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Bettinger CM, Dulz S, Atiskova Y, Guerreiro H, Schön G, Guder P, Maier SL, Denecke J, Bley AE. Overview of Neuro-Ophthalmic Findings in Leukodystrophies. J Clin Med 2024; 13:5114. [PMID: 39274327 PMCID: PMC11396446 DOI: 10.3390/jcm13175114] [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: 07/09/2024] [Revised: 08/10/2024] [Accepted: 08/13/2024] [Indexed: 09/16/2024] Open
Abstract
Background: Leukodystrophies are a group of rare genetic diseases that primarily affect the white matter of the central nervous system. The broad spectrum of metabolic and pathological causes leads to manifestations at any age, most often in childhood and adolescence, and a variety of symptoms. Leukodystrophies are usually progressive, resulting in severe disabilities and premature death. Progressive visual impairment is a common symptom. Currently, no overview of the manifold neuro-ophthalmologic manifestations and visual impact of leukodystrophies exists. Methods: Data from 217 patients in the Hamburg leukodystrophy cohort were analyzed retrospectively for neuro-ophthalmologic manifestations, age of disease onset, and magnetic resonance imaging, visual evoked potential, and optical coherence tomography findings and were compared with data from the literature. Results: In total, 68% of the patients suffered from neuro-ophthalmologic symptoms, such as optic atrophy, visual neglect, strabismus, and nystagmus. Depending on the type of leukodystrophy, neuro-ophthalmologic symptoms occurred early or late during the course of the disease. Magnetic resonance imaging scans revealed pathologic alterations in the visual tract that were temporally correlated with symptoms. Conclusions: The first optical coherence tomography findings in Krabbe disease and metachromatic leukodystrophy allow retinal assessments. Comprehensive literature research supports the results of this first overview of neuro-ophthalmologic findings in leukodystrophies.
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Affiliation(s)
| | - Simon Dulz
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Yevgeniya Atiskova
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Helena Guerreiro
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Gerhard Schön
- Center of Experimental Medicine, Institute for Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Philipp Guder
- Children's Hospital, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Sarah Lena Maier
- Children's Hospital, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Jonas Denecke
- Children's Hospital, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Annette E Bley
- Children's Hospital, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
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2
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Xu H, Ma K, Gao Y, Song Q, Chen C, Xu X, Peng J, Sun Y. Clinical characteristics of a case of multiple mitochondrial dysfunction syndrome 3. Mol Genet Genomic Med 2024; 12:e2485. [PMID: 38923322 PMCID: PMC11199327 DOI: 10.1002/mgg3.2485] [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: 12/05/2023] [Revised: 05/23/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
OBJECTIVE To further comprehend the phenotype of multiple mitochondrial dysfunction syndrome type 3 (MMDS3:OMIM#615330) caused by IBA57 mutation. We present a case involving a patient who experienced acute neurological regression, and the literature was reviewed. METHODS Clinical data and laboratory test results were collected; early language and development progress were tested; and genetic testing was performed. Bioinformatics analysis was performed using Mutation Taster and PolyPhen-2, and the literature in databases such as PubMed and CNKI was searched using MMDS3 and IBA57 as keywords. RESULTS The child, aged 1 year and 2 months, had motor decline, unable to sit alone, limited right arm movement, hypotonia, hyperreflexia of both knees, and Babinski sign positivity on the right side, accompanied by nystagmus. Blood lactate levels were elevated at 2.50 mmol/L. Brain MR indicated slight swelling in the bilateral frontoparietal and occipital white matter areas and the corpus callosum, with extensive abnormal signals on T1 and T2 images, along with the semioval center and occipital lobes bilaterally. The multiple abnormal signals in the brain suggested metabolic leukoencephalopathy. Whole-exome sequencing analysis revealed that the child had two heterozygous mutations in the IBA57 gene, c.286T>C (p.Y96H) (likely pathogenic, LP) and c.992T>A (p.L331Q) (variant of uncertain significance, VUS). As of March 2023, a literature search showed that 56 cases of MMDS3 caused by IBA57 mutation had been reported worldwide, with 35 cases reported in China. Among the 35 IBA57 mutations listed in the HGMD database, there were 28 missense or nonsense mutations, 2 splicing mutations, 2 small deletions, and 3 small insertions. CONCLUSION MMDS3 predominantly manifests in infancy, with primary symptoms including feeding difficulties, neurological functional regression, muscle weakness, with severe cases potentially leading to mortality. Diagnosis is supported by elevated lactate levels, multisystem impairment (including auditory and visual systems), and distinctive MRI findings. Whole-exome sequencing is crucial for diagnosis. Currently, cocktail therapy offers symptomatic relief.
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Affiliation(s)
- Hai Xu
- School of Clinical MedicineShandong Second Medical UniversityWeifangShandongChina
| | - Kai Ma
- Department of PediatricsChildren's Hospital Affiliated to Shandong UniversityJinanShandongChina
| | - Yuye Gao
- Department of PediatricsShandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinanShandongChina
| | - Qijun Song
- Department of PediatricsShandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinanShandongChina
| | - Chaojin Chen
- School of Clinical MedicineShandong Second Medical UniversityWeifangShandongChina
| | - Xiao Xu
- Department of PediatricsShandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinanShandongChina
| | - Jiaxi Peng
- School of Clinical MedicineShandong Second Medical UniversityWeifangShandongChina
| | - Yan Sun
- Department of PediatricsShandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinanShandongChina
- Endocrine department of Shandong HospitalShandong Provincial Clinical Research Center for Children's Health and Disease OfficeJinanShandongChina
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3
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Chin H, Cho J, Kim WJ, Kim SY, Lim BC, Kim KJ, Chae JH. A Case of Multiple Mitochondrial Dysfunctions Syndrome 4 with Novel ISCA2 Variants, Mimicking Post-Infectious Encephalitis. Child Neurol Open 2023; 10:2329048X231210421. [PMID: 37915614 PMCID: PMC10617010 DOI: 10.1177/2329048x231210421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/08/2023] [Accepted: 10/11/2023] [Indexed: 11/03/2023] Open
Abstract
ISCA2 loss of function leads to leukodystrophy and developmental regression (multiple mitochondrial dysfunctions syndrome 4 (MMDS4)). We present a first Korean case of MMDS4 presenting with rapid developmental regression and leukodystrophy after febrile episode, mimicking post-infectious encephalitis. The patient had displayed normal development until 12 months of age. At 13 months of age, one month after experiencing a post-vaccination fever, she quickly progressed to being unable to sit unassisted nor speak any words. Analysis of the cerebrospinal fluid (CSF) revealed lympho-dominant pleocytosis. Amino acid analysis of both the serum and CSF demonstrated elevated glycine exclusively in the CSF. Diffuse leukodystrophy was noted in the brain magnetic resonance image. Whole exome sequencing revealed compound heterozygous ISCA2 variants of c.166T>G, p.C56G and c.422A>C, p.Q141P. No evidence of mitochondrial disease other than bilateral optic atrophy was noted. In cases of early onset rapid developmental regression with leukodystrophy, MMDS4 should be considered.
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Affiliation(s)
- Hyungjin Chin
- Department of Pediatrics, Seoul National University College of Medicine, Jongno-gu, Korea
| | - Jaeso Cho
- Department of Genomic Medicine, Seoul National University Hospital, Jongno-gu, Korea
| | - Woo Joong Kim
- Department of Pediatrics, Seoul National University College of Medicine, Jongno-gu, Korea
| | - Soo Yeon Kim
- Department of Genomic Medicine, Seoul National University Hospital, Jongno-gu, Korea
| | - Byung Chan Lim
- Department of Pediatrics, Seoul National University College of Medicine, Jongno-gu, Korea
| | - Ki Joong Kim
- Department of Pediatrics, Seoul National University College of Medicine, Jongno-gu, Korea
| | - Jong Hee Chae
- Department of Pediatrics, Seoul National University College of Medicine, Jongno-gu, Korea
- Department of Genomic Medicine, Seoul National University Hospital, Jongno-gu, Korea
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4
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Camponeschi F, Ciofi-Baffoni S, Calderone V, Banci L. Molecular Basis of Rare Diseases Associated to the Maturation of Mitochondrial [4Fe-4S]-Containing Proteins. Biomolecules 2022; 12:biom12071009. [PMID: 35883565 PMCID: PMC9313013 DOI: 10.3390/biom12071009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/15/2022] [Accepted: 07/19/2022] [Indexed: 02/04/2023] Open
Abstract
The importance of mitochondria in mammalian cells is widely known. Several biochemical reactions and pathways take place within mitochondria: among them, there are those involving the biogenesis of the iron–sulfur (Fe-S) clusters. The latter are evolutionarily conserved, ubiquitous inorganic cofactors, performing a variety of functions, such as electron transport, enzymatic catalysis, DNA maintenance, and gene expression regulation. The synthesis and distribution of Fe-S clusters are strictly controlled cellular processes that involve several mitochondrial proteins that specifically interact each other to form a complex machinery (Iron Sulfur Cluster assembly machinery, ISC machinery hereafter). This machinery ensures the correct assembly of both [2Fe-2S] and [4Fe-4S] clusters and their insertion in the mitochondrial target proteins. The present review provides a structural and molecular overview of the rare diseases associated with the genes encoding for the accessory proteins of the ISC machinery (i.e., GLRX5, ISCA1, ISCA2, IBA57, FDX2, BOLA3, IND1 and NFU1) involved in the assembly and insertion of [4Fe-4S] clusters in mitochondrial proteins. The disease-related missense mutations were mapped on the 3D structures of these accessory proteins or of their protein complexes, and the possible impact that these mutations have on their specific activity/function in the frame of the mitochondrial [4Fe-4S] protein biogenesis is described.
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Affiliation(s)
- Francesca Camponeschi
- Magnetic Resonance Center CERM, University of Florence, 50019 Sesto Fiorentino, Italy; (F.C.); (L.B.)
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), 50019 Sesto Fiorentino, Italy
| | - Simone Ciofi-Baffoni
- Magnetic Resonance Center CERM, University of Florence, 50019 Sesto Fiorentino, Italy; (F.C.); (L.B.)
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), 50019 Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
- Correspondence: (S.C.-B.); (V.C.); Tel.: +39-055-4574192 (S.C.-B.); +39-055-4574276 (V.C.)
| | - Vito Calderone
- Magnetic Resonance Center CERM, University of Florence, 50019 Sesto Fiorentino, Italy; (F.C.); (L.B.)
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), 50019 Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
- Correspondence: (S.C.-B.); (V.C.); Tel.: +39-055-4574192 (S.C.-B.); +39-055-4574276 (V.C.)
| | - Lucia Banci
- Magnetic Resonance Center CERM, University of Florence, 50019 Sesto Fiorentino, Italy; (F.C.); (L.B.)
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), 50019 Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
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5
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Whitehead MT, Lai LM, Blüml S. Clinical 1H MRS in childhood neurometabolic diseases — part 2: MRS signatures. Neuroradiology 2022; 64:1111-1126. [DOI: 10.1007/s00234-022-02918-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/10/2022] [Indexed: 12/23/2022]
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6
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Sumathipala D, Strømme P, Fattahi Z, Lüders T, Sheng Y, Kahrizi K, Einarsen IH, Sloan JL, Najmabadi H, van den Heuvel L, Wevers RA, Guerrero-Castillo S, Mørkrid L, Valayannopoulos V, Backe PH, Venditti CP, van Karnebeek CD, Nilsen H, Frengen E, Misceo D. ZBTB11 dysfunction: spectrum of brain abnormalities, biochemical signature and cellular consequences. Brain 2022; 145:2602-2616. [PMID: 35104841 PMCID: PMC9337812 DOI: 10.1093/brain/awac034] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 12/07/2021] [Accepted: 12/20/2021] [Indexed: 11/25/2022] Open
Abstract
Bi-allelic pathogenic variants in ZBTB11 have been associated with intellectual developmental disorder, autosomal recessive 69 (MRT69; OMIM 618383). We report five patients from three families with novel, bi-allelic variants in ZBTB11. We have expanded the clinical phenotype of MRT69, documenting varied severity of atrophy affecting different brain regions and described combined malonic and methylmalonic aciduria as a biochemical manifestation. As ZBTB11 encodes for a transcriptional regulator, we performeded chromatin immunoprecipitation-sequencing targeting ZBTB11 in fibroblasts from patients and controls. Chromatin immunoprecipitation-sequencing revealed binding of wild-type ZBTB11 to promoters in 238 genes, among which genes encoding proteins involved in mitochondrial functions and RNA processing are over-represented. Mutated ZBTB11 showed reduced binding to 61 of the targeted genes, indicating that the variants act as loss of function. Most of these genes are related to mitochondrial functions. Transcriptome analysis of the patient fibroblasts revealed dysregulation of mitochondrial functions. In addition, we uncovered that reduced binding of the mutated ZBTB11 to ACSF3 leads to decreased ACSF3 transcript level, explaining combined malonic and methylmalonic aciduria. Collectively, these results expand the clinical spectrum of ZBTB11-related neurological disease and give insight into the pathophysiology in which the dysfunctional ZBTB11 affect mitochondrial functions and RNA processing contributing to the neurological and biochemical phenotypes.
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Affiliation(s)
| | | | - Zohreh Fattahi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Torben Lüders
- Department of Clinical Molecular Biology, Section of Clinical Molecular Biology (EpiGen), University of Oslo and Akershus University Hospital, Lørenskog, Norway
| | - Ying Sheng
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Ingunn Holm Einarsen
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Jennifer L Sloan
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, NHGRI, NIH, Bethesda, MD, USA
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Lambert van den Heuvel
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ron A Wevers
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands,United for Metabolic Disease—UMD, The Netherlands
| | - Sergio Guerrero-Castillo
- University Children’s Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Lars Mørkrid
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | | | - Paul Hoff Backe
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway,Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | - Charles P Venditti
- Organic Acid Research Section, Medical Genomics and Metabolic Genetics Branch, NHGRI, NIH, Bethesda, MD, USA
| | - Clara D van Karnebeek
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands,United for Metabolic Disease—UMD, The Netherlands,Department of Pediatrics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Hilde Nilsen
- Department of Clinical Molecular Biology, Section of Clinical Molecular Biology (EpiGen), University of Oslo and Akershus University Hospital, Lørenskog, Norway
| | | | - Doriana Misceo
- Correspondence to: Doriana Misceo Department of Medical Genetics Oslo University Hospital and University of Oslo Postboks 4956 Nydalen, 0424 Oslo, Norway E-mail:
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7
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Dietz JV, Fox JL, Khalimonchuk O. Down the Iron Path: Mitochondrial Iron Homeostasis and Beyond. Cells 2021; 10:cells10092198. [PMID: 34571846 PMCID: PMC8468894 DOI: 10.3390/cells10092198] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/22/2021] [Accepted: 08/23/2021] [Indexed: 12/20/2022] Open
Abstract
Cellular iron homeostasis and mitochondrial iron homeostasis are interdependent. Mitochondria must import iron to form iron–sulfur clusters and heme, and to incorporate these cofactors along with iron ions into mitochondrial proteins that support essential functions, including cellular respiration. In turn, mitochondria supply the cell with heme and enable the biogenesis of cytosolic and nuclear proteins containing iron–sulfur clusters. Impairment in cellular or mitochondrial iron homeostasis is deleterious and can result in numerous human diseases. Due to its reactivity, iron is stored and trafficked through the body, intracellularly, and within mitochondria via carefully orchestrated processes. Here, we focus on describing the processes of and components involved in mitochondrial iron trafficking and storage, as well as mitochondrial iron–sulfur cluster biogenesis and heme biosynthesis. Recent findings and the most pressing topics for future research are highlighted.
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Affiliation(s)
- Jonathan V. Dietz
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA;
| | - Jennifer L. Fox
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424, USA;
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA;
- Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, USA
- Fred and Pamela Buffett Cancer Center, Omaha, NE 68198, USA
- Correspondence:
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8
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A Review of Multiple Mitochondrial Dysfunction Syndromes, Syndromes Associated with Defective Fe-S Protein Maturation. Biomedicines 2021; 9:biomedicines9080989. [PMID: 34440194 PMCID: PMC8393393 DOI: 10.3390/biomedicines9080989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 11/25/2022] Open
Abstract
Mitochondrial proteins carrying iron-sulfur (Fe-S) clusters are involved in essential cellular pathways such as oxidative phosphorylation, lipoic acid synthesis, and iron metabolism. NFU1, BOLA3, IBA57, ISCA2, and ISCA1 are involved in the last steps of the maturation of mitochondrial [4Fe-4S]-containing proteins. Since 2011, mutations in their genes leading to five multiple mitochondrial dysfunction syndromes (MMDS types 1 to 5) were reported. The aim of this systematic review is to describe all reported MMDS-patients. Their clinical, biological, and radiological data and associated genotype will be compared to each other. Despite certain specific clinical elements such as pulmonary hypertension or dilated cardiomyopathy in MMDS type 1 or 2, respectively, nearly all of the patients with MMDS presented with severe and early onset leukoencephalopathy. Diagnosis could be suggested by high lactate, pyruvate, and glycine levels in body fluids. Genetic analysis including large gene panels (Next Generation Sequencing) or whole exome sequencing is needed to confirm diagnosis.
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9
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Alfadhel M, Almuqbil M, Al Mutairi F, Umair M, Almannai M, Alghamdi M, Althiyab H, Albarakati R, Bashiri FA, Alshuaibi W, Ba-Armah D, Saleh MA, Al-Asmari A, Faqeih E, Altuwaijri W, Al-Rumayyan A, Balwi MA, Ababneh F, Alswaid AF, Eyaid WM, Almontashiri NAM, Alhashem A, Hundallah K, Bertoli-Avella A, Bauer P, Beetz C, Alrifai MT, Alfares A, Tabarki B. The Leukodystrophy Spectrum in Saudi Arabia: Epidemiological, Clinical, Radiological, and Genetic Data. Front Pediatr 2021; 9:633385. [PMID: 34055681 PMCID: PMC8155587 DOI: 10.3389/fped.2021.633385] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 03/22/2021] [Indexed: 12/14/2022] Open
Abstract
Background: Leukodystrophies (LDs) are inherited heterogeneous conditions that affect the central nervous system with or without peripheral nerve involvement. They are individually rare, but collectively, they are common. Thirty disorders were included by the Global Leukodystrophy Initiative Consortium (GLIA) as LDs. Methods: We conducted a retrospective chart review of a consecutive series of patients diagnosed with different types of LD from four large tertiary referral centers in Riyadh, Saudi Arabia. Only those 30 disorders defined by GLIA as LDs were included. Results: In total, 83 children from 61 families were identified and recruited for this study. The male-to-female ratio was 1.5:1, and a consanguinity rate of 58.5% was observed. An estimated prevalence of 1:48,780 or 2.05/100,000 was observed based on the clinical cohort, whereas a minimum of 1:32,857 or 3.04/100,000 was observed based on the local genetic database. The central region of the country exhibited the highest prevalence of LDs (48.5%). The most common LD was metachromatic leukodystrophy (MLD), and it accounted for 25.3%. The most common disorder based on carrier frequency was AGS. Novel variants were discovered in 51% of the cases, but 49% possessed previously reported variants. Missense variants were high in number and accounted for 73% of all cases. Compared with other disorders, MLD due to saposin b deficiency was more common than expected, Pelizaeus-Merzbacher-like disease was more prevalent than Pelizaeus-Merzbacher disease, and X-linked adrenoleukodystrophy was less common than expected. The mortality rate among our patients with LD was 24%. Conclusion: To the best of our knowledge, this is the largest cohort of patients with LD from Saudi Arabia. We present epidemiological, clinical, radiological, and genetic data. Furthermore, we report 18 variants that have not been reported previously. These findings are of great clinical and molecular utility for diagnosing and managing patients with LD.
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Affiliation(s)
- Majid Alfadhel
- Division of Medical Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia.,Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia.,College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Mohammed Almuqbil
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia.,Division of Neurology, Department of Pediatrics, King Abdullah Specialist Children's Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Fuad Al Mutairi
- Division of Medical Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia.,College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Muhammad Umair
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Mohammed Almannai
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Malak Alghamdi
- Medical Genetics Division, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Hamad Althiyab
- Division of Medical Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Rayyan Albarakati
- Division of Medical Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Fahad A Bashiri
- Division of Neurology, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Walaa Alshuaibi
- Medical Genetics Division, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Duaa Ba-Armah
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia.,Division of Neurology, Department of Pediatrics, King Abdullah Specialist Children's Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Mohammed A Saleh
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Ali Al-Asmari
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Eissa Faqeih
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Waleed Altuwaijri
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia.,Division of Neurology, Department of Pediatrics, King Abdullah Specialist Children's Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Ahmed Al-Rumayyan
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia.,Division of Neurology, Department of Pediatrics, King Abdullah Specialist Children's Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Mohammed Ali Balwi
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia.,Pathology and Laboratory Medicine, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Faroug Ababneh
- Division of Medical Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Abdulrahman Faiz Alswaid
- Division of Medical Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia.,College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Wafaa M Eyaid
- Division of Medical Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia.,College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Naif A M Almontashiri
- Center for Genetics and Inherited Diseases, Taibah University, Almadinah Almunwarah, Saudi Arabia.,Faculty of Applied Medical Sciences, Taibah University, Almadinah Almunwarah, Saudi Arabia
| | - Amal Alhashem
- Division of Genetics, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Khalid Hundallah
- Division of Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | | | | | | | - Muhammad Talal Alrifai
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia.,Division of Neurology, Department of Pediatrics, King Abdullah Specialist Children's Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNG-HA), Riyadh, Saudi Arabia
| | - Ahmed Alfares
- Pathology and Laboratory Medicine, King Abdulaziz Medical City, Riyadh, Saudi Arabia.,Department of Pediatrics, Almulyda, Saudi Arabia. King Abdullah International Medical Research Center (KAIMRC), Qassim University, Riyadh, Saudi Arabia
| | - Brahim Tabarki
- Division of Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
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10
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Abstract
Mitochondria are essential in most eukaryotes and are involved in numerous biological functions including ATP production, cofactor biosyntheses, apoptosis, lipid synthesis, and steroid metabolism. Work over the past two decades has uncovered the biogenesis of cellular iron-sulfur (Fe/S) proteins as the essential and minimal function of mitochondria. This process is catalyzed by the bacteria-derived iron-sulfur cluster assembly (ISC) machinery and has been dissected into three major steps: de novo synthesis of a [2Fe-2S] cluster on a scaffold protein; Hsp70 chaperone-mediated trafficking of the cluster and insertion into [2Fe-2S] target apoproteins; and catalytic conversion of the [2Fe-2S] into a [4Fe-4S] cluster and subsequent insertion into recipient apoproteins. ISC components of the first two steps are also required for biogenesis of numerous essential cytosolic and nuclear Fe/S proteins, explaining the essentiality of mitochondria. This review summarizes the molecular mechanisms underlying the ISC protein-mediated maturation of mitochondrial Fe/S proteins and the importance for human disease.
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Affiliation(s)
- Roland Lill
- Institut für Zytobiologie, Philipps-Universität Marburg, 35032 Marburg, Germany;
- SYNMIKRO Zentrum für synthetische Mikrobiologie, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Sven-A Freibert
- Institut für Zytobiologie, Philipps-Universität Marburg, 35032 Marburg, Germany;
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11
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Abstract
Mitochondrial disease presenting in childhood is characterized by clinical, biochemical and genetic complexity. Some children are affected by canonical syndromes, but the majority have nonclassical multisystemic disease presentations involving virtually any organ in the body. Each child has a unique constellation of clinical features and disease trajectory, leading to enormous challenges in diagnosis and management of these heterogeneous disorders. This review discusses the classical mitochondrial syndromes presenting most frequently in childhood and then presents an organ-based perspective including systems less frequently linked to mitochondrial disease, such as skin and hair abnormalities and immune dysfunction. An approach to diagnosis is then presented, encompassing clinical evaluation and biochemical, neuroimaging and genetic investigations, and emphasizing the problem of phenocopies. The impact of next-generation sequencing is discussed, together with the importance of functional validation of novel genetic variants never previously linked to mitochondrial disease. The review concludes with a brief discussion of currently available and emerging therapies. The field of mitochondrial medicine has made enormous strides in the last 30 years, with approaching 400 different genes across two genomes now linked to primary mitochondrial disease. However, many important questions remain unanswered, including the reasons for tissue specificity and variability of clinical presentation of individuals sharing identical gene defects, and a lack of disease-modifying therapies and biomarkers to monitor disease progression and/or response to treatment.
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Affiliation(s)
- S Rahman
- Mitochondrial Research Group, UCL Great Ormond Street Institute of Child Health, London, UK
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12
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Hartman TG, Yosovich K, Michaeli HG, Blumkin L, Ben-Sira L, Lev D, Lerman-Sagie T, Zerem A. Expanding the genotype-phenotype spectrum of ISCA2-related multiple mitochondrial dysfunction syndrome-cavitating leukoencephalopathy and prolonged survival. Neurogenetics 2020; 21:243-249. [PMID: 32424628 DOI: 10.1007/s10048-020-00611-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/01/2020] [Indexed: 12/19/2022]
Abstract
Iron-sulfur cluster assembly 2 (ISCA2)-related multiple mitochondrial dysfunction syndrome 4 (MMDS4) is a fatal autosomal recessive mitochondrial leukoencephalopathy. The disease typically manifests with rapid neurodevelopmental deterioration during the first months of life leading to a vegetative state and early death. MRI demonstrates a demyelinating leukodystrophy. We describe an eleven-year-old boy with a milder phenotype of ISCA2 related disorder manifesting as: normal early development, acute infantile neurologic deterioration leading to stable spastic quadriparesis, optic atrophy and mild cognitive impairment. The first MRI demonstrated a diffuse demyelinating leukodystrophy. A sequential MRI revealed white matter rarefaction with well-delineated cysts. The patient harbors two novel bi-allelic variants (p.Ala2Asp and p.Pro138Arg) in ISCA2 inherited from heterozygous carrier parents. This report expands the clinical spectrum of ISCA2-related disorders to include a milder phenotype with a longer life span and better psychomotor function and cavitating leukodystrophy on MRI. We discuss the possible genetic explanation for the different presentation.
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Affiliation(s)
- Tamar Gur Hartman
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel
- School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Keren Yosovich
- Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel
| | - Hila Gur Michaeli
- Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel
| | - Lubov Blumkin
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Liat Ben-Sira
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Radiology Unit, TASMC, Tel Aviv, Israel
| | - Dorit Lev
- Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tally Lerman-Sagie
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ayelet Zerem
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel.
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
- Pediatric Neurology Unit, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
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13
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Update Review about Metabolic Myopathies. Life (Basel) 2020; 10:life10040043. [PMID: 32316520 PMCID: PMC7235760 DOI: 10.3390/life10040043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/15/2020] [Accepted: 04/15/2020] [Indexed: 12/13/2022] Open
Abstract
The aim of this review is to summarize and discuss recent findings and new insights in the etiology and phenotype of metabolic myopathies. The review relies on a systematic literature review of recent publications. Metabolic myopathies are a heterogeneous group of disorders characterized by mostly inherited defects of enzymatic pathways involved in muscle cell metabolism. Metabolic myopathies present with either permanent (fixed) or episodic abnormalities, such as weakness, wasting, exercise-intolerance, myalgia, or an increase of muscle breakdown products (creatine-kinase, myoglobin) during exercise. Though limb and respiratory muscles are most frequently affected, facial, extra-ocular, and axial muscles may be occasionally also involved. Age at onset and prognosis vary considerably. There are multiple disease mechanisms and the pathophysiology is complex. Genes most recently related to metabolic myopathy include PGM1, GYG1, RBCK1, VMA21, MTO1, KARS, and ISCA2. The number of metabolic myopathies is steadily increasing. There is limited evidence from the literature that could guide diagnosis and treatment of metabolic myopathies. Treatment is limited to mainly non-invasive or invasive symptomatic measures. In conclusion, the field of metabolic myopathies is evolving with the more widespread availability and application of next generation sequencing technologies worldwide. This will broaden the knowledge about pathophysiology and putative therapeutic strategies for this group of neuromuscular disorders.
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14
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Lebigot E, Hully M, Amazit L, Gaignard P, Michel T, Rio M, Lombès M, Thérond P, Boutron A, Golinelli-Cohen MP. Expanding the phenotype of mitochondrial disease: Novel pathogenic variant in ISCA1 leading to instability of the iron-sulfur cluster in the protein. Mitochondrion 2020; 52:75-82. [PMID: 32092383 DOI: 10.1016/j.mito.2020.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/31/2020] [Accepted: 02/19/2020] [Indexed: 11/20/2022]
Abstract
We report a patient carrying a novel pathogenic variant p.(Tyr101Cys) in ISCA1 leading to MMDS type 5. He initially presented a psychomotor regression with loss of gait and language skills and a tetrapyramidal spastic syndrome. Biochemical analysis of patient fibroblasts revealed impaired lipoic acid synthesis and decreased activities of complex I and II of respiratory chain. While ISCA1 is involved in the mitochondrial machinery for iron-sulfur cluster biogenesis, these dysfunctions are secondary to impaired maturation of mitochondrial proteins containing the [4Fe-4S] clusters. Expression and purification of the human ISCA1 showed a decreased stability of the [2Fe-2S] cluster in the mutated protein.
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Affiliation(s)
- E Lebigot
- Biochemistry Department, Hôpital Bicêtre, APHP Université Paris-Saclay, Le Kremlin Bicêtre F-94275, France; Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France.
| | - M Hully
- Pediatric Neurology Department, Hôpital Necker Enfants Malades, Institut Imagine, APHP Centre - Université de Paris, Paris F-75015, France
| | - L Amazit
- Institut National de la Santé et de la Recherche Médicale Unité 1185, Unité Mixte de Recherche Faculté de Médecine Paris-Sud, Université Paris-Sud, Université Paris Saclay, Le Kremlin Bicêtre F-94276, France; Unité mixte de Service 32, Institut Biomédical de Bicêtre, Le Kremlin-Bicêtre F-94276, France
| | - P Gaignard
- Biochemistry Department, Hôpital Bicêtre, APHP Université Paris-Saclay, Le Kremlin Bicêtre F-94275, France
| | - T Michel
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
| | - M Rio
- Genetic Department, Hôpital Necker Enfants Malades, Institut Imagine, APHP Centre - Université de Paris, Paris F-75015, France
| | - M Lombès
- Institut National de la Santé et de la Recherche Médicale Unité 1185, Unité Mixte de Recherche Faculté de Médecine Paris-Sud, Université Paris-Sud, Université Paris Saclay, Le Kremlin Bicêtre F-94276, France
| | - P Thérond
- Biochemistry Department, Hôpital Bicêtre, APHP Université Paris-Saclay, Le Kremlin Bicêtre F-94275, France
| | - A Boutron
- Biochemistry Department, Hôpital Bicêtre, APHP Université Paris-Saclay, Le Kremlin Bicêtre F-94275, France
| | - M P Golinelli-Cohen
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, 91198 Gif-sur-Yvette, France
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15
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Eidi M, Garshasbi M. A novel ISCA2 variant responsible for an early-onset neurodegenerative mitochondrial disorder: a case report of multiple mitochondrial dysfunctions syndrome 4. BMC Neurol 2019; 19:153. [PMID: 31279336 PMCID: PMC6612116 DOI: 10.1186/s12883-019-1387-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 07/01/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Multiple Mitochondrial Dysfunctions Syndrome 4 (MMDS4) is manifested as a result of ISCA2 mutations. ISCA2 is a vital component of 4Fe-4S clusters assembly machine. Therefore, in MMDS4 patients, deficient mitochondrial respiratory chain complexes I and II, Aconitase and Succinate dehydrogenase of Kerbs cycle and Lipoic Acid Synthetase in the biosynthesis of lipoic acid are expected. CASE PRESENTATIONS A 7 months boy in an Iranian consanguineous family with progressive neurodegenerative problems was referred to us. Primarily, general laboratory tests, Abdomen ultrasonography and brain magnetic resonance imaging were performed. In order to find out the genetic problem in this case Whole Exome Sequencing (WES) following by Sanger sequencing was carried out. A novel variant (c.355G > A, p.Ala119Thr) in ISCA2 gene was identified by WES in the proband. Confirmation and segregation in the family for this variant was performed by Sanger sequencing. In-Silico prediction of the ISCA2 secondary structure showed that a helix motif in the Fe-S biosynthesis domain of ISCA2 protein will be eliminated as a result of this variant. CONCLUSIONS We reported the first patient with ISCA2 variant in Iranian population and the third one in the world reported for ISCA2 gene, so far associated with early-onset mitochondrial neurodegeneration. However further functional studies on this variant or finding it in other patients with similar clinical problems are needed to confirm the pathogenicity of this variant.
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Affiliation(s)
- Milad Eidi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
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16
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Alfadhel M. Multiple Mitochondrial Dysfunctions Syndrome 4 Due to ISCA2 Gene Defects: A Review. Child Neurol Open 2019; 6:2329048X19847377. [PMID: 31106229 PMCID: PMC6506909 DOI: 10.1177/2329048x19847377] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 02/15/2019] [Accepted: 04/04/2019] [Indexed: 12/18/2022] Open
Abstract
Multiple mitochondrial dysfunctions syndrome 4, caused by ISCA2 gene
defects (OMIM #616370), was first described by Al-Hassnan et al in 2015. To date, 20 cases
have been reported: 13 females and 7 males from 18 different families. All cases are from
Saudi Arabia except those from one Italian family. Typically, the patients have normal
antenatal and birth history and attain normal development initially. Rapid deterioration
occurs between 2 and 7 months of age, with the triad of neurodevelopmental regression,
optic atrophy with nystagmus, and diffuse white matter disease. Magnetic resonance imaging
findings include 75% of patients have cerebellar white matter abnormalities, and the
spinal cord was affected in 55%. Magnetic resonance spectroscopy showed elevated glycine
peaks in 2 (10%) cases and elevated lactate peaks in 5 (25%) cases. Biochemical
abnormalities include high cerebrospinal fluid glycine and lactate and high plasma glycine
and lactate, but these findings were not consistent. Diagnosis is based on the detection
of biallelic mutations in the ISCA2 gene. To date, no curative treatment
has been discovered, and disease management is exclusively supportive. In this report, the
authors review the published cases of ISCA2 gene defects and
retrospectively characterize disease phenotypes, the affected biochemical pathways,
neuroradiological abnormalities, diagnosis, genetics, and treatment.
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Affiliation(s)
- Majid Alfadhel
- Division of Genetics, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
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17
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McCormick EM, Zolkipli-Cunningham Z, Falk MJ. Mitochondrial disease genetics update: recent insights into the molecular diagnosis and expanding phenotype of primary mitochondrial disease. Curr Opin Pediatr 2018; 30:714-724. [PMID: 30199403 PMCID: PMC6467265 DOI: 10.1097/mop.0000000000000686] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW Primary mitochondrial disease (PMD) is a genetically and phenotypically diverse group of inherited energy deficiency disorders caused by impaired mitochondrial oxidative phosphorylation (OXPHOS) capacity. Mutations in more than 350 genes in both mitochondrial and nuclear genomes are now recognized to cause primary mitochondrial disease following every inheritance pattern. Next-generation sequencing technologies have dramatically accelerated mitochondrial disease gene discovery and diagnostic yield. Here, we provide an up-to-date review of recently identified, novel mitochondrial disease genes and/or pathogenic variants that directly impair mitochondrial structure, dynamics, and/or function. RECENT FINDINGS A review of PubMed publications was performed from the past 12 months that identified 16 new PMD genes and/or pathogenic variants, and recognition of expanded phenotypes for a wide variety of mitochondrial disease genes. SUMMARY Broad-based exome sequencing has become the standard first-line diagnostic approach for PMD. This has facilitated more rapid and accurate disease identification, and greatly expanded understanding of the wide spectrum of potential clinical phenotypes. A comprehensive dual-genome sequencing approach to PMD diagnosis continues to improve diagnostic yield, advance understanding of mitochondrial physiology, and provide strong potential to develop precision therapeutics targeted to diverse aspects of mitochondrial disease pathophysiology.
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Affiliation(s)
- Elizabeth M. McCormick
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, The Children’s Hospital of Philadelphia, PA 19104
| | - Zarazuela Zolkipli-Cunningham
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, The Children’s Hospital of Philadelphia, PA 19104
| | - Marni J. Falk
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, The Children’s Hospital of Philadelphia, PA 19104
- Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
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18
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Finsterer J, Zarrouk-Mahjoub S. ISCA2 mutations manifest differentially from DARS2 mutations. Metab Brain Dis 2018; 33:1389-1390. [PMID: 29789987 DOI: 10.1007/s11011-018-0253-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 05/17/2018] [Indexed: 10/16/2022]
Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Postfach, 20 1180, Vienna, Austria.
| | - Sinda Zarrouk-Mahjoub
- Pasteur Institute of Tunis, University of Tunis El Manar and Genomics Platform, Tunis, Tunisia
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19
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Clinical and genetic aspects of defects in the mitochondrial iron-sulfur cluster synthesis pathway. J Biol Inorg Chem 2018; 23:495-506. [PMID: 29623423 PMCID: PMC6006192 DOI: 10.1007/s00775-018-1550-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 02/26/2018] [Indexed: 12/12/2022]
Abstract
Iron-sulfur clusters are evolutionarily conserved biological structures which play an important role as cofactor for multiple enzymes in eukaryotic cells. The biosynthesis pathways of the iron-sulfur clusters are located in the mitochondria and in the cytosol. The mitochondrial iron-sulfur cluster biosynthesis pathway (ISC) can be divided into at least twenty enzymatic steps. Since the description of frataxin deficiency as the cause of Friedreich's ataxia, multiple other deficiencies in ISC biosynthesis pathway have been reported. In this paper, an overview is given of the clinical, biochemical and genetic aspects reported in humans affected by a defect in iron-sulfur cluster biosynthesis.
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