine Koch
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Sophie Koller
- University Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Switzerland
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Pharmacy, Medical Faculty, University of Bern, Bern, Switzerland
| | - Kay Sauter
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Christa Flück
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Anne-Christine Uldry
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Patrick Forny
- Division of Metabolism and Children's Research Center, University Children's Hospital, University of Zurich, Zurich, Switzerland
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
| | - D. Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital, University of Zurich, Zurich, Switzerland
| | - Alexander Laemmle
- University Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Switzerland
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Lancaster MS, Kim B, Doud EH, Tate MD, Sharify AD, Gao H, Chen D, Simpson E, Gillespie P, Chu X, Miller MJ, Wang Y, Liu Y, Mosley AL, Kim J, Graham BH. Loss of succinyl-CoA synthetase in mouse forebrain results in hypersuccinylation with perturbed neuronal transcription and metabolism. Cell Rep 2023; 42:113241. [PMID: 37819759 PMCID: PMC10683835 DOI: 10.1016/j.celrep.2023.113241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/24/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023] Open
Abstract
Lysine succinylation is a subtype of protein acylation associated with metabolic regulation of succinyl-CoA in the tricarboxylic acid cycle. Deficiency of succinyl-CoA synthetase (SCS), the tricarboxylic acid cycle enzyme catalyzing the interconversion of succinyl-CoA to succinate, results in mitochondrial encephalomyopathy in humans. This report presents a conditional forebrain-specific knockout (KO) mouse model of Sucla2, the gene encoding the ATP-specific beta isoform of SCS, resulting in postnatal deficiency of the entire SCS complex. Results demonstrate that accumulation of succinyl-CoA in the absence of SCS leads to hypersuccinylation within the murine cerebral cortex. Specifically, increased succinylation is associated with functionally significant reduced activity of respiratory chain complex I and widescale alterations in chromatin landscape and gene expression. Integrative analysis of the transcriptomic data also reveals perturbations in regulatory networks of neuronal transcription in the KO forebrain. Together, these findings provide evidence that protein succinylation plays a significant role in the pathogenesis of SCS deficiency.
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Affiliation(s)
- Makayla S Lancaster
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Byungwook Kim
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Emma H Doud
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Mason D Tate
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ahmad D Sharify
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Hongyu Gao
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Duojiao Chen
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ed Simpson
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Patrick Gillespie
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Xiaona Chu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Marcus J Miller
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yue Wang
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yunlong Liu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Jungsu Kim
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Brett H Graham
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Lancaster MS, Graham BH. Succinyl-CoA Synthetase Dysfunction as a Mechanism of Mitochondrial Encephalomyopathy: More than Just an Oxidative Energy Deficit. Int J Mol Sci 2023; 24:10725. [PMID: 37445899 PMCID: PMC10342173 DOI: 10.3390/ijms241310725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/23/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Biallelic pathogenic variants in subunits of succinyl-CoA synthetase (SCS), a tricarboxylic acid (TCA) cycle enzyme, are associated with mitochondrial encephalomyopathy in humans. SCS catalyzes the interconversion of succinyl-CoA to succinate, coupled to substrate-level phosphorylation of either ADP or GDP, within the TCA cycle. SCS-deficient encephalomyopathy typically presents in infancy and early childhood, with many patients succumbing to the disease during childhood. Common symptoms include abnormal brain MRI, basal ganglia lesions and cerebral atrophy, severe hypotonia, dystonia, progressive psychomotor regression, and growth deficits. Although subunits of SCS were first identified as causal genes for progressive metabolic encephalomyopathy in the early 2000s, recent investigations are now beginning to unravel the pathomechanisms underlying this metabolic disorder. This article reviews the current understanding of SCS function within and outside the TCA cycle as it relates to the complex and multifactorial mechanisms underlying SCS-related mitochondrial encephalomyopathy.
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Affiliation(s)
| | - Brett H. Graham
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, 975 W. Walnut St., Room IB257, Indianapolis, IN 46202, USA;
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Mortensen Ó, Thomsen E, Lydersen LN, Apol KD, Weihe P, Steig BÁ, Andorsdóttir G, Als TD, Gregersen NO. FarGen: Elucidating the distribution of coding variants in the isolated population of the Faroe Islands. Eur J Hum Genet 2023; 31:329-337. [PMID: 36404349 PMCID: PMC9995356 DOI: 10.1038/s41431-022-01227-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/30/2022] [Accepted: 10/27/2022] [Indexed: 11/22/2022] Open
Abstract
Here we present results from FarGen Phase I exomes. This dataset is based on the FarGen cohort, which consists of 1,541 individuals from the isolated population of the Faroe Islands. The purpose of this cohort is to serve as a reference catalog of coding variants, and to conduct population genetic studies to better understand the genetic contribution to various diseases in the Faroese population. The first whole-exome data set comprise 465 individuals and a total of 148,267 genetic variants were discovered. Principle Component Analysis indicates that the population is isolated and weakly structured. The distribution of variants in various functional classes was compared with populations in the gnomAD dataset; the results indicated that the proportions were consistent across the cohorts, but probably due to a small sample size, the FarGen dataset contained relatively few rare variants. We identified 19 variants that are classified as pathogenic or likely pathogenic in ClinVar; several of these variants are associated with monogenetic diseases with increased prevalence in the Faroe Islands. The results support previous studies, which indicate that the Faroe Islands is an isolated and weakly structured population. Future studies may elucidate the significance of the 19 pathogenic variants that were identified. The FarGen Phase I dataset is an important step for genetic research in the Faroese population, and the next phase of FarGen will increase the sample size and broaden the scope.
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Affiliation(s)
- Ólavur Mortensen
- The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands
| | - Elisabet Thomsen
- The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands
| | | | - Katrin D Apol
- The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands
| | - Pál Weihe
- Department of Occupational Medicine and Public Health, National Hospital of the Faroe Islands Tórshavn, Tórshavn, Faroe Islands
| | - Bjarni Á Steig
- Medical Department, National Hospital of the Faroe Islands, Tórshavn, Faroe Islands
| | - Guðrið Andorsdóttir
- The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands
- Centre of Health Science, Faculty of Health, University of the Faroe Islands, Tórshavn, Faroe Islands
| | - Thomas D Als
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus, Denmark
- Center for Genomics and Personalized Medicine, Aarhus, Denmark
| | - Noomi O Gregersen
- The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands.
- Centre of Health Science, Faculty of Health, University of the Faroe Islands, Tórshavn, Faroe Islands.
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Abstract
Leigh syndrome, or subacute necrotizing encephalomyelopathy, was initially recognized as a neuropathological entity in 1951. Bilateral symmetrical lesions, typically extending from the basal ganglia and thalamus through brainstem structures to the posterior columns of the spinal cord, are characterized microscopically by capillary proliferation, gliosis, severe neuronal loss, and relative preservation of astrocytes. Leigh syndrome is a pan-ethnic disorder usually with onset in infancy or early childhood, but late-onset forms occur, including in adult life. Over the last six decades it has emerged that this complex neurodegenerative disorder encompasses more than 100 separate monogenic disorders associated with enormous clinical and biochemical heterogeneity. This chapter discusses clinical, biochemical and neuropathological aspects of the disorder, and postulated pathomechanisms. Known genetic causes, including defects of 16 mitochondrial DNA (mtDNA) genes and approaching 100 nuclear genes, are categorized into disorders of subunits and assembly factors of the five oxidative phosphorylation enzymes, disorders of pyruvate metabolism and vitamin and cofactor transport and metabolism, disorders of mtDNA maintenance, and defects of mitochondrial gene expression, protein quality control, lipid remodeling, dynamics, and toxicity. An approach to diagnosis is presented, together with known treatable causes and an overview of current supportive management options and emerging therapies on the horizon.
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Affiliation(s)
- Shamima Rahman
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom; Metabolic Medicine Department, Great Ormond Street Hospital for Children, London, United Kingdom.
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Mitochondrial Neurodegeneration. Cells 2022; 11:cells11040637. [PMID: 35203288 PMCID: PMC8870525 DOI: 10.3390/cells11040637] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 01/28/2022] [Accepted: 02/06/2022] [Indexed: 01/27/2023] Open
Abstract
Mitochondria are cytoplasmic organelles, which generate energy as heat and ATP, the universal energy currency of the cell. This process is carried out by coupling electron stripping through oxidation of nutrient substrates with the formation of a proton-based electrochemical gradient across the inner mitochondrial membrane. Controlled dissipation of the gradient can lead to production of heat as well as ATP, via ADP phosphorylation. This process is known as oxidative phosphorylation, and is carried out by four multiheteromeric complexes (from I to IV) of the mitochondrial respiratory chain, carrying out the electron flow whose energy is stored as a proton-based electrochemical gradient. This gradient sustains a second reaction, operated by the mitochondrial ATP synthase, or complex V, which condensates ADP and Pi into ATP. Four complexes (CI, CIII, CIV, and CV) are composed of proteins encoded by genes present in two separate compartments: the nuclear genome and a small circular DNA found in mitochondria themselves, and are termed mitochondrial DNA (mtDNA). Mutations striking either genome can lead to mitochondrial impairment, determining infantile, childhood or adult neurodegeneration. Mitochondrial disorders are complex neurological syndromes, and are often part of a multisystem disorder. In this paper, we divide the diseases into those caused by mtDNA defects and those that are due to mutations involving nuclear genes; from a clinical point of view, we discuss pediatric disorders in comparison to juvenile or adult-onset conditions. The complementary genetic contributions controlling organellar function and the complexity of the biochemical pathways present in the mitochondria justify the extreme genetic and phenotypic heterogeneity of this new area of inborn errors of metabolism known as ‘mitochondrial medicine’.
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Stenton SL, Zou Y, Cheng H, Liu Z, Wang J, Shen D, Jin H, Ding C, Tang X, Sun S, Han H, Ma Y, Zhang W, Jin R, Wang H, Sun D, Lv JL, Prokisch H, Fang F. Leigh syndrome: a study of 209 patients at the Beijing Children's Hospital. Ann Neurol 2022; 91:466-482. [PMID: 35094435 DOI: 10.1002/ana.26313] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 01/25/2022] [Accepted: 01/27/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Sarah L. Stenton
- Institute of Human Genetics, School of Medicine Technical University of Munich Munich Germany
- Institute of Neurogenomics Helmholtz Zentrum München Neuherberg Germany
| | - Ying Zou
- Department of Neurology, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
| | - Hua Cheng
- Image Center, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
| | - Zhimei Liu
- Department of Neurology, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
| | - Junling Wang
- Department of Neurology, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
| | - Danmin Shen
- Department of Neurology, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
| | - Hong Jin
- Department of Neurology, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
| | - Changhong Ding
- Department of Neurology, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
| | - Xiaolu Tang
- Image Center, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
| | - Suzhen Sun
- Department of Neurology Children's Hospital of Hebei Province Shijiazhuang China
| | - Hong Han
- Department of Neurology Children's Hospital of Shanxi Province Taiyuan China
| | - Yanli Ma
- Department of Neurology Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital Zhengzhou China
| | - Weihua Zhang
- Department of Neurology, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
- Department of Neurology Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital Zhengzhou China
| | - Ruifeng Jin
- Department of Neurology Qilu Children's Hospital of Shandong University Jinan China
| | - Hua Wang
- Department of Pediatrics Shengjing Hospital of China Medical University Shenyang China
| | - Dan Sun
- Department of Neurology Wuhan Children's Hospital Wuhan China
| | - Jun Lan Lv
- Department of Neurology, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
| | - Holger Prokisch
- Institute of Human Genetics, School of Medicine Technical University of Munich Munich Germany
- Institute of Neurogenomics Helmholtz Zentrum München Neuherberg Germany
| | - Fang Fang
- Department of Neurology, National Center for Children's Health, Beijing Children's Hospital Capital Medical University Beijing China
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8
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Lim AZ, Ng YS, Blain A, Jiminez-Moreno C, Alston CL, Nesbitt V, Simmons L, Santra S, Wassmer E, Blakely EL, Turnbull DM, Taylor RW, Gorman GS, McFarland R. Natural History of Leigh Syndrome: A Study of Disease Burden and Progression. Ann Neurol 2021; 91:117-130. [PMID: 34716721 PMCID: PMC9534328 DOI: 10.1002/ana.26260] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 11/21/2022]
Abstract
Objective This observational cohort study aims to quantify disease burden over time, establish disease progression rates, and identify factors that may determine the disease course of Leigh syndrome. Methods Seventy‐two Leigh syndrome children who completed the Newcastle Paediatric Mitochondrial Disease Scale (NPMDS) at baseline at 3.7 years (interquartile range [IQR] = 2.0–7.6) and follow‐up assessments at 7.5 years (IQR = 3.7–11.0) in clinics were enrolled. Eighty‐two percent of this cohort had a confirmed genetic diagnosis, with pathogenic variants in the MT‐ATP6 and SURF1 genes being the most common cause. The total NPMDS scores denoted mild (0–14), moderate (15–25), and severe (>25) disease burden. Detailed clinical, neuroradiological, and molecular genetic findings were also analyzed. Results The median total NPMDS scores rose significantly (Z = −6.9, p < 0.001), and the percentage of children with severe disease burden doubled (22% → 42%) over 2.6 years of follow‐up. Poor function (especially mobility, self‐care, communication, feeding, and education) and extrapyramidal features contributed significantly to the disease burden (τb ≈ 0.45–0.68, p < 0.001). These children also deteriorated to wheelchair dependence (31% → 57%), exclusive enteral feeding (22% → 46%), and one‐to‐one assistance for self‐care (25% → 43%) during the study period. Twelve children (17%) died after their last NPMDS scores were recorded. These children had higher follow‐up NPMDS scores (disease burden; p < 0.001) and steeper increase in NPMDS score per annum (disease progression; p < 0.001). Other predictors of poor outcomes include SURF1 gene variants (p < 0.001) and bilateral caudate changes on neuroimaging (p < 0.01). Interpretation This study has objectively defined the disease burden and progression of Leigh syndrome. Our analysis has also uncovered potential influences on the trajectory of this neurodegenerative condition. ANN NEUROL 2022;91:117–130
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Affiliation(s)
- Albert Z Lim
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,National Health Service Highly Specialised Services for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, UK
| | - Yi Shiau Ng
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,National Health Service Highly Specialised Services for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, UK
| | - Alasdair Blain
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Cecilia Jiminez-Moreno
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Charlotte L Alston
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,National Health Service Highly Specialised Services for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, UK
| | - Victoria Nesbitt
- National Health Service Highly Specialised Services for Rare Mitochondrial Disorders, Oxford University Hospitals National Health Service Foundation Trust, Oxford, UK
| | | | | | | | - Emma L Blakely
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,National Health Service Highly Specialised Services for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, UK
| | - Doug M Turnbull
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,National Health Service Highly Specialised Services for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,National Health Service Highly Specialised Services for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, UK
| | - Gráinne S Gorman
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,National Health Service Highly Specialised Services for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, UK
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,National Health Service Highly Specialised Services for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, UK
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9
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Horton L, Henry M, Conway R, Kumar B. An Intriguing Case of Acute Left-Sided Weakness in a 4-Year-Old Boy. Clin Pediatr (Phila) 2021; 60:432-436. [PMID: 34247546 DOI: 10.1177/00099228211030796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | | | - Robert Conway
- Central Michigan University, Mount Pleasant, MI, USA
| | - Banu Kumar
- Wayne State University, Detroit, MI, USA
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10
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Hsu CL, Iwanowski P, Hsu CH, Kozubski W. Genetic diseases mimicking multiple sclerosis. Postgrad Med 2021; 133:728-749. [PMID: 34152933 DOI: 10.1080/00325481.2021.1945898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Multiple sclerosis (MS) is an inflammatory neurodegenerative disorder manifesting as gradual or progressive loss of neurological functions. Most patients present with relapsing-remitting disease courses. Extensive research over recent decades has expounded our insights into the presentations and diagnostic features of MS. Groups of genetic diseases, CADASIL and leukodystrophies, for example, have been frequently misdiagnosed with MS due to some overlapping clinical and radiological features. The delayed identification of these diseases in late adulthood can lead to severe neurological complications. Herein we discuss genetic diseases that have the potential to mimic multiple sclerosis, with highlights on clinical identification and practicing pearls that may aid physicians in recognizing MS-mimics with genetic background in clinical settings.
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Affiliation(s)
- Chueh Lin Hsu
- Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland
| | - Piotr Iwanowski
- Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland
| | - Chueh Hsuan Hsu
- Department of Neurology, China Medical University, Taichung, Taiwan
| | - Wojciech Kozubski
- Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland
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11
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Olsen SH, Friborg J, Ellefsen B, Jakobsen KK, Aanæs K. Incidence and survival of head and neck cancer in the Faroe Islands. Int J Circumpolar Health 2021; 80:1894697. [PMID: 33719929 PMCID: PMC7971248 DOI: 10.1080/22423982.2021.1894697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background: The Faroese people constitute a geographically isolated population, and research on cancer in this population is sparse. Thus, this study aimed to calculate the age-standardised incidence rate (ASIR) and 5-year survival rates in head and neck cancers (HNC) in the Faroese population from 1985 to 2017. Materials and methods: All patients registered with HNC in the Faroese Cancer Registry (FCR) from 1985 to 2017 were included. The ASIR per 100,000 (World Standard Population) and 5-year survival rates were calculated. We also calculated the distribution of tobacco, alcohol consumption, cancer stages and various timelines. Results: 202 patients were included in the study (62% men). The ASIR for all HNC was 10.0/100,000 persons-years and was higher among men than women. Women’s survival rate was significantly higher than men’s (p = 0.026). The results imply that oropharyngeal cancer (OPC) had the best survival rate and was diagnosed at a significantly earlier stage. Conclusion: This retrospective nation-wide study showed that ASIRs and 5-year survival rates for Faroese HNC patients in general resembled the ones reported for Danish HNC patients. Timelines for Faroese HNC patients were shorter compared with Greenlandic HNC patients, but longer compared with the Danish fast track programme limits.
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Affiliation(s)
- Sunnvá Hanusardóttir Olsen
- Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Surgery, National Hospital of the Faroe Islands, Tórshavn, Faroe Islands.,Research Unit of the Medical Department, National Hospital of the Faroe Islands, Tórshavn, Faroe Islands
| | - Jeppe Friborg
- Department of Oncology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Bjarki Ellefsen
- Department of Surgery, National Hospital of the Faroe Islands, Tórshavn, Faroe Islands
| | - Kathrine Kronberg Jakobsen
- Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Kasper Aanæs
- Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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12
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Yap ZY, Strucinska K, Matsuzaki S, Lee S, Si Y, Humphries K, Tarnopolsky MA, Yoon WH. A biallelic pathogenic variant in the OGDH gene results in a neurological disorder with features of a mitochondrial disease. J Inherit Metab Dis 2021; 44:388-400. [PMID: 32383294 PMCID: PMC7647956 DOI: 10.1002/jimd.12248] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 12/27/2022]
Abstract
2-Oxoglutarate dehydrogenase (OGDH) is a rate-limiting enzyme in the mitochondrial TCA cycle, encoded by the OGDH gene. α-Ketoglutarate dehydrogenase (OGDH) deficiency was previously reported in association with developmental delay, hypotonia, and movement disorders and metabolic decompensation, with no genetic data provided. Using whole exome sequencing, we identified two individuals carrying a homozygous missense variant c.959A>G (p.N320S) in the OGDH gene. These individuals presented with global developmental delay, elevated lactate, ataxia and seizure. Fibroblast analysis and modeling of the mutation in Drosophila were used to evaluate pathogenicity of the variant. Skin fibroblasts from subject # 2 showed a decrease in both OGDH protein and enzyme activity. Transfection of human OGDH cDNA in HEK293 cells carrying p.N320S also produced significantly lower protein levels compared to those with wild-type cDNA. Loss of Drosophila Ogdh (dOgdh) caused early developmental lethality, rescued by expressing wild-type dOgdh (dOgdhWT ) or human OGDH (OGDHWT ) cDNA. In contrast, expression to the mutant OGDH (OGDHN320S ) or dOgdh carrying homologous mutations to human OGDH p.N320S variant (dOgdhN324S ) failed to rescue lethality of dOgdh null mutants. Knockdown of dOgdh in the nervous system resulted in locomotion defects which were rescued by dOgdhWT expression but not by dOgdhN324S expression. Collectively, the results indicate that c.959A>G variant in OGDH leads to an amino acid change (p.N320S) causing a severe loss of OGDH protein function. Our study establishes in the first time a genetic link between an OGDH gene mutation and OGDH deficiency.
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Affiliation(s)
- Zheng Yie Yap
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Klaudia Strucinska
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Satoshi Matsuzaki
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Sukyeong Lee
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas
| | | | - Kenneth Humphries
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | | | - Wan Hee Yoon
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
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13
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Chakrabarty S, Govindaraj P, Sankaran BP, Nagappa M, Kabekkodu SP, Jayaram P, Mallya S, Deepha S, Ponmalar JNJ, Arivinda HR, Meena AK, Jha RK, Sinha S, Gayathri N, Taly AB, Thangaraj K, Satyamoorthy K. Contribution of nuclear and mitochondrial gene mutations in mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. J Neurol 2021; 268:2192-2207. [PMID: 33484326 PMCID: PMC8179915 DOI: 10.1007/s00415-020-10390-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/27/2020] [Accepted: 12/28/2020] [Indexed: 11/30/2022]
Abstract
Background Mitochondrial disorders are clinically complex and have highly variable phenotypes among all inherited disorders. Mutations in mitochon
drial DNA (mtDNA) and nuclear genome or both have been reported in mitochondrial diseases suggesting common pathophysiological pathways. Considering the clinical heterogeneity of mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) phenotype including focal neurological deficits, it is important to look beyond mitochondrial gene mutation. Methods The clinical, histopathological, biochemical analysis for OXPHOS enzyme activity, and electron microscopic, and neuroimaging analysis was performed to diagnose 11 patients with MELAS syndrome with a multisystem presentation. In addition, whole exome sequencing (WES) and whole mitochondrial genome sequencing were performed to identify nuclear and mitochondrial mutations. Results Analysis of whole mtDNA sequence identified classical pathogenic mutation m.3243A > G in seven out of 11 patients. Exome sequencing identified pathogenic mutation in several nuclear genes associated with mitochondrial encephalopathy, sensorineural hearing loss, diabetes, epilepsy, seizure and cardiomyopathy (POLG, DGUOK, SUCLG2, TRNT1, LOXHD1, KCNQ1, KCNQ2, NEUROD1, MYH7) that may contribute to classical mitochondrial disease phenotype alone or in combination with m.3243A > G mutation. Conclusion Individuals with MELAS exhibit clinical phenotypes with varying degree of severity affecting multiple systems including auditory, visual, cardiovascular, endocrine, and nervous system. This is the first report to show that nuclear genetic factors influence the clinical outcomes/manifestations of MELAS subjects alone or in combination with m.3243A > G mutation. Electronic supplementary material The online version of this article (10.1007/s00415-020-10390-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sanjiban Chakrabarty
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| | - Periyasamy Govindaraj
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.,Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.,Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.,Institute of Bioinformatics, International Tech Park, Bangalore, India.,Manipal Academy of Higher Education, Manipal, India
| | - Bindu Parayil Sankaran
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.,Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.,Genetic Metabolic Disorders Service, Children's Hospital At Westmead, Sydney, NSW, Australia.,Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Madhu Nagappa
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.,Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Shama Prasada Kabekkodu
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| | - Pradyumna Jayaram
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| | - Sandeep Mallya
- Department of Bioinformatics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India
| | - Sekar Deepha
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.,Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - J N Jessiena Ponmalar
- Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Hanumanthapura R Arivinda
- Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | | | - Rajan Kumar Jha
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Sanjib Sinha
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Narayanappa Gayathri
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.,Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Arun B Taly
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.,Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Kumarasamy Thangaraj
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Kapaettu Satyamoorthy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, India.
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Alkhater RA, Ahonen S, Minassian BA. SUCLA2 Arg407Trp mutation can cause a nonprogressive movement disorder - deafness syndrome. Ann Clin Transl Neurol 2020; 8:252-258. [PMID: 33231368 PMCID: PMC7818133 DOI: 10.1002/acn3.51247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 10/04/2020] [Accepted: 10/13/2020] [Indexed: 11/25/2022] Open
Abstract
SUCLA2 is a component of mitochondrial succinate‐CoA ligase and nucleotide diphosphokinase activities. Its absence results in Krebs cycle failure, mitochondrial DNA depletion, and a childhood‐fatal encephalomyopathy. We describe a purely neurologic allelic form of the disease consisting of deafness, putamenal hyperintensity on MRI and a myoclonic‐dystonic movement disorder unchanging from childhood into, so far, the late fourth decade. We show that succinate supplementation circumvents the Krebs cycle block, but does not correct the neurologic disease. Our patients’ Arg407Trp mutation has been reported in children with (yet) no MRI abnormalities. It remains possible that early succinate supplementation could impact the disease.
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Affiliation(s)
- Reem A. Alkhater
- Program in Genetics and Genome BiologyThe Hospital for Sick ChildrenTorontoOntarioCanada
- Institute of Medical SciencesUniversity of TorontoTorontoOntarioCanada
- Johns’ Hopkins Aramco HealthcareDhahranSaudi Arabia
| | - Saija Ahonen
- Program in Genetics and Genome BiologyThe Hospital for Sick ChildrenTorontoOntarioCanada
| | - Berge A. Minassian
- Program in Genetics and Genome BiologyThe Hospital for Sick ChildrenTorontoOntarioCanada
- Institute of Medical SciencesUniversity of TorontoTorontoOntarioCanada
- Division of NeurologyDepartment of PediatricsUniversity of Texas SouthwesternDallasTexasUSA
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15
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SUCLA2 mutations cause global protein succinylation contributing to the pathomechanism of a hereditary mitochondrial disease. Nat Commun 2020; 11:5927. [PMID: 33230181 PMCID: PMC7684291 DOI: 10.1038/s41467-020-19743-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 10/26/2020] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial acyl-coenzyme A species are emerging as important sources of protein modification and damage. Succinyl-CoA ligase (SCL) deficiency causes a mitochondrial encephalomyopathy of unknown pathomechanism. Here, we show that succinyl-CoA accumulates in cells derived from patients with recessive mutations in the tricarboxylic acid cycle (TCA) gene succinyl-CoA ligase subunit-β (SUCLA2), causing global protein hyper-succinylation. Using mass spectrometry, we quantify nearly 1,000 protein succinylation sites on 366 proteins from patient-derived fibroblasts and myotubes. Interestingly, hyper-succinylated proteins are distributed across cellular compartments, and many are known targets of the (NAD+)-dependent desuccinylase SIRT5. To test the contribution of hyper-succinylation to disease progression, we develop a zebrafish model of the SCL deficiency and find that SIRT5 gain-of-function reduces global protein succinylation and improves survival. Thus, increased succinyl-CoA levels contribute to the pathology of SCL deficiency through post-translational modifications. The pathomechanism of succinyl-CoA ligase (SCL) deficiency, a hereditary mitochondrial disease, is not fully understood. Here, the authors show that increased succinyl-CoA levels contribute to SCL pathology by causing global protein hyper-succinylation.
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16
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Wang S, Liu Y, Liu J, Tian W, Zhang X, Cai H, Fang S, Yu B. Mitochondria-derived methylmalonic acid, a surrogate biomarker of mitochondrial dysfunction and oxidative stress, predicts all-cause and cardiovascular mortality in the general population. Redox Biol 2020; 37:101741. [PMID: 33035815 PMCID: PMC7554255 DOI: 10.1016/j.redox.2020.101741] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/20/2020] [Accepted: 09/24/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Inherited methylmalonic acidemia is characterized by mitochondrial dysfunction, oxidative stress, and damage of mitochondria-rich organs in children. It is unclear whether methylmalonic acid (MMA) is related to poor prognosis in adults. The study aims to investigate the associations of MMA with all-cause and cause-specific mortality in the general population. METHODS Overall, 23,437 adults from the US National Health and Nutrition Examination Survey (NHANES) were enrolled. NHANES 1999-2004 and 2011-2014 were separately used as primary and validation subsets (median follow-up 13.5 and 2.8 years, respectively). Circulating MMA was measured with gas chromatography/mass spectrophotometry. Hazard ratios (HR) were estimated using weighted Cox regression models. RESULTS During 163,632 person-years of follow-up in NHANES 1999-2004, 3019 deaths occurred. Compared with participants with MMA <120 nmol/L, those with MMA≥250 nmol/L had increased all-cause and cardiovascular mortality in the multivariable-adjusted model [HR(95%CI), 1.62 (1.43-1.84) and 1.66 (1.22-2.27), respectively]. The association was especially significant among participants with normal cobalamin. MMA remained an independent predictor of all-cause mortality occurring whether within 5-year, 5-10 years, or beyond 10-year of follow-up (each p for trend≤0.007). That association was repeatable in NHANES 2011-2014. Moreover, baseline MMA improved reclassification for 10-year mortality in patients with cardiovascular disease (net reclassification index 0.239, integrated discrimination improvement 0.022), overmatched established cardiovascular biomarkers C-reactive protein or homocysteine. CONCLUSIONS Circulating level of mitochondrial-derived MMA is strongly associated with elevated all-cause and cardiovascular mortality. Our results support MMA as a surrogate biomarker of mitochondrial dysfunction to predict poor prognosis in adults. The biological mechanisms under cardiovascular disease warrant further investigation.
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Affiliation(s)
- Shanjie Wang
- Department of Cardiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China; The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China
| | - Yige Liu
- Department of Cardiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China; The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China
| | - Jinxin Liu
- Department of Cardiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China; The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China
| | - Wei Tian
- Department of Epidemiology and Biostatistics, School of Public Health, Harbin Medical University, Harbin, China
| | - Xiaoyuan Zhang
- Department of Cardiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China; The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China
| | - Hengxuan Cai
- Department of Cardiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China; The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China
| | - Shaohong Fang
- Department of Cardiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China; The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China.
| | - Bo Yu
- Department of Cardiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China; The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China.
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17
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Petersen MS, Lophaven SN, Weihe P, Lynge E. High incidence of dementia in Faroese-born female residents in Denmark. ALZHEIMER'S & DEMENTIA (NEW YORK, N. Y.) 2020; 6:e12022. [PMID: 32346600 PMCID: PMC7185209 DOI: 10.1002/trc2.12022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/11/2020] [Indexed: 11/18/2022]
Abstract
INTRODUCTION To assess whether the incidence of dementia among immigrants in Denmark from the Faroe Islands is similar to that of the inhabitants of their new country. METHODS Data on Faroese-born immigrants in Denmark were retrieved from the Danish Central Population Register. Incident dementia cases were identified from the Danish National Patient Register. Standardized incidence ratios (SIRs) were used to compare the dementia incidence in immigrants with the general Danish population. RESULTS Female, first-generation Faroese immigrants had double the risk of dementia compared with Danes (SIR 2.1, 95% confidence interval [CI] 1.8-2.5); the excess risk prevailed even beyond 10 years in Denmark, and it affected all sub-types of dementia. In male immigrants, only a modest, statistically non-significant excess risk was seen (SIR 1.2, 95% CI 0.9-1.6). DISCUSSION The observation of an excess risk of dementia in women only but not in men of Faroese origin living in Denmark underscores the complexity of the etiology of dementia.
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Affiliation(s)
- Maria Skaalum Petersen
- Department of Occupational Medicine and Public HealthThe Faroese Hospital SystemTórshavnFaroe Islands
- Faculty of Health SciencesCentre of Health ScienceUniversity of the Faroe IslandsTórshavnFaroe Islands
| | | | - Pál Weihe
- Department of Occupational Medicine and Public HealthThe Faroese Hospital SystemTórshavnFaroe Islands
- Faculty of Health SciencesCentre of Health ScienceUniversity of the Faroe IslandsTórshavnFaroe Islands
| | - Elsebeth Lynge
- Nykøbing Falster HospitalUniversity of CopenhagenCopenhagenDenmark
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18
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Hong CM, Na JH, Park S, Lee YM. Clinical Characteristics of Early-Onset and Late-Onset Leigh Syndrome. Front Neurol 2020; 11:267. [PMID: 32351444 PMCID: PMC7174756 DOI: 10.3389/fneur.2020.00267] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 03/20/2020] [Indexed: 01/30/2023] Open
Abstract
Background: Leigh syndrome (LS) is the most common pediatric mitochondrial diseases caused by MRC defect. LS patients typically have onset age before 2 years old and have various clinical features. The purpose of this study was to evaluate the various characteristics between the group that were early onset and late onset patients. Methods: The medical records of this study used records between 2006 and 2017 (N = 110). Clinical characteristics, diagnostic evaluations, and neuro image studying of LS were reviewed in our study. We statistically analyzed data from patients diagnosed with LS at our hospital by using subgroup analysis was performed to divide patients according to the onset age. Results: Among the patients, 89 patients (80.9%) had the onset age before 2 years old, and 21 patents (19.1%) had onset age after 2 years old. In subgroup analysis first clinical presentation age, diagnosis age and several onset symptoms in the clinical characteristics were statistically significant. Early onset age group showed delayed development and late onset age group showed motor weakness and ataxia. However, Diagnostics evaluation and MRI findings showed no significant differences. The clinical status monitored during the last visit showed statistically significant differences in the clinical severity. In the early onset age group clinical status was more severe than late onset age group. Conclusions: Although the onset of Leigh syndrome is known to be under 2 years, there are many late onset cases were existed more than expected. Early onset LS patients have poor prognosis compare with late onset LS patients. Therefore, the specific phenotype according to the age of onset should be well-observed. Onset of LS is important in predicting clinical severity or prognosis, and it is necessary to provide individualized treatment or follow-up protocols for each patient.
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Affiliation(s)
- Chan-Mi Hong
- Departments of Pediatrics, Yonsei University College of Medicine, Seoul, South Korea
| | - Ji-Hoon Na
- Departments of Pediatrics, Yonsei University College of Medicine, Seoul, South Korea
| | - Soyoung Park
- Department of Pediatrics, Soon Chun Hyang University Hospital and College of Medicine, Soonchunhyang University, Bucheon-si, South Korea
| | - Young-Mock Lee
- Departments of Pediatrics, Yonsei University College of Medicine, Seoul, South Korea
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19
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Bohne VJB, Bohne Ø. Suggested pathology of systemic exertion intolerance disease: Impairment of the E 3 subunit or crossover of swinging arms of the E 2 subunit of the pyruvate dehydrogenase complex decreases regeneration of cofactor dihydrolipoic acid of the E 2 subunit. Med Hypotheses 2019; 130:109260. [PMID: 31383326 DOI: 10.1016/j.mehy.2019.109260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/22/2019] [Accepted: 06/07/2019] [Indexed: 10/26/2022]
Abstract
Systemic Exertion Intolerance Disease (SEID) or myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS) has an unknown aetiology, with no known treatment and a prevalence of approximately 22 million individuals (2%) in Western countries. Although strongly suspected, the role of lactate in pathology is unknown, nor has the nature of the two most central symptoms of the condition - post exertional malaise and fatigue. The proposed mechanism of action of pyruvate dehydrogenase complex (PDC) plays a central role in maintaining energy production with cofactors alpha-lipoic acid (LA) and its counterpart dihydrolipoic acid (DHLA), its regeneration suggested as the new rate limiting factor. Decreased DHLA regeneration due to impairment of the E3 subunit or crossover of the swinging arms of the E2 subunit of PDC have been suggested as a cause of ME/CFS/SEID resulting in instantaneous fluctuations in lactate levels and instantaneous offset of the DHLA/LA ratio and defining the condition as an LA deficiency with chronic instantaneous hyperlactataemia with explicit stratification of symptoms. While instantaneous hyperlactataemia has been suggested to account for the PEM, the fatigue was explained by the downregulated throughput of pyruvate and consequently lower production of ATP with the residual enzymatic efficacy of the E3 subunit or crossover of the E2 as a proposed explanation of the fatigue severity. Functional diagnostics and visualization of instantaneous elevations of lactate and DHLA has been suggested. Novel treatment strategies have been implicated to compensate for chronic PDC impairment and hyperlactataemia. This hypothesis potentially influences the current understanding and treatment methods for any type of hyperlactataemia, fatigue, ME/CFS/SEID, and conditions associated with PDC impairment.
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20
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Froese DS, Fowler B, Baumgartner MR. Vitamin B 12 , folate, and the methionine remethylation cycle-biochemistry, pathways, and regulation. J Inherit Metab Dis 2019; 42:673-685. [PMID: 30693532 DOI: 10.1002/jimd.12009] [Citation(s) in RCA: 176] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/27/2018] [Accepted: 10/19/2018] [Indexed: 12/16/2022]
Abstract
Vitamin B12 (cobalamin, Cbl) is a nutrient essential to human health. Due to its complex structure and dual cofactor forms, Cbl undergoes a complicated series of absorptive and processing steps before serving as cofactor for the enzymes methylmalonyl-CoA mutase and methionine synthase. Methylmalonyl-CoA mutase is required for the catabolism of certain (branched-chain) amino acids into an anaplerotic substrate in the mitochondrion, and dysfunction of the enzyme itself or in production of its cofactor adenosyl-Cbl result in an inability to successfully undergo protein catabolism with concomitant mitochondrial energy disruption. Methionine synthase catalyzes the methyl-Cbl dependent (re)methylation of homocysteine to methionine within the methionine cycle; a reaction required to produce this essential amino acid and generate S-adenosylmethionine, the most important cellular methyl-donor. Disruption of methionine synthase has wide-ranging implications for all methylation-dependent reactions, including epigenetic modification, but also for the intracellular folate pathway, since methionine synthase uses 5-methyltetrahydrofolate as a one-carbon donor. Folate-bound one-carbon units are also required for deoxythymidine monophosphate and de novo purine synthesis; therefore, the flow of single carbon units to each of these pathways must be regulated based on cellular needs. This review provides an overview on Cbl metabolism with a brief description of absorption and intracellular metabolic pathways. It also provides a description of folate-mediated one-carbon metabolism and its intersection with Cbl at the methionine cycle. Finally, a summary of recent advances in understanding of how both pathways are regulated is presented.
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Affiliation(s)
- D Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Brian Fowler
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
| | - Matthias R Baumgartner
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zurich, Switzerland
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21
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Hammer T, Lophaven SN, Nielsen KR, Petersen MS, Munkholm P, Weihe P, Burisch J, Lynge E. Dietary risk factors for inflammatory bowel diseases in a high-risk population: Results from the Faroese IBD study. United European Gastroenterol J 2019; 7:924-932. [PMID: 31428417 PMCID: PMC6683641 DOI: 10.1177/2050640619852244] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 04/28/2019] [Indexed: 12/30/2022] Open
Abstract
Background The Faroe Islands currently have the highest recorded inflammatory bowel disease (IBD) incidence in the world. Objective This study investigated environmental risk factors for IBD in the Faroese population. Methods Environmental exposure data including lifestyle risk factors and neurotoxicants collected for over 30 years were retrieved from the Children's Health and the Environment in the Faroes (CHEF) cohorts including mainly mother–child pairs, with exposure data collected from pregnant mothers. For lifestyle risk factors, the incidence of IBD and ulcerative colitis (UC) was calculated as the rate ratio (RR) with 95% confidence intervals (CI) in exposed versus non-exposed persons. For neurotoxicants RR was calculated for persons with high versus low exposure. Results Six cohorts included 5698 persons with complete follow-up data and at least one exposure, and 37 were diagnosed with IBD. For pilot whale/blubber, the RR was 1.02 (95% CI, 0.48–2.18); RR of 1.01 for fish (95% CI, 0.35–2.91); and of the pollutants studied, a statistical significantly increased risk was found for 1,1,1,-trichloro-2,2-bis-(p-chlorophenyl) ethane (p,p'-DDT); RR 3.04 (95% CI, 1.12–8.30). RRs were 1.96 (95% CI, 1.03–3.73) for smoking and 1.10 (95% CI, 0.55–2.19) for alcohol intake. Conclusion The high IBD incidence is unlikely to be caused by special dietary habits or by environmental pollutants.
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Affiliation(s)
- T Hammer
- Department of Occupational Medicine and Public Health, The Faroese Hospital System, Tórshavn, Faroe Islands.,Nykøbing Falster Hospital, University of Copenhagen, Copenhagen, Denmark
| | | | | | - M Skaalum Petersen
- Department of Occupational Medicine and Public Health, The Faroese Hospital System, Tórshavn, Faroe Islands.,Centre of Health Sciences, University of the Faroe Islands, Tórshavn, Faroe Islands
| | - P Munkholm
- Department of Gastroenterology, North Zealand Hospital, Frederikssund, Denmark
| | - P Weihe
- Department of Occupational Medicine and Public Health, The Faroese Hospital System, Tórshavn, Faroe Islands.,Centre of Health Sciences, University of the Faroe Islands, Tórshavn, Faroe Islands
| | - J Burisch
- Department of Gastroenterology, North Zealand Hospital, Frederikssund, Denmark
| | - E Lynge
- Nykøbing Falster Hospital, University of Copenhagen, Copenhagen, Denmark
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22
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Demirbas D, Harris DJ, Arn PH, Huang X, Waisbren SE, Anselm I, Lerner‐Ellis JP, Wong L, Levy HL, Berry GT. Phenotypic variability in deficiency of the α subunit of succinate-CoA ligase. JIMD Rep 2019; 46:63-69. [PMID: 31240156 PMCID: PMC6498818 DOI: 10.1002/jmd2.12018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 12/31/2018] [Indexed: 12/30/2022] Open
Abstract
Succinyl-CoA synthetase or succinate-CoA ligase deficiency can result from biallelic mutations in SUCLG1 gene that encodes for the alpha subunit of the succinyl-CoA synthetase. Mutations in this gene were initially associated with fatal infantile lactic acidosis. We describe an individual with a novel biallelic pathogenic mutation in SUCLG1 with a less severe phenotype dominated by behavioral problems. The mutation was identified to be c.512A>G corresponding to a p.Asn171Ser change in the protein. The liquid chromatography tandem mass spectrometry-based enzyme activity assay on cultured fibroblasts revealed a markedly reduced activity of succinyl-CoA synthetase enzyme when both ATP and GTP were substrates, affecting both ADP-forming and GDP-forming functions of the enzyme.
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Affiliation(s)
- Didem Demirbas
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - David J. Harris
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - Pamela H. Arn
- Department of PediatricsNemours Children's Health SystemJacksonvilleFlorida
| | - Xiaoping Huang
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - Susan E. Waisbren
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - Irina Anselm
- Department of NeurologyBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - Jordan P. Lerner‐Ellis
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | | | - Harvey L. Levy
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - Gerard T. Berry
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
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23
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Oyarzabal A, Marin-Valencia I. Synaptic energy metabolism and neuronal excitability, in sickness and health. J Inherit Metab Dis 2019; 42:220-236. [PMID: 30734319 DOI: 10.1002/jimd.12071] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 01/06/2019] [Accepted: 01/30/2019] [Indexed: 12/11/2022]
Abstract
Most of the energy produced in the brain is dedicated to supporting synaptic transmission. Glucose is the main fuel, providing energy and carbon skeletons to the cells that execute and support synaptic function: neurons and astrocytes, respectively. It is unclear, however, how glucose is provided to and used by these cells under different levels of synaptic activity. It is even more unclear how diseases that impair glucose uptake and oxidation in the brain alter metabolism in neurons and astrocytes, disrupt synaptic activity, and cause neurological dysfunction, of which seizures are one of the most common clinical manifestations. Poor mechanistic understanding of diseases involving synaptic energy metabolism has prevented the expansion of therapeutic options, which, in most cases, are limited to symptomatic treatments. To shed light on the intersections between metabolism, synaptic transmission, and neuronal excitability, we briefly review current knowledge of compartmentalized metabolism in neurons and astrocytes, the biochemical pathways that fuel synaptic transmission at resting and active states, and the mechanisms by which disorders of brain glucose metabolism disrupt neuronal excitability and synaptic function and cause neurological disease in the form of epilepsy.
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Affiliation(s)
- Alfonso Oyarzabal
- Synaptic Metabolism Laboratory, Department of Neurology, Hospital Sant Joan de Deu, Barcelona, Spain
| | - Isaac Marin-Valencia
- Laboratory of Developmental Neurobiology, The Rockefeller University, New York, New York
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24
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Cardoso TF, Amills M, Bertolini F, Rothschild M, Marras G, Boink G, Jordana J, Capote J, Carolan S, Hallsson JH, Kantanen J, Pons A, Lenstra JA. Patterns of homozygosity in insular and continental goat breeds. Genet Sel Evol 2018; 50:56. [PMID: 30449277 PMCID: PMC6241035 DOI: 10.1186/s12711-018-0425-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 10/15/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Genetic isolation of breeds may result in a significant loss of diversity and have consequences on health and performance. In this study, we examined the effect of geographic isolation on caprine genetic diversity patterns by genotyping 480 individuals from 25 European and African breeds with the Goat SNP50 BeadChip and comparing patterns of homozygosity of insular and nearby continental breeds. RESULTS Among the breeds analysed, number and total length of ROH varied considerably and depending on breeds, ROH could cover a substantial fraction of the genome (up to 1.6 Gb in Icelandic goats). When compared with their continental counterparts, goats from Iceland, Madagascar, La Palma and Ireland (Bilberry and Arran) displayed a significant increase in ROH coverage, ROH number and FROH values (P value < 0.05). Goats from Mediterranean islands represent a more complex case because certain populations displayed a significantly increased level of homozygosity (e.g. Girgentana) and others did not (e.g. Corse and Sarda). Correlations of number and total length of ROH for insular goat populations with the distance between islands and the nearest continental locations revealed an effect of extremely long distances on the patterns of homozygosity. CONCLUSIONS These results indicate that the effects of insularization on the patterns of homozygosity are variable. Goats raised in Madagascar, Iceland, Ireland (Bilberry and Arran) and La Palma, show high levels of homozygosity, whereas those bred in Mediterranean islands display patterns of homozygosity that are similar to those found in continental populations. These results indicate that the diversity of insular goat populations is modulated by multiple factors such as geographic distribution, population size, demographic history, trading and breed management.
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Affiliation(s)
- Taina F. Cardoso
- Department of Animal Genetics, Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona Spain
- CAPES Foundation, Ministry of Education of Brazil, Brasília, DF 70.040-020 Brazil
| | - Marcel Amills
- Department of Animal Genetics, Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona Spain
- Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Francesca Bertolini
- Department of Animal Science, Iowa State University, Ames, IA 50011-3150 USA
| | - Max Rothschild
- Department of Animal Science, Iowa State University, Ames, IA 50011-3150 USA
| | - Gabriele Marras
- Bioinformatics Core Facility, Fondazione Parco Tecnologico Padano, Loc. Cascina Codazza, 26900 Lodi, LO Italy
| | - Geert Boink
- Stichting Zeldzame Huisdierrassen, De Drieslag 30, 8251 JZ Dronten, The Netherlands
| | - Jordi Jordana
- Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Juan Capote
- Instituto Canario de Investigaciones Agrarias, 38108 La Laguna, Tenerife Spain
| | - Sean Carolan
- The Old Irish Goat Society, Mulranny, Co Mayo Ireland
| | - Jón H. Hallsson
- Faculty of Land and Animal Resources, Agricultural University of Iceland, Reykjavík, Iceland
| | - Juha Kantanen
- Department of Production Systems, Natural Resources Institute Finland, 31600 Jokioinen, Finland
| | - Agueda Pons
- Unitat de Races Autòctones, Servei de Millora Agrària i Pesquera (SEMILLA), 07198 Son Ferriol, Spain
| | - Johannes A. Lenstra
- Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - The AdaptMap Consortium
- Department of Animal Genetics, Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona Spain
- CAPES Foundation, Ministry of Education of Brazil, Brasília, DF 70.040-020 Brazil
- Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
- Department of Animal Science, Iowa State University, Ames, IA 50011-3150 USA
- Bioinformatics Core Facility, Fondazione Parco Tecnologico Padano, Loc. Cascina Codazza, 26900 Lodi, LO Italy
- Stichting Zeldzame Huisdierrassen, De Drieslag 30, 8251 JZ Dronten, The Netherlands
- Instituto Canario de Investigaciones Agrarias, 38108 La Laguna, Tenerife Spain
- The Old Irish Goat Society, Mulranny, Co Mayo Ireland
- Faculty of Land and Animal Resources, Agricultural University of Iceland, Reykjavík, Iceland
- Department of Production Systems, Natural Resources Institute Finland, 31600 Jokioinen, Finland
- Unitat de Races Autòctones, Servei de Millora Agrària i Pesquera (SEMILLA), 07198 Son Ferriol, Spain
- Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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25
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SURF1 mutations in Chinese patients with Leigh syndrome: Novel mutations, mutation spectrum, and the functional consequences. Gene 2018; 674:15-24. [DOI: 10.1016/j.gene.2018.06.058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/07/2018] [Accepted: 06/18/2018] [Indexed: 01/02/2023]
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26
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Grønborg S, Risom L, Ek J, Larsen KB, Scheie D, Petkov Y, Larsen VA, Dunø M, Joensen F, Østergaard E. A Faroese founder variant in TBCD causes early onset, progressive encephalopathy with a homogenous clinical course. Eur J Hum Genet 2018; 26:1512-1520. [PMID: 29921875 PMCID: PMC6138752 DOI: 10.1038/s41431-018-0204-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/22/2018] [Accepted: 06/05/2018] [Indexed: 11/08/2022] Open
Abstract
An intact and dynamic microtubule cytoskeleton is crucial for the development, differentiation, and maintenance of the mammalian cortex. Variants in a host of structural microtubulin-associated proteins have been identified to cause a wide spectrum of malformations of cortical development and alterations of microtubule dynamics have been recognized to cause or contribute to progressive neurodegenerative disorders. TBCD is one of the five tubulin-specific chaperones and is required for reversible assembly of the α-/β-tubulin heterodimer. Recently, variants in TBCD, and one other tubulin-specific chaperone, TBCE, have been identified in patients with distinct progressive encephalopathy with a seemingly broad clinical spectrum. Here, we report the clinical, neuroradiological, and neuropathological features in eight patients originating from the Faroe Islands, who presented with an early onset, progressive encephalopathy with features of primary neurodegeneration, and a homogenous clinical course. These patients were homozygous for a TBCD missense variant c.[3099C>G]; p.(Asn1033Lys), which we show has a high carrier frequency in the Faroese population (2.6%). The patients had similar age of onset as the previously reported patients (n = 24), but much shorter survival, which could be caused by either differences in supportive treatment, or alternatively, that shorter survival is intrinsic to the Faroese phenotype. We present a detailed description of the neuropathology and MR imaging characteristics of a subset of these patients, adding insight into the phenotype of TBCD-related encephalopathy. The finding of a Faroese founder variant will allow targeted genetic diagnostics in patients of Faroese descent as well as improved genetic counseling and testing of at-risk couples.
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Affiliation(s)
- Sabine Grønborg
- Department of Pediatrics, Center for Rare Diseases, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
| | - Lotte Risom
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Jakob Ek
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Karen Bonde Larsen
- Department of Pathology, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
- Department of Neuropathology and Ocular Pathology, John Radcliffe Hospital, Oxford University Hospital, Headley Way, Headington, Oxford, OX3 9DU, UK
| | - David Scheie
- Department of Pathology, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Yanko Petkov
- Department of Pediatrics, Esbjerg Hospital, Finsensgade 35, 6700, Esbjerg, Denmark
| | - Vibeke André Larsen
- Department of Radiology, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Morten Dunø
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Fróði Joensen
- Department of Pediatrics, National Hospital of the Faroe Islands, Tórshavn, Faroe Islands
| | - Elsebet Østergaard
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
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27
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Abstract
The heart failure accounts for the highest mortality rate all over the world. The development of preventive therapeutic approaches is still in their infancy. Owing to the extremely high energy demand of the heart, the bioenergetics pathways need to respond efficiently based on substrate availability. The metabolic regulation of such heart bioenergetics is mediated by various rate limiting enzymes involved in energy metabolism. Although all the pertinent mechanisms are not clearly understood, the progressive decline in the activity of metabolic enzymes leading to diminished ATP production is known to cause progression of the heart failure. Therefore, metabolic therapy that can maintain the appropriate activities of metabolic enzymes can be a promising approach for the prevention and treatment of the heart failure. The flavonoids that constitute various human dietary ingredients also effectively offer a variety of health benefits. The flavonoids target a variety of metabolic enzymes and facilitate effective management of the equilibrium between production and utilization of energy in the heart. This review discusses the broad impact of metabolic enzymes in the heart functions and explains how the dysregulated enzyme activity causes the heart failure. In addition, the prospects of targeting dysregulated metabolic enzymes by developing flavonoid-based metabolic approaches are discussed.
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28
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Sofou K, de Coo IFM, Ostergaard E, Isohanni P, Naess K, De Meirleir L, Tzoulis C, Uusimaa J, Lönnqvist T, Bindoff LA, Tulinius M, Darin N. Phenotype-genotype correlations in Leigh syndrome: new insights from a multicentre study of 96 patients. J Med Genet 2017; 55:21-27. [PMID: 29101127 DOI: 10.1136/jmedgenet-2017-104891] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/21/2017] [Accepted: 10/04/2017] [Indexed: 01/24/2023]
Abstract
BACKGROUND Leigh syndrome is a phenotypically and genetically heterogeneous mitochondrial disorder. While some genetic defects are associated with well-described phenotypes, phenotype-genotype correlations in Leigh syndrome are not fully explored. OBJECTIVE We aimed to identify phenotype-genotype correlations in Leigh syndrome in a large cohort of systematically evaluated patients. METHODS We studied 96 patients with genetically confirmed Leigh syndrome diagnosed and followed in eight European centres specialising in mitochondrial diseases. RESULTS We found that ataxia, ophthalmoplegia and cardiomyopathy were more prevalent among patients with mitochondrial DNA defects. Patients with mutations in MT-ND and NDUF genes with complex I deficiency shared common phenotypic features, such as early development of central nervous system disease, followed by high occurrence of cardiac and ocular manifestations. The cerebral cortex was affected in patients with NDUF mutations significantly more often than the rest of the cohort. Patients with the m.8993T>G mutation in MT-ATP6 gene had more severe clinical and radiological manifestations and poorer disease outcome compared with patients with the m.8993T>C mutation. CONCLUSION Our study provides new insights into phenotype-genotype correlations in Leigh syndrome and particularly in patients with complex I deficiency and with defects in the mitochondrial ATP synthase.
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Affiliation(s)
- Kalliopi Sofou
- Department of Pediatrics, The Queen Silvia Children's Hospital, University of Gothenburg, Gothenburg, Sweden
| | - Irenaeus F M de Coo
- Department of Neurology, The Erasmus University Medical Center, Rotterdam, Netherlands
| | - Elsebet Ostergaard
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Pirjo Isohanni
- Department of Paediatric Neurology, Children's Hospital, University of Helsinki, Helsinki University Hospital, Helsinki, Finland.,Research Programs Unit, Molecular Neurology, Biomedicum, University of Helsinki, Helsinki, Finland
| | - Karin Naess
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Linda De Meirleir
- Department of Paediatric Neurology, University Hospital Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Charalampos Tzoulis
- Department of Neurology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Johanna Uusimaa
- Department of Paediatrics, Institute of Clinical Medicine, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu University Hospital, Oulu, Finland
| | - Tuula Lönnqvist
- Department of Paediatric Neurology, Children's Hospital, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
| | - Laurence Albert Bindoff
- Department of Neurology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Már Tulinius
- Department of Pediatrics, The Queen Silvia Children's Hospital, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Darin
- Department of Pediatrics, The Queen Silvia Children's Hospital, University of Gothenburg, Gothenburg, Sweden
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29
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Abstract
Mitochondria are dynamic organelles present in virtually all human cells that are needed for a multitude of cellular functions, including energy production, control of cell apoptosis and numerous biochemical catabolic and synthetic pathways that are critical for cellular health. Primary mitochondrial disorders are a group of greater than 200 single gene defects arising from two genomes (nuclear and mitochondrial) leading to mitochondrial dysfunction, and are associated with extremely heterogeneous phenotypes. Neuromuscular features predominate, but often with multisystem involvement. Clinical suspicion of a mitochondrial disorder should prompt multipronged investigation with biochemical and molecular genetic studies. Recent wide-scale adoption of next-generation sequencing approaches has led to a rapid increase in the number of disease genes. The advances in unravelling the genetic landscape of mitochondrial diseases have not yet been matched by progress in developing effective therapies, and the mainstay of care remains supportive therapies in a multidisciplinary team setting.
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Affiliation(s)
- James E Davison
- Metabolic Unit,Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Shamima Rahman
- Metabolic Unit,Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.,Mitochondrial Research Group,UCL Great Ormond Street Institute of Child Health, London, UK
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30
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Couser NL, Marchuk DS, Smith LD, Arreola A, Kaiser-Rogers KA, Muenzer J, Pandya A, Gucsavas-Calikoglu M, Powell CM. Co-occurring Down syndrome and SUCLA2-related mitochondrial depletion syndrome. Am J Med Genet A 2017; 173:2720-2724. [PMID: 28749033 DOI: 10.1002/ajmg.a.38351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 06/09/2017] [Accepted: 06/14/2017] [Indexed: 01/23/2023]
Abstract
Mitochondrial DNA depletion syndrome 5 (MIM 612073) is a rare autosomal recessive disorder caused by homozygous or compound heterozygous pathogenic variants in the beta subunit of the succinate-CoA ligase gene located within the 13q14 band. We describe two siblings of Hispanic descent with SUCLA2-related mitochondrial depletion syndrome (encephalomyopathic form with methylmalonic aciduria); the older sibling is additionally affected with trisomy 21. SUCLA2 sequencing identified homozygous p.Arg284Cys pathogenic variants in both patients. This mutation has previously been identified in four individuals of Italian and Caucasian descent. The older sibling with concomitant disease has a more severe phenotype than what is typically described in patients with either SUCLA2-related mitochondrial depletion syndrome or Down syndrome alone. The younger sibling, who has a normal female chromosome complement, is significantly less affected compared to her brother. While the clinical and molecular findings have been reported in about 50 patients affected with a deficiency of succinate-CoA ligase caused by pathogenic variants in SUCLA2, this report describes the first known individual affected with both a mitochondrial depletion syndrome and trisomy 21.
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Affiliation(s)
- Natario L Couser
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Daniel S Marchuk
- University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Laurie D Smith
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Alexandra Arreola
- Department of Pathology & Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Kathleen A Kaiser-Rogers
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Pathology & Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Joseph Muenzer
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Arti Pandya
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Muge Gucsavas-Calikoglu
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Cynthia M Powell
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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31
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Viscomi C, Zeviani M. MtDNA-maintenance defects: syndromes and genes. J Inherit Metab Dis 2017; 40:587-599. [PMID: 28324239 PMCID: PMC5500664 DOI: 10.1007/s10545-017-0027-5] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 02/10/2017] [Accepted: 02/13/2017] [Indexed: 02/02/2023]
Abstract
A large group of mitochondrial disorders, ranging from early-onset pediatric encephalopathic syndromes to late-onset myopathy with chronic progressive external ophthalmoplegia (CPEOs), are inherited as Mendelian disorders characterized by disturbed mitochondrial DNA (mtDNA) maintenance. These errors of nuclear-mitochondrial intergenomic signaling may lead to mtDNA depletion, accumulation of mtDNA multiple deletions, or both, in critical tissues. The genes involved encode proteins belonging to at least three pathways: mtDNA replication and maintenance, nucleotide supply and balance, and mitochondrial dynamics and quality control. In most cases, allelic mutations in these genes may lead to profoundly different phenotypes associated with either mtDNA depletion or multiple deletions.
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Affiliation(s)
- Carlo Viscomi
- MRC-Mitochondrial Biology Unit, MRC MBU, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Massimo Zeviani
- MRC-Mitochondrial Biology Unit, MRC MBU, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.
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32
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Huang X, Bedoyan JK, Demirbas D, Harris DJ, Miron A, Edelheit S, Grahame G, DeBrosse SD, Wong LJ, Hoppel CL, Kerr DS, Anselm I, Berry GT. Succinyl-CoA synthetase (SUCLA2) deficiency in two siblings with impaired activity of other mitochondrial oxidative enzymes in skeletal muscle without mitochondrial DNA depletion. Mol Genet Metab 2017; 120:213-222. [PMID: 27913098 PMCID: PMC5346465 DOI: 10.1016/j.ymgme.2016.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 11/09/2016] [Accepted: 11/10/2016] [Indexed: 12/18/2022]
Abstract
Mutations in SUCLA2 result in succinyl-CoA ligase (ATP-forming) or succinyl-CoA synthetase (ADP-forming) (A-SCS) deficiency, a mitochondrial tricarboxylic acid cycle disorder. The phenotype associated with this gene defect is largely encephalomyopathy. We describe two siblings compound heterozygous for SUCLA2 mutations, c.985A>G (p.M329V) and c.920C>T (p.A307V), with parents confirmed as carriers of each mutation. We developed a new LC-MS/MS based enzyme assay to demonstrate the decreased SCS activity in the siblings with this unique genotype. Both siblings shared bilateral progressive hearing loss, encephalopathy, global developmental delay, generalized myopathy, and dystonia with choreoathetosis. Prior to diagnosis and because of lactic acidosis and low activity of muscle pyruvate dehydrogenase complex (PDC), sibling 1 (S1) was placed on dichloroacetate, while sibling 2 (S2) was on a ketogenic diet. S1 developed severe cyclic vomiting refractory to therapy, while S2 developed Leigh syndrome, severe GI dysmotility, intermittent anemia, hypogammaglobulinemia and eventually succumbed to his disorder. The mitochondrial DNA contents in skeletal muscle (SM) were normal in both siblings. Pyruvate dehydrogenase complex, ketoglutarate dehydrogenase complex, and several mitochondrial electron transport chain (ETC) activities were low or at the low end of the reference range in frozen SM from S1 and/or S2. In contrast, activities of PDC, other mitochondrial enzymes of pyruvate metabolism, ETC and, integrated oxidative phosphorylation, in skin fibroblasts were not significantly impaired. Although we show that propionyl-CoA inhibits PDC, it does not appear to account for decreased PDC activity in SM. A better understanding of the mechanisms of phenotypic variability and the etiology for tissue-specific secondary deficiencies of mitochondrial enzymes of oxidative metabolism, and independently mitochondrial DNA depletion (common in other cases of A-SCS deficiency), is needed given the implications for control of lactic acidosis and possible clinical management.
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Affiliation(s)
- Xiaoping Huang
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA
| | - Jirair K Bedoyan
- Center for Human Genetics, University Hospitals Cleveland Medical Center, Cleveland, OH, USA; Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA; Center for Inherited Disorders of Energy Metabolism (CIDEM), University Hospitals Cleveland Medical Center, Cleveland, OH, USA; Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Didem Demirbas
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA
| | - David J Harris
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Alexander Miron
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Simone Edelheit
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - George Grahame
- Center for Inherited Disorders of Energy Metabolism (CIDEM), University Hospitals Cleveland Medical Center, Cleveland, OH, USA
| | - Suzanne D DeBrosse
- Center for Human Genetics, University Hospitals Cleveland Medical Center, Cleveland, OH, USA; Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA; Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Charles L Hoppel
- Center for Inherited Disorders of Energy Metabolism (CIDEM), University Hospitals Cleveland Medical Center, Cleveland, OH, USA; Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA; Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Douglas S Kerr
- Center for Inherited Disorders of Energy Metabolism (CIDEM), University Hospitals Cleveland Medical Center, Cleveland, OH, USA; Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Irina Anselm
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Gerard T Berry
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
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Garone C, Gurgel-Giannetti J, Sanna-Cherchi S, Krishna S, Naini A, Quinzii CM, Hirano M. A Novel SUCLA2 Mutation Presenting as a Complex Childhood Movement Disorder. J Child Neurol 2017; 32:246-250. [PMID: 27651038 PMCID: PMC6815879 DOI: 10.1177/0883073816666221] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
SUCLA2 defects have been associated with mitochondrial DNA (mtDNA) depletion and the triad of hypotonia, dystonia/Leigh-like syndrome, and deafness. A 9-year-old Brazilian boy of consanguineous parents presented with psychomotor delay, deafness, myopathy, ataxia, and chorea. Despite the prominent movement disorder, brain magnetic resonance imaging (MRI) was normal while 1H-magnetic resonance spectroscopy (MRS) showed lactate peaks in the cerebral cortex and lateral ventricles. Decreased biochemical activities of mitochondrial respiratory chain enzymes containing mtDNA-encoded subunits and mtDNA depletion were observed in muscle and fibroblasts. A novel homozygous mutation in SUCLA2, the first one in the ligase coenzyme A (CoA) domain of the protein, was identified. Escalating doses of CoQ10 up to 2000 mg daily were associated with improvement of muscle weakness and stabilization of the disease course. The findings indicate the importance of screening for mitochondrial dysfunction in patients with complex movement disorders without brain MRI lesions and further investigation for potential secondary CoQ10 deficiency in patients with SUCLA2 mutations.
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Affiliation(s)
- Caterina Garone
- 1 Department of Neurology, Columbia University Medical Center, New York, NY, USA.,2 Universities of Turin and Bologna, Turin, Italy
| | - Juliana Gurgel-Giannetti
- 3 Department of Pediatrics, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Sindu Krishna
- 1 Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Ali Naini
- 5 Department of Pathology, Columbia University Medical Center, New York, NY, USA
| | - Catarina M Quinzii
- 1 Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Michio Hirano
- 1 Department of Neurology, Columbia University Medical Center, New York, NY, USA
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34
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Dai H, Zhang VW, El-Hattab AW, Ficicioglu C, Shinawi M, Lines M, Schulze A, McNutt M, Gotway G, Tian X, Chen S, Wang J, Craigen WJ, Wong LJ. FBXL4 defects are common in patients with congenital lactic acidemia and encephalomyopathic mitochondrial DNA depletion syndrome. Clin Genet 2017; 91:634-639. [PMID: 27743463 DOI: 10.1111/cge.12894] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/11/2016] [Accepted: 10/11/2016] [Indexed: 11/30/2022]
Abstract
Mutations in FBXL4 have recently been recognized to cause a mitochondrial disorder, with clinical features including early onset lactic acidosis, hypotonia, and developmental delay. FBXL4 sequence analysis was performed in 808 subjects suspected to have a mitochondrial disorder. In addition, 28 samples from patients with early onset of lactic acidosis, but without identifiable mutations in 192 genes known to cause mitochondrial diseases, were examined for FBXL4 mutations. Definitive diagnosis was made in 10 new subjects with a total of 7 novel deleterious variants; 5 null and 2 missense substitutions. All patients exhibited congenital lactic acidemia, most of them with severe encephalopathic presentation, and global developmental delay. Overall, FBXL4 defects account for at least 0.7% (6 out of 808) of subjects suspected to have a mitochondrial disorder, and as high as 14.3% (4 out of 28) in young children with congenital lactic acidosis and clinical features of mitochondrial disease. Including FBLX4 in the mitochondrial diseases panel should be particularly important for patients with congenital lactic acidosis.
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Affiliation(s)
- H Dai
- Baylor Genetics, Houston, TX, USA
| | - V W Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - A W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Pediatric Department, Tawam Hospital, Al-Ain, United Arab Emirates
| | - C Ficicioglu
- Division of Human Genetics and Metabolism, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - M Shinawi
- Division of Genetics and Genomics, Washington University School of Medicine, St. Louis, MO, USA
| | - M Lines
- Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - A Schulze
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - M McNutt
- Children's Medical Center, Dallas, TX, USA
| | - G Gotway
- Children's Medical Center, Dallas, TX, USA
| | - X Tian
- Baylor Genetics, Houston, TX, USA
| | - S Chen
- Baylor Genetics, Houston, TX, USA
| | - J Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - W J Craigen
- Baylor Genetics, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - L-J Wong
- Baylor Genetics, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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35
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Deficiency of succinyl-CoA synthetase α subunit delays development, impairs locomotor activity and reduces survival under starvation in Drosophila. Biochem Biophys Res Commun 2016; 483:566-571. [PMID: 28017724 DOI: 10.1016/j.bbrc.2016.12.105] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 12/16/2016] [Indexed: 11/23/2022]
Abstract
Succinyl-CoA synthetase/ligase (SCS) is a mitochondrial enzyme that catalyzes the reversible process from succinyl-CoA to succinate and free coenzyme A in TCA cycle. SCS deficiencies are implicated in mitochondrial hepatoencephalomyopathy in humans. To investigate the impact of SCS deficiencies in Drosophila, we generated a null mutation in Scs alpha subunit (Scsα) using the CRISPR/Cas9 system, and characterized their phenotype. We found that the Drosophila SCS deficiency, designated ScsαKO, contained a high level of succinyl-CoA, a substrate for the enzyme, and altered levels of various metabolites in TCA cycle and glycolysis, indicating that the energy metabolism was impaired. Unlike SCSα deficiencies in humans, there was no reduction in lifespan, indicating that Scsα is not critical for viability in Drosophila. However, they showed developmental delays, locomotor activity defects, and reduced survival under starvation. We also found that glycogen breakdown occurred during development, suggesting that the mutant flies were unable to produce sufficient energy to promote normal growth. These results suggested that SCSα is essential for proper energy metabolism in Drosophila. The ScsαKO flies should be useful as a model to understand the physiological role of SCSα as well as the pathophysiology of SCSα deficiency.
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36
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Truong DT, Shriberg LD, Smith SD, Chapman KL, Scheer-Cohen AR, DeMille MMC, Adams AK, Nato AQ, Wijsman EM, Eicher JD, Gruen JR. Multipoint genome-wide linkage scan for nonword repetition in a multigenerational family further supports chromosome 13q as a locus for verbal trait disorders. Hum Genet 2016; 135:1329-1341. [PMID: 27535846 PMCID: PMC5065602 DOI: 10.1007/s00439-016-1717-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/22/2016] [Indexed: 12/19/2022]
Abstract
Verbal trait disorders encompass a wide range of conditions and are marked by deficits in five domains that impair a person's ability to communicate: speech, language, reading, spelling, and writing. Nonword repetition is a robust endophenotype for verbal trait disorders that is sensitive to cognitive processes critical to verbal development, including auditory processing, phonological working memory, and motor planning and programming. In the present study, we present a six-generation extended pedigree with a history of verbal trait disorders. Using genome-wide multipoint variance component linkage analysis of nonword repetition, we identified a region spanning chromosome 13q14-q21 with LOD = 4.45 between 52 and 55 cM, spanning approximately 5.5 Mb on chromosome 13. This region overlaps with SLI3, a locus implicated in reading disability in families with a history of specific language impairment. Our study of a large multigenerational family with verbal trait disorders further implicates the SLI3 region in verbal trait disorders. Future studies will further refine the specific causal genetic factors in this locus on chromosome 13q that contribute to language traits.
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Affiliation(s)
- D T Truong
- Department of Pediatrics, Yale School of Medicine, New Haven, CT, 06510, USA
| | - L D Shriberg
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - S D Smith
- Department of Pediatrics, University of Nebraska at Omaha, Omaha, NE, 68182, USA
| | - K L Chapman
- Department of Communication Sciences and Disorders, University of Utah, Salt Lake City, UT, 84112, USA
| | - A R Scheer-Cohen
- Department of Speech-Language Pathology, California State University, San Marcos, CA, 92096, USA
| | - M M C DeMille
- Department of Pediatrics, Yale School of Medicine, New Haven, CT, 06510, USA
| | - A K Adams
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
| | - A Q Nato
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, 98195, USA
| | - E M Wijsman
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, 98195, USA
- Department of Biostatistics and Department of Genome Sciences, University of Washington, Seattle, WA, 98195, USA
| | - J D Eicher
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
| | - J R Gruen
- Department of Pediatrics, Yale School of Medicine, New Haven, CT, 06510, USA.
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA.
- Investigative Medicine Program, Yale School of Medicine, New Haven, CT, 06510, USA.
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37
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A short insertion mutation disrupts genesis of miR-16 and causes increased body weight in domesticated chicken. Sci Rep 2016; 6:36433. [PMID: 27808177 PMCID: PMC5093740 DOI: 10.1038/srep36433] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 10/17/2016] [Indexed: 11/26/2022] Open
Abstract
Body weight is one of the most important quantitative traits with high heritability in chicken. We previously mapped a quantitative trait locus (QTL) for body weight by genome-wide association study (GWAS) in an F2 chicken resource population. To identify the causal mutations linked to this QTL, expression profiles were determined on livers of high-weight and low-weight chicken lines by microarray. Combining the expression pattern with SNP effects by GWAS, miR-16 was identified as the most likely potential candidate with a 3.8-fold decrease in high-weight lines. Re-sequencing revealed that a 54-bp insertion mutation in the upstream region of miR-15a-16 displayed high allele frequencies in high-weight commercial broiler line. This mutation resulted in lower miR-16 expression by introducing three novel splicing sites instead of the missing 5′ terminal splicing of mature miR-16. Elevating miR-16 significantly inhibited DF-1 chicken embryo cell proliferation, consistent with a role in suppression of cellular growth. The 54-bp insertion was significantly associated with increased body weight, bone size and muscle mass. Also, the insertion mutation tended towards fixation in commercial broilers (Fst > 0.4). Our findings revealed a novel causative mutation for body weight regulation that aids our basic understanding of growth regulation in birds.
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38
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Grønborg S, Darin N, Miranda MJ, Damgaard B, Cayuela JA, Oldfors A, Kollberg G, Hansen TVO, Ravn K, Wibrand F, Østergaard E. Leukoencephalopathy due to Complex II Deficiency and Bi-Allelic SDHB Mutations: Further Cases and Implications for Genetic Counselling. JIMD Rep 2016; 33:69-77. [PMID: 27604842 DOI: 10.1007/8904_2016_582] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/08/2016] [Accepted: 08/11/2016] [Indexed: 01/08/2023] Open
Abstract
Isolated complex II deficiency is a rare cause of mitochondrial disease and bi-allelic mutations in SDHB have been identified in only a few patients with complex II deficiency and a progressive neurological phenotype with onset in infancy. On the other hand, heterozygous SDHB mutations are a well-known cause of familial paraganglioma/pheochromocytoma and renal cell cancer. Here, we describe two additional patients with respiratory chain deficiency due to bi-allelic SDHB mutations. The patients' clinical, neuroradiological, and biochemical phenotype is discussed according to current knowledge on complex II and SDHB deficiency and is well in line with previously described cases, thus confirming the specific neuroradiological presentation of complex II deficiency that recently has emerged. The patients' genotype revealed one novel SDHB mutation, and one SDHB mutation, which previously has been described in heterozygous form in patients with familial paraganglioma/pheochromocytoma and/or renal cell cancer. This is only the second example in the literature where one specific SDHx mutation is associated with both recessive mitochondrial disease in one patient and familial paraganglioma/pheochromocytoma in others. Due to uncertainties regarding penetrance of different heterozygous SDHB mutations, we argue that all heterozygous SDHB mutation carriers identified in relation to SDHB-related leukoencephalopathy should be referred to relevant surveillance programs for paraganglioma/pheochromocytoma and renal cell cancer. The diagnosis of complex II deficiency due to SDHB mutations therefore raises implications for genetic counselling that go beyond the recurrence risk in the family according to an autosomal recessive inheritance.
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Affiliation(s)
- Sabine Grønborg
- Center for Rare Diseases, Department of Clinical Genetics, Juliane Marie Center, University Hospital Copenhagen, Copenhagen, Denmark
| | - Niklas Darin
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, The Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Maria J Miranda
- Department of Pediatrics, Pediatric Neurology, Herlev University Hospital, Copenhagen University, Herlev, Denmark
| | - Bodil Damgaard
- Department of Diagnostic Imaging, Nordsjællands Hospital, Hillerød, Denmark
| | - Jorge Asin Cayuela
- Department of Clinical Chemistry, Sahlgrenska Academy, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Anders Oldfors
- Department of Pathology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Gittan Kollberg
- Department of Clinical Chemistry, Sahlgrenska Academy, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Thomas V O Hansen
- Center for Genomic Medicine, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Kirstine Ravn
- Department of Clinical Genetics 4062, Juliane Marie Center, University Hospital Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Flemming Wibrand
- Department of Clinical Genetics 4062, Juliane Marie Center, University Hospital Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Elsebet Østergaard
- Department of Clinical Genetics 4062, Juliane Marie Center, University Hospital Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark.
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39
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Two transgenic mouse models for β-subunit components of succinate-CoA ligase yielding pleiotropic metabolic alterations. Biochem J 2016; 473:3463-3485. [PMID: 27496549 PMCID: PMC5126846 DOI: 10.1042/bcj20160594] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/05/2016] [Indexed: 12/14/2022]
Abstract
Succinate-CoA ligase (SUCL) is a heterodimer enzyme composed of Suclg1 α-subunit and a substrate-specific Sucla2 or Suclg2 β-subunit yielding ATP or GTP, respectively. In humans, the deficiency of this enzyme leads to encephalomyopathy with or without methylmalonyl aciduria, in addition to resulting in mitochondrial DNA depletion. We generated mice lacking either one Sucla2 or Suclg2 allele. Sucla2 heterozygote mice exhibited tissue- and age-dependent decreases in Sucla2 expression associated with decreases in ATP-forming activity, but rebound increases in cardiac Suclg2 expression and GTP-forming activity. Bioenergetic parameters including substrate-level phosphorylation (SLP) were not different between wild-type and Sucla2 heterozygote mice unless a submaximal pharmacological inhibition of SUCL was concomitantly present. mtDNA contents were moderately decreased, but blood carnitine esters were significantly elevated. Suclg2 heterozygote mice exhibited decreases in Suclg2 expression but no rebound increases in Sucla2 expression or changes in bioenergetic parameters. Surprisingly, deletion of one Suclg2 allele in Sucla2 heterozygote mice still led to a rebound but protracted increase in Suclg2 expression, yielding double heterozygote mice with no alterations in GTP-forming activity or SLP, but more pronounced changes in mtDNA content and blood carnitine esters, and an increase in succinate dehydrogenase activity. We conclude that a partial reduction in Sucla2 elicits rebound increases in Suclg2 expression, which is sufficiently dominant to overcome even a concomitant deletion of one Suclg2 allele, pleiotropically affecting metabolic pathways associated with SUCL. These results as well as the availability of the transgenic mouse colonies will be of value in understanding SUCL deficiency.
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40
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Balasubramaniam S, Lewis B, Mock DM, Said HM, Tarailo-Graovac M, Mattman A, van Karnebeek CD, Thorburn DR, Rodenburg RJ, Christodoulou J. Leigh-Like Syndrome Due to Homoplasmic m.8993T>G Variant with Hypocitrullinemia and Unusual Biochemical Features Suggestive of Multiple Carboxylase Deficiency (MCD). JIMD Rep 2016; 33:99-107. [PMID: 27450367 DOI: 10.1007/8904_2016_559] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 03/09/2016] [Accepted: 03/16/2016] [Indexed: 01/15/2023] Open
Abstract
Leigh syndrome (LS), or subacute necrotizing encephalomyelopathy, is a genetically heterogeneous, relentlessly progressive, devastating neurodegenerative disorder that usually presents in infancy or early childhood. A diagnosis of Leigh-like syndrome may be considered in individuals who do not fulfil the stringent diagnostic criteria but have features resembling Leigh syndrome.We describe a unique presentation of Leigh-like syndrome in a 3-year-old boy with elevated 3-hydroxyisovalerylcarnitine (C5-OH) on newborn screening (NBS). Subsequent persistent plasma elevations of C5-OH and propionylcarnitine (C3) as well as fluctuating urinary markers were suggestive of multiple carboxylase deficiency (MCD). Normal enzymology and mutational analysis of genes encoding holocarboxylase synthetase (HLCS) and biotinidase (BTD) excluded MCD. Biotin uptake studies were normal excluding biotin transporter deficiency. His clinical features at 13 months of age comprised psychomotor delay, central hypotonia, myopathy, failure to thrive, hypocitrullinemia, recurrent episodes of decompensation with metabolic keto-lactic acidosis and an episode of hyperammonemia. Biotin treatment from 13 months of age was associated with increased patient activity, alertness, and attainment of new developmental milestones, despite lack of biochemical improvements. Whole exome sequencing (WES) analysis failed to identify any other variants which could likely contribute to the observed phenotype, apart from the homoplasmic (100%) m.8993T>G variant initially detected by mitochondrial DNA (mtDNA) sequencing.Hypocitrullinemia has been reported in patients with the m.8993T>G variant and other mitochondrial disorders. However, persistent plasma elevations of C3 and C5-OH have previously only been reported in one other patient with this homoplasmic mutation. We suggest considering the m.8993T>G variant early in the diagnostic evaluation of MCD-like biochemical disturbances, particularly when associated with hypocitrullinemia on NBS and subsequent confirmatory tests. An oral biotin trial is also warranted.
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Affiliation(s)
- Shanti Balasubramaniam
- Metabolic Unit, Department of Rheumatology and Metabolic Medicine, Princess Margaret Hospital, Perth, WA, Australia. .,School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia. .,Western Sydney Genetics Program, Children's Hospital at Westmead, Westmead, NSW, Australia.
| | - B Lewis
- PathWest Laboratories WA, Princess Margaret Hospital, Perth, WA, Australia
| | - D M Mock
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - H M Said
- Department of Medicine, University of California School of Medicine Irvine, Irvine, CA, USA
| | - M Tarailo-Graovac
- Centre for Molecular Medicine, Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - A Mattman
- Adult Metabolic Diseases Clinic, Division of Endocrinology and Metabolism, Vancouver General Hospital, UBC, Vancouver, BC, Canada
| | - C D van Karnebeek
- Centre for Molecular Medicine, Department of Pediatrics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - D R Thorburn
- Murdoch Childrens Research Institute and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - R J Rodenburg
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - J Christodoulou
- Murdoch Childrens Research Institute and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
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41
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Huang J, Fraser ME. Structural basis for the binding of succinate to succinyl-CoA synthetase. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2016; 72:912-21. [PMID: 27487822 DOI: 10.1107/s2059798316010044] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 06/20/2016] [Indexed: 01/19/2023]
Abstract
Succinyl-CoA synthetase catalyzes the only step in the citric acid cycle that provides substrate-level phosphorylation. Although the binding sites for the substrates CoA, phosphate, and the nucleotides ADP and ATP or GDP and GTP have been identified, the binding site for succinate has not. To determine this binding site, pig GTP-specific succinyl-CoA synthetase was crystallized in the presence of succinate, magnesium ions and CoA, and the structure of the complex was determined by X-ray crystallography to 2.2 Å resolution. Succinate binds in the carboxy-terminal domain of the β-subunit. The succinate-binding site is near both the active-site histidine residue that is phosphorylated in the reaction and the free thiol of CoA. The carboxy-terminal domain rearranges when succinate binds, burying this active site. However, succinate is not in position for transfer of the phosphoryl group from phosphohistidine. Here, it is proposed that when the active-site histidine residue has been phosphorylated by GTP, the phosphohistidine displaces phosphate and triggers the movement of the carboxylate of succinate into position to be phosphorylated. The structure shows why succinyl-CoA synthetase is specific for succinate and does not react appreciably with citrate nor with the other C4-dicarboxylic acids of the citric acid cycle, fumarate and oxaloacetate, but shows some activity with L-malate.
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Affiliation(s)
- Ji Huang
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Marie E Fraser
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
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42
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Güngör O, Özkaya AK, Güngör G, Karaer K, Dilber C, Aydin K. Novel mutation in SUCLA2 identified on sequencing analysis. Pediatr Int 2016; 58:659-61. [PMID: 26952923 DOI: 10.1111/ped.12921] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 12/01/2015] [Accepted: 01/12/2016] [Indexed: 11/26/2022]
Abstract
Succinate-CoA ligase, ADP-forming, beta subunit (SUCLA2)-related mitochondrial DNA depletion syndrome is caused by mutations affecting the ADP-using isoform of the beta subunit in succinyl-CoA synthase, which is involved in the Krebs cycle. The SUCLA2 protein is found mostly in heart, skeletal muscle, and brain tissues. SUCLA2 mutations result in a mitochondrial disorder that manifests as deafness, lesions in the basal ganglia, and encephalomyopathy accompanied by dystonia. Such mutations are generally associated with mildly increased plasma methylmalonic acid, increased plasma lactate, elevated plasma carnitine esters, and the presence of methylmalonic acid in urine. In this case report, we describe a new mutation in a patient with a succinyl-CoA synthase deficiency caused by an SUCLA2 defect.
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Affiliation(s)
- Olcay Güngör
- Department of Pediatric Neurology, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey
| | - Ahmet Kağan Özkaya
- Department of Pediatric Emergency, Faculty of Medicine, Cukurova University, Adana, Turkey
| | - Gülay Güngör
- Department of Radiology, Necip Fazıl City Hospital, Kahramanmaras, Turkey
| | - Kadri Karaer
- Department of Medical Genetics, Dr Ersin Arslan State Hospital, Gaziantep, Turkey
| | - Cengiz Dilber
- Department of Pediatric Neurology, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey
| | - Kürşad Aydin
- Department of Pediatric Neurology, Faculty of Medicine, Gazi University, Ankara, Turkey
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43
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Marras C, Lang A, van de Warrenburg BP, Sue CM, Tabrizi SJ, Bertram L, Mercimek-Mahmutoglu S, Ebrahimi-Fakhari D, Warner TT, Durr A, Assmann B, Lohmann K, Kostic V, Klein C. Nomenclature of genetic movement disorders: Recommendations of the international Parkinson and movement disorder society task force. Mov Disord 2016; 31:436-57. [PMID: 27079681 DOI: 10.1002/mds.26527] [Citation(s) in RCA: 173] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 10/21/2015] [Accepted: 11/22/2015] [Indexed: 12/11/2022] Open
Abstract
The system of assigning locus symbols to specify chromosomal regions that are associated with a familial disorder has a number of problems when used as a reference list of genetically determined disorders,including (I) erroneously assigned loci, (II) duplicated loci, (III) missing symbols or loci, (IV) unconfirmed loci and genes, (V) a combination of causative genes and risk factor genes in the same list, and (VI) discordance between phenotype and list assignment. In this article, we report on the recommendations of the International Parkinson and Movement Disorder Society Task Force for Nomenclature of Genetic Movement Disorders and present a system for naming genetically determined movement disorders that addresses these problems. We demonstrate how the system would be applied to currently known genetically determined parkinsonism, dystonia, dominantly inherited ataxia, spastic paraparesis, chorea, paroxysmal movement disorders, neurodegeneration with brain iron accumulation, and primary familial brain calcifications. This system provides a resource for clinicians and researchers that, unlike the previous system, can be considered an accurate and criterion-based list of confirmed genetically determined movement disorders at the time it was last updated.
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Affiliation(s)
- Connie Marras
- Toronto Western Hospital Morton, Gloria Shulman Movement Disorders Centre, and the Edmond J. Safra Program in Parkinson's Disease, University of Toronto, Toronto, Canada
| | - Anthony Lang
- Toronto Western Hospital Morton, Gloria Shulman Movement Disorders Centre, and the Edmond J. Safra Program in Parkinson's Disease, University of Toronto, Toronto, Canada
| | - Bart P van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Carolyn M Sue
- Department of Neurology, Royal North Shore Hospital and Kolling Institute of Medical Research, University of Sydney, St. Leonards, New South Wales, Australia
| | - Sarah J Tabrizi
- Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, UK
| | - Lars Bertram
- Lübeck Interdisciplinary Platform for Genome Analytics (LIGA), Institutes of Neurogenetics and Integrative and Experimental Genomics, University of Lübeck, Lübeck, Germany
- School of Public Health, Faculty of Medicine, Imperial College, London, UK
| | - Saadet Mercimek-Mahmutoglu
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Canada
| | - Darius Ebrahimi-Fakhari
- Division of Pediatric Neurology and Inborn Errors of Metabolism, Department of Pediatrics, Heidelberg University Hospital, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany
- Department of Neurology & F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Thomas T Warner
- Reta Lila Weston Institute of Neurological Studies, Department of Molecular Neurosciences, UCL Institute of Neurology, London, UK
| | - Alexandra Durr
- Sorbonne Université, UPMC, Inserm and Hôpital de la Salpêtrière, Département de Génétique et Cytogénétique, Paris, France
| | - Birgit Assmann
- Division of Pediatric Neurology, Department of Pediatrics I, Heidelberg University Hospital, Ruprecht-Karls-University Heidelberg
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Vladimir Kostic
- Institute of Neurology, School of Medicine University of Belgrade, Belgrade, Serbia
| | - Christine Klein
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
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44
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Carrozzo R, Verrigni D, Rasmussen M, de Coo R, Amartino H, Bianchi M, Buhas D, Mesli S, Naess K, Born AP, Woldseth B, Prontera P, Batbayli M, Ravn K, Joensen F, Cordelli DM, Santorelli FM, Tulinius M, Darin N, Duno M, Jouvencel P, Burlina A, Stangoni G, Bertini E, Redonnet-Vernhet I, Wibrand F, Dionisi-Vici C, Uusimaa J, Vieira P, Osorio AN, McFarland R, Taylor RW, Holme E, Ostergaard E. Succinate-CoA ligase deficiency due to mutations in SUCLA2 and SUCLG1: phenotype and genotype correlations in 71 patients. J Inherit Metab Dis 2016; 39:243-52. [PMID: 26475597 DOI: 10.1007/s10545-015-9894-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/04/2015] [Accepted: 09/08/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND The encephalomyopathic mtDNA depletion syndrome with methylmalonic aciduria is associated with deficiency of succinate-CoA ligase, caused by mutations in SUCLA2 or SUCLG1. We report here 25 new patients with succinate-CoA ligase deficiency, and review the clinical and molecular findings in these and 46 previously reported patients. PATIENTS AND RESULTS Of the 71 patients, 50 had SUCLA2 mutations and 21 had SUCLG1 mutations. In the newly-reported 20 SUCLA2 patients we found 16 different mutations, of which nine were novel: two large gene deletions, a 1 bp duplication, two 1 bp deletions, a 3 bp insertion, a nonsense mutation and two missense mutations. In the newly-reported SUCLG1 patients, five missense mutations were identified, of which two were novel. The median onset of symptoms was two months for patients with SUCLA2 mutations and at birth for SUCLG1 patients. Median survival was 20 years for SUCLA2 and 20 months for SUCLG1. Notable clinical differences between the two groups were hepatopathy, found in 38% of SUCLG1 cases but not in SUCLA2 cases, and hypertrophic cardiomyopathy which was not reported in SUCLA2 patients, but documented in 14% of cases with SUCLG1 mutations. Long survival, to age 20 years or older, was reported in 12% of SUCLA2 and in 10% of SUCLG1 patients. The most frequent abnormality on neuroimaging was basal ganglia involvement, found in 69% of SUCLA2 and 80% of SUCLG1 patients. Analysis of respiratory chain enzyme activities in muscle generally showed a combined deficiency of complexes I and IV, but normal histological and biochemical findings in muscle did not preclude a diagnosis of succinate-CoA ligase deficiency. In five patients, the urinary excretion of methylmalonic acid was only marginally elevated, whereas elevated plasma methylmalonic acid was consistently found. CONCLUSIONS To our knowledge, this is the largest study of patients with SUCLA2 and SUCLG1 deficiency. The most important findings were a significantly longer survival in patients with SUCLA2 mutations compared to SUCLG1 mutations and a trend towards longer survival in patients with missense mutations compared to loss-of-function mutations. Hypertrophic cardiomyopathy and liver involvement was exclusively found in patients with SUCLG1 mutations, whereas epilepsy was much more frequent in patients with SUCLA2 mutations compared to patients with SUCLG1 mutations. The mutation analysis revealed a number of novel mutations, including a homozygous deletion of the entire SUCLA2 gene, and we found evidence of two founder mutations in the Scandinavian population, in addition to the known SUCLA2 founder mutation in the Faroe Islands.
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Affiliation(s)
- Rosalba Carrozzo
- Unit of Muscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Daniela Verrigni
- Unit of Muscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Magnhild Rasmussen
- Department of Clinical Neurosciences for Children, Oslo University Hospital, Oslo, Norway
| | - Rene de Coo
- Department of Neurology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Hernan Amartino
- Servicio de Neurología Infantil, Hospital Universitario Austral, Buenos Aires, Argentina
| | - Marzia Bianchi
- Unit of Muscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Daniela Buhas
- Department of Medical Genetics, Montreal Children's Hospital, Montréal, Quebéc, Canada
| | - Samir Mesli
- Biochemistry, CHU de Bordeaux, Bordeaux, France
| | - Karin Naess
- Department of Laboratory Medicine and Centre for Inherited Metabolic Diseases, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Alfred Peter Born
- Department of Pediatrics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Berit Woldseth
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Paolo Prontera
- Centro di Riferimento Regionale di Genetica Medica, Azienda Ospedaliera di Perugia, CREO, Perugia, Italy
| | - Mustafa Batbayli
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Kirstine Ravn
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Fróði Joensen
- Department of Pediatrics, National Hospital of the Faroe Islands, Tórshavn, Faroe Islands
| | - Duccio M Cordelli
- U.O. Neuropsichiatria Infantile - Franzoni, Policlinico S. Orsola Malpighi, Bologna, Italy
| | | | - Mar Tulinius
- Department of Pediatrics, University of Gothenburg, The Queen Silvia's Children Hospital, Gothenburg, Sweden
| | - Niklas Darin
- Department of Pediatrics, University of Gothenburg, The Queen Silvia's Children Hospital, Gothenburg, Sweden
| | - Morten Duno
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Philippe Jouvencel
- Neonatal and Pediatric Intensive Care Unit, Children's Hospital, Bordeaux, France
| | - Alberto Burlina
- Division of Inherited Metabolic Diseases, Department of Pediatrics, University Hospital of Padua, Padua, Italy
| | - Gabriela Stangoni
- Centro di Riferimento Regionale di Genetica Medica, Azienda Ospedaliera di Perugia, CREO, Perugia, Italy
| | - Enrico Bertini
- Unit of Muscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | | | - Flemming Wibrand
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Carlo Dionisi-Vici
- Division of Metabolism, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Johanna Uusimaa
- Institute of Clinical Medicine/Department of Paediatrics, Finland and Medical Research Center, University of Oulu, Oulu University Hospital, Oulu, Finland
| | - Paivi Vieira
- Institute of Clinical Medicine/Department of Paediatrics, Finland and Medical Research Center, University of Oulu, Oulu University Hospital, Oulu, Finland
| | - Andrés Nascimento Osorio
- Unidad de patología neuromuscular, Servicio de Neurología, Hospital Sant Joan de Déu. Hospital Sant Joan de Déu and CIBERER, ISCIII, Barcelona, Spain
| | - Robert McFarland
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK
| | - Elisabeth Holme
- Department of Clinical Chemistry, Institute of Biomedicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Elsebet Ostergaard
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
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45
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Gerards M, Sallevelt SCEH, Smeets HJM. Leigh syndrome: Resolving the clinical and genetic heterogeneity paves the way for treatment options. Mol Genet Metab 2016; 117:300-12. [PMID: 26725255 DOI: 10.1016/j.ymgme.2015.12.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 12/31/2022]
Abstract
Leigh syndrome is a progressive neurodegenerative disorder, affecting 1 in 40,000 live births. Most patients present with symptoms between the ages of three and twelve months, but adult onset Leigh syndrome has also been described. The disease course is characterized by a rapid deterioration of cognitive and motor functions, in most cases resulting in death due to respiratory failure. Despite the high genetic heterogeneity of Leigh syndrome, patients present with identical, symmetrical lesions in the basal ganglia or brainstem on MRI, while additional clinical manifestations and age of onset varies from case to case. To date, mutations in over 60 genes, both nuclear and mitochondrial DNA encoded, have been shown to cause Leigh syndrome, still explaining only half of all cases. In most patients, these mutations directly or indirectly affect the activity of the mitochondrial respiratory chain or pyruvate dehydrogenase complex. Exome sequencing has accelerated the discovery of new genes and pathways involved in Leigh syndrome, providing novel insights into the pathophysiological mechanisms. This is particularly important as no general curative treatment is available for this devastating disorder, although several recent studies imply that early treatment might be beneficial for some patients depending on the gene or process affected. Timely, gene-based personalized treatment may become an important strategy in rare, genetically heterogeneous disorders like Leigh syndrome, stressing the importance of early genetic diagnosis and identification of new genes/pathways. In this review, we provide a comprehensive overview of the most important clinical manifestations and genes/pathways involved in Leigh syndrome, and discuss the current state of therapeutic interventions in patients.
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Affiliation(s)
- Mike Gerards
- Department of Clinical Genetics, Research School GROW, Maastricht University Medical Centre, Maastricht, The Netherlands; Maastricht Center for Systems Biology (MaCSBio), Maastricht University Medical Centre, Maastricht, The Netherlands.
| | - Suzanne C E H Sallevelt
- Department of Clinical Genetics, Research School GROW, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Hubert J M Smeets
- Department of Clinical Genetics, Research School GROW, Maastricht University Medical Centre, Maastricht, The Netherlands
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46
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Lake NJ, Compton AG, Rahman S, Thorburn DR. Leigh syndrome: One disorder, more than 75 monogenic causes. Ann Neurol 2015; 79:190-203. [PMID: 26506407 DOI: 10.1002/ana.24551] [Citation(s) in RCA: 301] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/16/2015] [Accepted: 10/18/2015] [Indexed: 12/19/2022]
Abstract
Leigh syndrome is the most common pediatric presentation of mitochondrial disease. This neurodegenerative disorder is genetically heterogeneous, and to date pathogenic mutations in >75 genes have been identified, encoded by 2 genomes (mitochondrial and nuclear). More than one-third of these disease genes have been characterized in the past 5 years alone, reflecting the significant advances made in understanding its etiological basis. We review the diverse biochemical and genetic etiology of Leigh syndrome and associated clinical, neuroradiological, and metabolic features that can provide clues for diagnosis. We discuss the emergence of genotype-phenotype correlations, insights gleaned into the molecular basis of disease, and available therapeutic options.
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Affiliation(s)
- Nicole J Lake
- Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Alison G Compton
- Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Shamima Rahman
- Mitochondrial Research Group, Genetics and Genomic Medicine, Institute of Child Health, University College London and Metabolic Unit, Great Ormond Street Hospital, London, United Kingdom
| | - David R Thorburn
- Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,Victorian Clinical Genetic Services, Royal Children's Hospital, Melbourne, Victoria, Australia
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47
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Maas RR, Marina AD, de Brouwer APM, Wevers RA, Rodenburg RJ, Wortmann SB. SUCLA2 Deficiency: A Deafness-Dystonia Syndrome with Distinctive Metabolic Findings (Report of a New Patient and Review of the Literature). JIMD Rep 2015; 27:27-32. [PMID: 26409464 DOI: 10.1007/8904_2015_464] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/26/2015] [Accepted: 05/20/2015] [Indexed: 12/24/2022] Open
Abstract
SUCLA2 encodes for a subunit of succinyl-coenzyme A synthase, the enzyme that reversibly synthesises succinyl-coenzyme A and ATP from succinate, coenzyme A and ADP in the Krebs cycle. Disruption of SUCLA2 function can lead to mitochondrial DNA depletion. Patients with a SUCLA2 mutation present with a rare but distinctive deafness-dystonia syndrome. Additionally, they exhibit elevated levels of the characteristic biochemical markers: methylmalonate, C4-dicarboxylic carnitine and lactate are increased in both plasma and urine. Thus far, eight different disease-causing SUCLA2 mutations, of which six missense mutations and two splice site mutations, have been described in the literature. Here, we present the first patient with an intragenic deletion in SUCLA2 and review the patients described in literature.
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Affiliation(s)
- Roeltje R Maas
- Amalia Children's Hospital, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Adela Della Marina
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, University of Essen, Essen, Germany
| | - Arjan P M de Brouwer
- Department of Human Genetics, Radboud University Nijmegen, Nijmegen, The Netherlands.,Department of Cognitive Neurosciences, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Ron A Wevers
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud UMC, Nijmegen, The Netherlands
| | - Richard J Rodenburg
- Amalia Children's Hospital, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Saskia B Wortmann
- Amalia Children's Hospital, Radboud University Nijmegen, Nijmegen, The Netherlands.
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48
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Exercise Intolerance and Myoglobinuria Associated with a Novel Maternally Inherited MT-ND1 Mutation. JIMD Rep 2015; 25:65-70. [PMID: 26108648 DOI: 10.1007/8904_2015_459] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 05/05/2015] [Accepted: 05/07/2015] [Indexed: 10/23/2022] Open
Abstract
The most common clinical phenotype caused by a mtDNA mutation in complex I of the mitochondrial respiratory chain is Leber hereditary optic neuropathy. We report a family with a novel maternally inherited homoplasmic mtDNA m.4087A>G mutation in the ND1 gene (MT-ND1) associated with isolated myopathy, recurrent episodes of myoglobinuria, and rhabdomyolysis. DNA from blood in seven family members and muscle from four family members were PCR amplified and sequenced directly and assessed for the m.4087A>G variation in MT-ND1. Mitochondrial enzyme activity in all muscle biopsies was measured. PCR and direct sequencing of the MT-ND1 genes from blood showed that all seven family members were homoplasmic for the m.4087A>G mutation (NC_012920.1:c.781A>G). The mutation predicts a threonine to alanine substitution at position 261 (p.T261A). The same mutation was found in muscle of all four family members available for muscle biopsy, and biochemical analyses revealed an isolated complex I defect in muscle of all family members (range 22-52% of normal). Muscle morphology showed severe myopathic changes with internal nuclei in multiple fibers of all family members. Monosymptomatic myopathy with recurrent myoglobinuria is a rare phenotype of mitochondrial myopathies. We report this phenotype in a family affected by a novel homoplasmic mutation in MT-ND1. It is the first time such a phenotype has been associated with complex I gene mutations and a homoplasmic mutation of mtDNA.
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49
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Mitochondrial DNA Depletion and Deletions in Paediatric Patients with Neuromuscular Diseases: Novel Phenotypes. JIMD Rep 2015; 23:91-100. [PMID: 25940035 PMCID: PMC4484910 DOI: 10.1007/8904_2015_438] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 03/02/2015] [Accepted: 03/31/2015] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE To study the clinical manifestations and occurrence of mtDNA depletion and deletions in paediatric patients with neuromuscular diseases and to identify novel clinical phenotypes associated with mtDNA depletion or deletions. METHODS Muscle DNA samples from patients presenting with undefined encephalomyopathies or myopathies were analysed for mtDNA content by quantitative real-time PCR and for deletions by long-range PCR. Direct sequencing of mtDNA maintenance genes and whole-exome sequencing were used to study the genetic aetiologies of the diseases. Clinical and laboratory findings were collected. RESULTS Muscle samples were obtained from 104 paediatric patients with neuromuscular diseases. mtDNA depletion was found in three patients with severe early-onset encephalomyopathy or myopathy. Two of these patients presented with novel types of mitochondrial DNA depletion syndromes associated with increased serum creatine kinase (CK) and multiorgan disease without mutations in any of the known mtDNA maintenance genes; one patient had pathologic endoplasmic reticulum (ER) membranes in muscle. The third patient with mtDNA depletion was diagnosed with merosine-deficient muscular dystrophy caused by a homozygous mutation in the LAMA2 gene. Two patients with an early-onset Kearns-Sayre/Pearson-like phenotype harboured a large-scale mtDNA deletion, minor multiple deletions and high mtDNA content. CONCLUSIONS Novel encephalomyopathic mtDNA depletion syndrome with structural alterations in muscle ER was identified. mtDNA depletion may also refer to secondary mitochondrial changes related to muscular dystrophy. We suggest that a large-scale mtDNA deletion, minor multiple deletions and high mtDNA content associated with Kearns-Sayre/Pearson syndromes may be secondary changes caused by mutations in an unknown nuclear gene.
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50
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Neonatal mitochondrial hepatoencephalopathy caused by novel GFM1 mutations. Mol Genet Metab Rep 2015; 3:5-10. [PMID: 26937387 PMCID: PMC4750589 DOI: 10.1016/j.ymgmr.2015.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/29/2015] [Accepted: 01/29/2015] [Indexed: 01/22/2023] Open
Abstract
Disorders caused by defects in the mitochondrial translation system are clinically and genetically heterogeneous. The elongation phase of mitochondrial protein synthesis requires, among many other components, three nuclear-encoded elongation factors: EFTu (TUFM; 602389), EFTs (TSFM; 604723), and EFG1 (GFM1; 606639). Mutations have been identified in the genes encoding all three elongation factors, and they result in combined respiratory chain deficiencies and severe phenotypes with an early fatal outcome. So far, only eleven patients have been reported with mutations in GFM1. Here we describe an additional three patients with novel GFM1 mutations. Our results confirm the tissue-specific effect of GFM1 mutations, since we found only slightly decreased respiratory chain enzyme activities in muscle and fibroblasts, but a severe deficiency in the liver. Hence, a thorough biochemical evaluation is important to guide genetic investigation in patients suspected for a mitochondrial disorder.
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