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Zhang X, Zhang G, Cao L, Zhou W, Tan C, Ma S, Yang J. Two novel SUCLA2 variants cause mitochondrial DNA depletion syndrome, type 5 in two siblings. Front Neurol 2024; 15:1394150. [PMID: 39070054 PMCID: PMC11273780 DOI: 10.3389/fneur.2024.1394150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 07/03/2024] [Indexed: 07/30/2024] Open
Abstract
Mitochondrial DNA depletion syndrome (MDS), characterized by succinate-CoA ligase deficiency and loss of mitochondrial DNA (mtDNA), is caused by specific variants in nuclear genes responsible for mtDNA maintenance. SUCLA2-related mitochondrial DNA depletion syndrome, type 5 (MTDPS-5), presents as a rare, severe early progressive encephalomyopathy. This report investigates a new family exhibiting clinical manifestations of MTDPS-5 and elucidates the genetic basis of this disorder. In two affected siblings, a novel maternally inherited nonsense variant [c.1234C>T (p.Arg412*)] in the SUCLA2 gene and a unique paternally inherited indel variant (g.48569263-48571020del1758insATGA) were identified. Additionally, the siblings exhibited blood mtDNA content lower than 33% compared to age-matched controls. These findings underscore the importance of assessing SUCLA2 variants in patients with severe early progressive encephalomyopathy, even in the absence of methylmalonic aciduria or mtDNA loss, thereby broaden the mutational spectrum of this gene.
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Affiliation(s)
- Xiaohuan Zhang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center of Medical Genetics, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, China
| | - Guo Zhang
- Dean’s Office, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Li Cao
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center of Medical Genetics, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, China
| | - Wenjing Zhou
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center of Medical Genetics, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, China
| | - Chang Tan
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center of Medical Genetics, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, China
| | - Shi Ma
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center of Medical Genetics, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, China
| | - Jiyun Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center of Medical Genetics, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences, Chengdu, China
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2
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Watanabe M, Sasaki N. Mechanisms and Future Research Perspectives on Mitochondrial Diseases Associated with Isoleucyl-tRNA Synthetase Gene Mutations. Genes (Basel) 2024; 15:894. [PMID: 39062673 PMCID: PMC11276352 DOI: 10.3390/genes15070894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 07/03/2024] [Accepted: 07/05/2024] [Indexed: 07/28/2024] Open
Abstract
Aminoacyl-tRNA synthetases are essential enzymes for the accurate translation of genetic information. IARS1 and IARS2 are isoleucyl-tRNA synthetases functioning in the cytoplasm and mitochondria, respectively, with genetic mutations in these enzymes causing diverse clinical phenotypes in specific organs and tissues. Mutations in IARS1 and IARS2 have recently been linked to mitochondrial diseases. This review aims to explore the relationship between IARS1 and IARS2 and these diseases, providing a comprehensive overview of their association with mitochondrial diseases. Mutations in IARS1 cause weak calf syndrome in cattle and mitochondrial diseases in humans, leading to growth retardation and liver dysfunction. Mutations in IARS2 are associated with Leigh syndrome, craniosynostosis and abnormal genitalia syndrome. Future research is expected to involve genetic analysis of a larger number of patients, identifying new mutations in IARS1 and IARS2, and elucidating their impact on mitochondrial function. Additionally, genetically modified mice and the corresponding phenotypic analysis will serve as powerful tools for understanding the functions of these gene products and unraveling disease mechanisms. This will likely promote the development of new therapies and preventive measures.
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Affiliation(s)
| | - Nobuya Sasaki
- Laboratory of Laboratory Animal Science and Medicine, Kitasato University, 35-1, Higashi-23, Towada 034-8628, Aomori, Japan
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3
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Hegarty R, Thompson RJ. Genetic aetiologies of acute liver failure. J Inherit Metab Dis 2024; 47:582-597. [PMID: 38499319 DOI: 10.1002/jimd.12733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 03/20/2024]
Abstract
Acute liver failure (ALF) is a rare, rapidly evolving, clinical syndrome with devastating consequences where definitive treatment is by emergency liver transplantation. Establishing a diagnosis can be challenging and, historically, the cause of ALF was unidentified in up to half of children. However, recent technological and clinical advances in genomic medicine have led to an increasing proportion being diagnosed with monogenic aetiologies of ALF. The conditions encountered include a diverse group of inherited metabolic disorders each with prognostic and treatment implications. Often these disorders are clinically indistinguishable and may even mimic disorders of immune regulation or red cell disorders. Rapid genomic sequencing for children with ALF is, therefore, a key component in the diagnostic work up today. This review focuses on the monogenic aetiologies of ALF.
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Affiliation(s)
- Robert Hegarty
- Paediatric Liver, GI and Nutrition Centre, King's College Hospital, London, UK
- Institute of Liver Studies, King's College London, London, UK
| | - Richard J Thompson
- Paediatric Liver, GI and Nutrition Centre, King's College Hospital, London, UK
- Institute of Liver Studies, King's College London, London, UK
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4
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Bernardino Gomes TM, Vincent AE, Menger KE, Stewart JB, Nicholls TJ. Mechanisms and pathologies of human mitochondrial DNA replication and deletion formation. Biochem J 2024; 481:683-715. [PMID: 38804971 PMCID: PMC11346376 DOI: 10.1042/bcj20230262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024]
Abstract
Human mitochondria possess a multi-copy circular genome, mitochondrial DNA (mtDNA), that is essential for cellular energy metabolism. The number of copies of mtDNA per cell, and their integrity, are maintained by nuclear-encoded mtDNA replication and repair machineries. Aberrant mtDNA replication and mtDNA breakage are believed to cause deletions within mtDNA. The genomic location and breakpoint sequences of these deletions show similar patterns across various inherited and acquired diseases, and are also observed during normal ageing, suggesting a common mechanism of deletion formation. However, an ongoing debate over the mechanism by which mtDNA replicates has made it difficult to develop clear and testable models for how mtDNA rearrangements arise and propagate at a molecular and cellular level. These deletions may impair energy metabolism if present in a high proportion of the mtDNA copies within the cell, and can be seen in primary mitochondrial diseases, either in sporadic cases or caused by autosomal variants in nuclear-encoded mtDNA maintenance genes. These mitochondrial diseases have diverse genetic causes and multiple modes of inheritance, and show notoriously broad clinical heterogeneity with complex tissue specificities, which further makes establishing genotype-phenotype relationships challenging. In this review, we aim to cover our current understanding of how the human mitochondrial genome is replicated, the mechanisms by which mtDNA replication and repair can lead to mtDNA instability in the form of large-scale rearrangements, how rearranged mtDNAs subsequently accumulate within cells, and the pathological consequences when this occurs.
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Affiliation(s)
- Tiago M. Bernardino Gomes
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- NHS England Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE2 4HH, U.K
| | - Amy E. Vincent
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - Katja E. Menger
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - James B. Stewart
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - Thomas J. Nicholls
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
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5
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Yan W, Xie C, Sun S, Zheng Q, Wang J, Wang Z, Man CH, Wang H, Yang Y, Wang T, Shi L, Zhang S, Huang C, Xu S, Wang YP. SUCLG1 restricts POLRMT succinylation to enhance mitochondrial biogenesis and leukemia progression. EMBO J 2024; 43:2337-2367. [PMID: 38649537 PMCID: PMC11183053 DOI: 10.1038/s44318-024-00101-9] [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: 09/27/2023] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/25/2024] Open
Abstract
Mitochondria are cellular powerhouses that generate energy through the electron transport chain (ETC). The mitochondrial genome (mtDNA) encodes essential ETC proteins in a compartmentalized manner, however, the mechanism underlying metabolic regulation of mtDNA function remains unknown. Here, we report that expression of tricarboxylic acid cycle enzyme succinate-CoA ligase SUCLG1 strongly correlates with ETC genes across various TCGA cancer transcriptomes. Mechanistically, SUCLG1 restricts succinyl-CoA levels to suppress the succinylation of mitochondrial RNA polymerase (POLRMT). Lysine 622 succinylation disrupts the interaction of POLRMT with mtDNA and mitochondrial transcription factors. SUCLG1-mediated POLRMT hyposuccinylation maintains mtDNA transcription, mitochondrial biogenesis, and leukemia cell proliferation. Specifically, leukemia-promoting FMS-like tyrosine kinase 3 (FLT3) mutations modulate nuclear transcription and upregulate SUCLG1 expression to reduce succinyl-CoA and POLRMT succinylation, resulting in enhanced mitobiogenesis. In line, genetic depletion of POLRMT or SUCLG1 significantly delays disease progression in mouse and humanized leukemia models. Importantly, succinyl-CoA level and POLRMT succinylation are downregulated in FLT3-mutated clinical leukemia samples, linking enhanced mitobiogenesis to cancer progression. Together, SUCLG1 connects succinyl-CoA with POLRMT succinylation to modulate mitochondrial function and cancer development.
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Affiliation(s)
- Weiwei Yan
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Chengmei Xie
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Sijun Sun
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
- Department of Gastrointestinal Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Quan Zheng
- Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jingyi Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Zihao Wang
- Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, 200032, Shanghai, China
| | - Cheuk-Him Man
- Division of Haematology, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Haiyan Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Yunfan Yang
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 250012, Jinan, China
| | - Tianshi Wang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China
| | - Leilei Shi
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Shengjie Zhang
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
| | - Chen Huang
- Department of Gastrointestinal Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
| | - Shuangnian Xu
- Department of Hematology, Southwest Hospital, Army Medical University, 400038, Chongqing, China.
| | - Yi-Ping Wang
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
- Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, 200032, Shanghai, China.
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Su L, Sheng H, Li X, Cai Y, Mei H, Cheng J, Li D, Lu Z, Lin Y, Chen X, Peng M, Huang Y, Zhang W, Liu L. Clinical and genetic analysis of methylmalonic aciduria in 60 patients from Southern China: a single center retrospective study. Orphanet J Rare Dis 2024; 19:198. [PMID: 38750596 PMCID: PMC11097538 DOI: 10.1186/s13023-024-03210-0] [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: 01/11/2024] [Accepted: 05/05/2024] [Indexed: 05/18/2024] Open
Abstract
BACKGROUND Methylmalonic aciduria (MMA) is a group of rare genetic metabolic disorders resulting from defects in methylmalonyl coenzyme A mutase (MCM) or intracellular cobalamin (cbl) metabolism. MMA patients show diverse clinical and genetic features across different subtypes and populations. METHODS We retrospectively recruited 60 MMA patients from a single center and diagnosed them based on their clinical manifestations and biochemical assays. We then performed genetic analysis to confirm the diagnosis and identify the causal variants. RESULTS We confirmed the common clinical manifestations of MMA reported previously. We also described four rare MMA cases with unusual symptoms or genetic variants, such as pulmonary hypertension or limb weakness in late-onset patients. We identified 15 MMACHC and 26 MMUT variants in 57 patients, including 6 novel MMUT variants. Two patients had only one MMAA variant each, and one patient had mild MMA due to mitochondrial DNA depletion syndrome caused by a SUCLA2 variant. Among 12 critically ill patients, isolated MMA was associated with higher C3, blood ammonia, and acidosis, while combined MMA was linked to hydrocephalus on skull MRI. MMACHC c.658-660delAAG and MMUT c.1280G > A variants were correlated with more severe phenotypes. CONCLUSIONS Our study demonstrates the clinical and genotypic heterogeneity of MMA patients and indicates that metabolic screening and genetic analysis are useful tools to identify rare cases.
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Affiliation(s)
- Ling Su
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Huiying Sheng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Xiuzhen Li
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Yanna Cai
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Huifen Mei
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Jing Cheng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Duan Li
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Zhikun Lu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Yunting Lin
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Xiaodan Chen
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Minzhi Peng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Yonglan Huang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China
| | - Wen Zhang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China.
| | - Li Liu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Tianhe District, Guangzhou, Guangdong, 510623, P.R. China.
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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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Mahé M, Rios-Fuller TJ, Karolin A, Schneider RJ. Genetics of enzymatic dysfunctions in metabolic disorders and cancer. Front Oncol 2023; 13:1230934. [PMID: 37601653 PMCID: PMC10433910 DOI: 10.3389/fonc.2023.1230934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 07/19/2023] [Indexed: 08/22/2023] Open
Abstract
Inherited metabolic disorders arise from mutations in genes involved in the biogenesis, assembly, or activity of metabolic enzymes, leading to enzymatic deficiency and severe metabolic impairments. Metabolic enzymes are essential for the normal functioning of cells and are involved in the production of amino acids, fatty acids and nucleotides, which are essential for cell growth, division and survival. When the activity of metabolic enzymes is disrupted due to mutations or changes in expression levels, it can result in various metabolic disorders that have also been linked to cancer development. However, there remains much to learn regarding the relationship between the dysregulation of metabolic enzymes and metabolic adaptations in cancer cells. In this review, we explore how dysregulated metabolism due to the alteration or change of metabolic enzymes in cancer cells plays a crucial role in tumor development, progression, metastasis and drug resistance. In addition, these changes in metabolism provide cancer cells with a number of advantages, including increased proliferation, resistance to apoptosis and the ability to evade the immune system. The tumor microenvironment, genetic context, and different signaling pathways further influence this interplay between cancer and metabolism. This review aims to explore how the dysregulation of metabolic enzymes in specific pathways, including the urea cycle, glycogen storage, lysosome storage, fatty acid oxidation, and mitochondrial respiration, contributes to the development of metabolic disorders and cancer. Additionally, the review seeks to shed light on why these enzymes represent crucial potential therapeutic targets and biomarkers in various cancer types.
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Affiliation(s)
| | | | | | - Robert J. Schneider
- Department of Microbiology, Grossman NYU School of Medicine, New York, NY, United States
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9
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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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10
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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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11
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Mitochondrial Neurodegeneration: Lessons from Drosophila melanogaster Models. Biomolecules 2023; 13:biom13020378. [PMID: 36830747 PMCID: PMC9953451 DOI: 10.3390/biom13020378] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/19/2023] Open
Abstract
The fruit fly-i.e., Drosophila melanogaster-has proven to be a very useful model for the understanding of basic physiological processes, such as development or ageing. The availability of straightforward genetic tools that can be used to produce engineered individuals makes this model extremely interesting for the understanding of the mechanisms underlying genetic diseases in physiological models. Mitochondrial diseases are a group of yet-incurable genetic disorders characterized by the malfunction of the oxidative phosphorylation system (OXPHOS), which is the highly conserved energy transformation system present in mitochondria. The generation of D. melanogaster models of mitochondrial disease started relatively recently but has already provided relevant information about the molecular mechanisms and pathological consequences of mitochondrial dysfunction. Here, we provide an overview of such models and highlight the relevance of D. melanogaster as a model to study mitochondrial disorders.
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Abstract
Mitochondrial hepatopathies are a subset of mitochondrial diseases defined by primary dysfunction of hepatocyte mitochondria leading to a phenotype of hepatocyte cell injury, steatosis, or liver failure. Increasingly, the diagnosis is established by new sequencing approaches that combine analysis of both nuclear DNA and mitochondrial DNA and allow for timely diagnosis in most patients. Despite advances in diagnostics, for most affected children their disorders are relentlessly progressive, and result in substantial morbidity and mortality. Treatment remains mainly supportive; however, novel therapeutics and a more definitive role for liver transplantation hold promise for affected children.
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Affiliation(s)
- Mary Ayers
- University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Pittsburgh, PA 15224, USA
| | - Simon P Horslen
- University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Pittsburgh, PA 15224, USA
| | - Anna María Gómez
- University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Pittsburgh, PA 15224, USA
| | - James E Squires
- University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Pittsburgh, PA 15224, USA.
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13
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Chen YM, Chen W, Xu Y, Lu CS, Zhu MM, Sun RY, Wang Y, Chen Y, Shi J, Wang D. Novel compound heterozygous SUCLG1 variants may contribute to mitochondria DNA depletion syndrome-9. Mol Genet Genomic Med 2022; 10:e2010. [PMID: 35762302 PMCID: PMC9482404 DOI: 10.1002/mgg3.2010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 05/18/2022] [Accepted: 06/08/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Succinate-CoA ligase/synthetase (SCS) deficiency is responsible for encephalomyopathy with mitochondrial DNA depletion and mild methylmalonic aciduria. Variants in SUCLG1, the nuclear gene encoding the alpha subunit of the SCS enzyme playing a pivotal role in maintaining mtDNA integrity and stability, are associated with mitochondrial DNA depletion syndrome 9 (MTDPS9). METHODS In this study, we reported an infant with clinical features of MTDPS9 from China. Whole exome sequencing (WES) was used to identify the genetic cause. Bioinformatic analysis and mtDNA level detection were performed to assess pathogenicity. RESULTS The proband manifested with hypotonia, lactic acidosis, mild methylmalonic aciduria, hearing loss and psychomotor retardation. WES identified new compound heterozygous SUCLG1 variants of c.601A>G (p.R201G) in exon 6 and c.871G>C (p.A291P) in exon 8. Computational analysis predicted that these missense variants might alter structure stability and mitochondrial translocation of SUCLG1. qRT-PCR showed 68% depletion of mtDNA content in proband as compared to controls. CONCLUSION Novel compound heterozygous variants c.601A>G (p.R201G) and c.871G>C (p.A291P) in SUCLG1 may cause MTDPS9 in this family. Our finding should be helpful for molecular diagnosis, genetic counseling and clinical management of SCS deficiency disorders.
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Affiliation(s)
- Yi-Ming Chen
- Department of Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Wei Chen
- Department of Radiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yue Xu
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Chao-Sheng Lu
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Mian-Mian Zhu
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Rong-Yue Sun
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yihong Wang
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yuan Chen
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jiaming Shi
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Dan Wang
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
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14
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Jones DE, Jennings EA, Ryan RO. Diversion of Acetyl CoA to 3-Methylglutaconic Acid Caused by Discrete Inborn Errors of Metabolism. Metabolites 2022; 12:metabo12050377. [PMID: 35629880 PMCID: PMC9146172 DOI: 10.3390/metabo12050377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 11/16/2022] Open
Abstract
A growing number of inborn errors of metabolism (IEM) have been identified that manifest 3-methylglutaconic (3MGC) aciduria as a phenotypic feature. In primary 3MGC aciduria, IEM-dependent deficiencies in leucine pathway enzymes prevent catabolism of trans-3MGC CoA. Consequently, this metabolite is converted to 3MGC acid and excreted in urine. In secondary 3MGC aciduria, however, no leucine metabolism pathway enzyme deficiencies exist. These IEMs affect mitochondrial membrane structure, electron transport chain function or ATP synthase subunits. As a result, acetyl CoA oxidation via the TCA cycle slows and acetyl CoA is diverted to trans-3MGC CoA, and then to 3MGC acid. Whereas the trans diastereomer of 3MGC CoA is the only biologically relevant diastereomer, the urine of affected subjects contains both cis- and trans-3MGC acids. Studies have revealed that trans-3MGC CoA is susceptible to isomerization to cis-3MGC CoA. Once formed, cis-3MGC CoA undergoes intramolecular cyclization, forming an anhydride that, upon hydrolysis, yields cis-3MGC acid. Alternatively, cis-3MGC anhydride can acylate protein lysine side chains. Once formed, cis-3MGCylated proteins can be deacylated by the NAD+-dependent enzyme, sirtuin 4. Taken together, the excretion of 3MGC acid in secondary 3MGC aciduria represents a barometer of defective mitochondrial function.
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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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16
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Berardo A, Engelstad K, Hirano M. Advances in Thymidine Kinase 2 Deficiency: Clinical Aspects, Translational Progress, and Emerging Therapies. J Neuromuscul Dis 2022; 9:225-235. [PMID: 35094997 PMCID: PMC9028656 DOI: 10.3233/jnd-210786] [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] [Indexed: 11/15/2022]
Abstract
Defects in the replication, maintenance, and repair of mitochondrial DNA (mtDNA) constitute a growing and genetically heterogeneous group of mitochondrial disorders. Multiple genes participate in these processes, including thymidine kinase 2 (TK2) encoding the mitochondrial matrix protein TK2, a critical component of the mitochondrial nucleotide salvage pathway. TK2 deficiency (TK2d) causes mtDNA depletion, multiple deletions, or both, which manifest predominantly as mitochondrial myopathy. A wide clinical spectrum phenotype includes a severe, rapidly progressive, early onset form (median survival: < 2 years); a less severe childhood-onset form; and a late-onset form with a variably slower rate of progression. Clinical presentation typically includes progressive weakness of limb, neck, facial, oropharyngeal, and respiratory muscle, whereas limb myopathy with ptosis, ophthalmoparesis, and respiratory involvement is more common in the late-onset form. Deoxynucleoside monophosphates and deoxynucleosides that can bypass the TK2 enzyme defect have been assessed in a mouse model, as well as under open-label compassionate use (expanded access) in TK2d patients, indicating clinical efficacy with a favorable side-effect profile. This treatment is currently undergoing testing in clinical trials intended to support approval in the US and European Union (EU). In the early expanded access program, growth differentiation factor 15 (GDF-15) appears to be a useful biomarker that correlates with therapeutic response. With the advent of a specific treatment and given the high morbidity and mortality associated with TK2d, clinicians need to know how to recognize and diagnose this disorder. Here, we summarize translational research about this rare condition emphasizing clinical aspects.
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Affiliation(s)
- Andres Berardo
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
| | - Kristin Engelstad
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
| | - Michio Hirano
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
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17
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Molecular Genetics Overview of Primary Mitochondrial Myopathies. J Clin Med 2022; 11:jcm11030632. [PMID: 35160083 PMCID: PMC8836969 DOI: 10.3390/jcm11030632] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/13/2022] [Accepted: 01/20/2022] [Indexed: 12/29/2022] Open
Abstract
Mitochondrial disorders are the most common inherited conditions, characterized by defects in oxidative phosphorylation and caused by mutations in nuclear or mitochondrial genes. Due to its high energy request, skeletal muscle is typically involved. According to the International Workshop of Experts in Mitochondrial Diseases held in Rome in 2016, the term Primary Mitochondrial Myopathy (PMM) should refer to those mitochondrial disorders affecting principally, but not exclusively, the skeletal muscle. The clinical presentation may include general isolated myopathy with muscle weakness, exercise intolerance, chronic ophthalmoplegia/ophthalmoparesis (cPEO) and eyelids ptosis, or multisystem conditions where there is a coexistence with extramuscular signs and symptoms. In recent years, new therapeutic targets have been identified leading to the launch of some promising clinical trials that have mainly focused on treating muscle symptoms and that require populations with defined genotype. Advantages in next-generation sequencing techniques have substantially improved diagnosis. So far, an increasing number of mutations have been identified as responsible for mitochondrial disorders. In this review, we focused on the principal molecular genetic alterations in PMM. Accordingly, we carried out a comprehensive review of the literature and briefly discussed the possible approaches which could guide the clinician to a genetic diagnosis.
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18
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Maiorana A, Lepri FR, Novelli A, Dionisi-Vici C. Hypoglycaemia Metabolic Gene Panel Testing. Front Endocrinol (Lausanne) 2022; 13:826167. [PMID: 35422763 PMCID: PMC9001947 DOI: 10.3389/fendo.2022.826167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/21/2022] [Indexed: 12/31/2022] Open
Abstract
A large number of inborn errors of metabolism present with hypoglycemia. Impairment of glucose homeostasis may arise from different biochemical pathways involving insulin secretion, fatty acid oxidation, ketone bodies formation and degradation, glycogen metabolism, fructose and galactose metabolism, branched chain aminoacids and tyrosine metabolism, mitochondrial function and glycosylation proteins mechanisms. Historically, genetic analysis consisted of highly detailed molecular testing of nominated single genes. However, more recently, the genetic heterogeneity of these conditions imposed to perform extensive molecular testing within a useful timeframe via new generation sequencing technology. Indeed, the establishment of a rapid diagnosis drives specific nutritional and medical therapies. The biochemical and clinical phenotypes are critical to guide the molecular analysis toward those clusters of genes involved in specific pathways, and address data interpretation regarding the finding of possible disease-causing variants at first reported as variants of uncertain significance in known genes or the discovery of new disease genes. Also, the trio's analysis allows genetic counseling for recurrence risk in further pregnancies. Besides, this approach is allowing to expand the phenotypic characterization of a disease when pathogenic variants give raise to unexpected clinical pictures. Multidisciplinary input and collaboration are increasingly key for addressing the analysis and interpreting the significance of the genetic results, allowing rapidly their translation from bench to bedside.
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Affiliation(s)
- Arianna Maiorana
- Division of Metabolism, Department of Pediatrics Subspecialties, Ospedale Pediatrico Bambino Gesù, IRCCS (Istituto di Ricovero e Cura a Carattere Scientifico), Rome, Italy
- *Correspondence: Arianna Maiorana,
| | - Francesca Romana Lepri
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unity, Ospedale Pediatrico Bambino Gesù, IRCCS (Istituto di Ricovero e Cura a Carattere Scientifico), Rome, Italy
| | - Antonio Novelli
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unity, Ospedale Pediatrico Bambino Gesù, IRCCS (Istituto di Ricovero e Cura a Carattere Scientifico), Rome, Italy
| | - Carlo Dionisi-Vici
- Division of Metabolism, Department of Pediatrics Subspecialties, Ospedale Pediatrico Bambino Gesù, IRCCS (Istituto di Ricovero e Cura a Carattere Scientifico), Rome, Italy
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19
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Jones DE, Klacking E, Ryan RO. Inborn errors of metabolism associated with 3-methylglutaconic aciduria. Clin Chim Acta 2021; 522:96-104. [PMID: 34411555 PMCID: PMC8464523 DOI: 10.1016/j.cca.2021.08.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/11/2021] [Accepted: 08/13/2021] [Indexed: 11/22/2022]
Abstract
A growing number of inborn errors of metabolism (IEM) associated with compromised mitochondrial energy metabolism manifest an unusual phenotypic feature: 3-methylglutaconic (3MGC) aciduria. Two major categories of 3MGC aciduria, primary and secondary, have been described. In primary 3MGC aciduria, IEMs in 3MGC CoA hydratase (AUH) or HMG CoA lyase block leucine catabolism, resulting in a buildup of pathway intermediates, including 3MGC CoA. Subsequent thioester hydrolysis yields 3MGC acid, which is excreted in urine. In secondary 3MGC aciduria, no deficiencies in leucine catabolism enzymes exist and 3MGC CoA is formed de novo from acetyl CoA. In the "acetyl CoA diversion pathway", when IEMs directly, or indirectly, interfere with TCA cycle activity, acetyl CoA accumulates in the matrix space. This leads to condensation of two acetyl CoA to form acetoacetyl CoA, followed by another condensation between acetyl CoA and acetoacetyl CoA to form 3-hydroxy, 3-methylglutaryl (HMG) CoA. Once formed, HMG CoA serves as a substrate for AUH, producing trans-3MGC CoA. Non enzymatic isomerization of trans-3MGC CoA to cis-3MGC CoA precedes intramolecular cyclization to cis-3MGC anhydride plus CoA. Subsequent hydrolysis of cis-3MGC anhydride gives rise to cis-3MGC acid, which is excreted in urine. In reviewing 20 discrete IEMs that manifest secondary 3MGC aciduria, evidence supporting the acetyl CoA diversion pathway was obtained. This biochemical pathway serves as an "overflow valve" in muscle / brain tissue to redirect acetyl CoA to 3MGC CoA when entry to the TCA cycle is impeded.
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Affiliation(s)
- Dylan E Jones
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States
| | - Emma Klacking
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States
| | - Robert O Ryan
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States.
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20
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Luciani A, Denley MCS, Govers LP, Sorrentino V, Froese DS. Mitochondrial disease, mitophagy, and cellular distress in methylmalonic acidemia. Cell Mol Life Sci 2021; 78:6851-6867. [PMID: 34524466 PMCID: PMC8558192 DOI: 10.1007/s00018-021-03934-3] [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] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/18/2021] [Accepted: 08/30/2021] [Indexed: 01/09/2023]
Abstract
Mitochondria—the intracellular powerhouse in which nutrients are converted into energy in the form of ATP or heat—are highly dynamic, double-membraned organelles that harness a plethora of cellular functions that sustain energy metabolism and homeostasis. Exciting new discoveries now indicate that the maintenance of this ever changing and functionally pleiotropic organelle is particularly relevant in terminally differentiated cells that are highly dependent on aerobic metabolism. Given the central role in maintaining metabolic and physiological homeostasis, dysregulation of the mitochondrial network might therefore confer a potentially devastating vulnerability to high-energy requiring cell types, contributing to a broad variety of hereditary and acquired diseases. In this Review, we highlight the biological functions of mitochondria-localized enzymes from the perspective of understanding—and potentially reversing—the pathophysiology of inherited disorders affecting the homeostasis of the mitochondrial network and cellular metabolism. Using methylmalonic acidemia as a paradigm of complex mitochondrial dysfunction, we discuss how mitochondrial directed-signaling circuitries govern the homeostasis and physiology of specialized cell types and how these may be disturbed in disease. This Review also provides a critical analysis of affected tissues, potential molecular mechanisms, and novel cellular and animal models of methylmalonic acidemia which are being used to develop new therapeutic options for this disease. These insights might ultimately lead to new therapeutics, not only for methylmalonic acidemia, but also for other currently intractable mitochondrial diseases, potentially transforming our ability to regulate homeostasis and health.
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Affiliation(s)
- Alessandro Luciani
- Mechanisms of Inherited Kidney Diseases Group, Institute of Physiology, University of Zurich, 8032, Zurich, Switzerland.
| | - Matthew C S Denley
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, University of Zurich, 8032, Zurich, Switzerland
| | - Larissa P Govers
- Mechanisms of Inherited Kidney Diseases Group, Institute of Physiology, University of Zurich, 8032, Zurich, Switzerland
| | - Vincenzo Sorrentino
- Department of Musculo-Skeletal Health, Nestlé Institute of Health Sciences, Nestlé Research, 1015, Lausanne, Switzerland.
| | - D Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, University of Zurich, 8032, Zurich, Switzerland.
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21
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Hadrava Vanova K, Pang Y, Krobova L, Kraus M, Nahacka Z, Boukalova S, Pack SD, Zobalova R, Zhu J, Huynh TT, Jochmanova I, Uher O, Hubackova S, Dvorakova S, Garrett TJ, Ghayee HK, Wu X, Schuster B, Knapp PE, Frysak Z, Hartmann I, Nilubol N, Cerny J, Taieb D, Rohlena J, Neuzil J, Yang C, Pacak K. Germline SUCLG2 Variants in Patients with Pheochromocytoma and Paraganglioma. J Natl Cancer Inst 2021; 114:130-138. [PMID: 34415331 DOI: 10.1093/jnci/djab158] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/14/2020] [Accepted: 08/18/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Pheochromocytoma and paraganglioma (PPGL) are neuroendocrine tumors with frequent mutations in genes linked to the tricarboxylic acid cycle. However, no pathogenic variant has been found to date in succinyl-CoA ligase (SUCL), an enzyme that provides substrate for succinate dehydrogenase (SDH; mitochondrial complex II; CII), a known tumor suppressor in PPGL. METHODS A cohort of 352 subjects with apparently sporadic PPGL underwent genetic testing using a panel of 54 genes developed at the National Institutes of Health, including the SUCLG2 subunit of SUCL. Gene deletion, succinate levels, and protein levels were assessed in tumors where possible. To confirm the possible mechanism, we used a progenitor cell line, hPheo1, derived from a human pheochromocytoma, and ablated and re-expressed SUCLG2. RESULTS We describe eight germline variants in the GTP-binding domain of SUCLG2 in 15 patients (15 of 352, 4.3%) with apparently sporadic PPGL. Analysis of SUCLG2-mutated tumors and SUCLG2-deficient hPheo1 cells revealed absence of SUCLG2 protein, decrease in the level of the SDHB subunit of CII and faulty assembly of the complex, resulting in aberrant respiration and elevated succinate accumulation. CONCLUSIONS Our study suggests SUCLG2 as a novel candidate gene in the genetic landscape of PPGL. Large-scale sequencing may uncover additional cases harboring SUCLG2 variants and provide more detailed information about their prevalence and penetrance.
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Affiliation(s)
- Katerina Hadrava Vanova
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Ying Pang
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Linda Krobova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Michal Kraus
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic.,Faculty of Science, Charles University, Prague, Czech Republic
| | - Zuzana Nahacka
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Stepana Boukalova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Svetlana D Pack
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Renata Zobalova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Jun Zhu
- Systems Biology Center, National Heart Lung Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Thanh-Truc Huynh
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Ivana Jochmanova
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,1st Department of Internal Medicine, Pavol Jozef Safarik University in Kosice, Faculty of Medicine and Teaching Hospital of Louis Pasteur, Kosice, Slovakia
| | - Ondrej Uher
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,Department of Medical Biology, Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Sona Hubackova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Sarka Dvorakova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Timothy J Garrett
- Southeast Center for Integrated Metabolomics, Clinical and Translational Science Institute, University of Florida, Gainesville, FL, USA
| | - Hans K Ghayee
- Department of Medicine, Division of Endocrinology, Malcom Randall VA Medical Center, University of Florida, Gainesville, FL, USA
| | - Xiaolin Wu
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Bjoern Schuster
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Philip E Knapp
- Section of Endocrinology, Boston Medical Center, Boston University, Boston, MA, USA
| | - Zdenek Frysak
- 3rd Department of Internal Medicine, University Hospital and Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
| | - Igor Hartmann
- Department of Urology, University Hospital Olomouc and Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
| | - Naris Nilubol
- Endocrine Surgery Section, Surgical Oncology Program, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jiri Cerny
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - David Taieb
- Department of Nuclear Medicine, La Timone University Hospital, CERIMED, Aix-Marseille University, Marseille, France
| | - Jakub Rohlena
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Jiri Neuzil
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic.,School of Pharmacy and Medical Science, Griffith University, Southport, Qld, Australia
| | - Chunzhang Yang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Karel Pacak
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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22
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Naz S. Molecular genetic landscape of hereditary hearing loss in Pakistan. Hum Genet 2021; 141:633-648. [PMID: 34308486 DOI: 10.1007/s00439-021-02320-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/17/2021] [Indexed: 01/13/2023]
Abstract
Approximately 14.5 million Pakistani individuals have a hearing loss and half of these cases may be due to genetic causes. Though significant progress has been made in uncovering genetic variants for recessively inherited nonsyndromic deafness, Pendred syndrome, and Usher syndromes, the same is not true for dominantly inherited hearing loss, most syndromic cases and deafness with complex inheritance patterns. Variants of 57 genes have been reported to cause nonsyndromic recessive deafness in Pakistan, though most are rare. Variants of just five genes GJB2, HGF, MYO7A, SLC26A4, and TMC1 together explain 57% of profound deafness while those of GJB2, MYO15A, OTOF, SLC26A4, TMC1, and TMPRSS3 account for 47% of moderate to severe hearing loss. In contrast, although variants of at least 39 genes have been implicated in different deafness syndromes, their prevalence in the population and the spectrum of mutations have not been explored. Furthermore, research on genetics of deafness has mostly focused on individuals from the Punjab province and needs to be extended to other regions of Pakistan. Identifying the genes and their variants causing deafness in all ethnic groups is important as it will pinpoint rare as well as recurrent mutations. This information may ultimately help in offering genetic counseling and future treatments.
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Affiliation(s)
- Sadaf Naz
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, 54590, Pakistan.
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Auger C, Vinaik R, Appanna VD, Jeschke MG. Beyond mitochondria: Alternative energy-producing pathways from all strata of life. Metabolism 2021; 118:154733. [PMID: 33631145 PMCID: PMC8052308 DOI: 10.1016/j.metabol.2021.154733] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/09/2021] [Accepted: 02/13/2021] [Indexed: 12/12/2022]
Abstract
It is well-established that mitochondria are the powerhouses of the cell, producing adenosine triphosphate (ATP), the universal energy currency. However, the most significant strengths of the electron transport chain (ETC), its intricacy and efficiency, are also its greatest downfalls. A reliance on metal complexes (FeS clusters, hemes), lipid moities such as cardiolipin, and cofactors including alpha-lipoic acid and quinones render oxidative phosphorylation vulnerable to environmental toxins, intracellular reactive oxygen species (ROS) and fluctuations in diet. To that effect, it is of interest to note that temporal disruptions in ETC activity in most organisms are rarely fatal, and often a redundant number of failsafes are in place to permit continued ATP production when needed. Here, we highlight the metabolic reconfigurations discovered in organisms ranging from parasitic Entamoeba to bacteria such as pseudomonads and then complex eukaryotic systems that allow these species to adapt to and occasionally thrive in harsh environments. The overarching aim of this review is to demonstrate the plasticity of metabolic networks and recognize that in times of duress, life finds a way.
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Affiliation(s)
- Christopher Auger
- Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada
| | - Roohi Vinaik
- University of Toronto, Toronto, Ontario M5S 1A1, Canada
| | | | - Marc G Jeschke
- Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada; University of Toronto, Toronto, Ontario M5S 1A1, Canada.
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Park KC, Krywawych S, Richard E, Desviat LR, Swietach P. Cardiac Complications of Propionic and Other Inherited Organic Acidemias. Front Cardiovasc Med 2020; 7:617451. [PMID: 33415129 PMCID: PMC7782273 DOI: 10.3389/fcvm.2020.617451] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 11/24/2020] [Indexed: 12/12/2022] Open
Abstract
Clinical observations and experimental studies have determined that systemic acid-base disturbances can profoundly affect the heart. A wealth of information is available on the effects of altered pH on cardiac function but, by comparison, much less is known about the actions of the organic anions that accumulate alongside H+ ions in acidosis. In the blood and other body fluids, these organic chemical species can collectively reach concentrations of several millimolar in severe metabolic acidoses, as in the case of inherited organic acidemias, and exert powerful biological actions on the heart that are not intuitive to predict. Indeed, cardiac pathologies, such as cardiomyopathy and arrhythmia, are frequently reported in organic acidemia patients, but the underlying pathophysiological mechanisms are not well established. Research efforts in the area of organic anion physiology have increased dramatically in recent years, particularly for propionate, which accumulates in propionic acidemia, one of the commonest organic acidemias characterized by a high incidence of cardiac disease. This Review provides a comprehensive historical overview of all known organic acidemias that feature cardiac complications and a state-of-the-art overview of the cardiac sequelae observed in propionic acidemia. The article identifies the most promising candidates for molecular mechanisms that become aberrantly engaged by propionate anions (and its metabolites), and discusses how these may result in cardiac derangements in propionic acidemia. Key clinical and experimental findings are considered in the context of potential therapies in the near future.
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Affiliation(s)
- Kyung Chan Park
- Department of Anatomy, Physiology and Genetics, Burdon Sanderson Cardiac Science Centre, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Steve Krywawych
- Department of Chemical Pathology, Great Ormond Street Hospital, London, United Kingdom
| | - Eva Richard
- Centro de Biología Molecular Severo Ochoa, Universidad Autonoma de Madrid-Consejo Superior de Investigaciones Cientificas (UAM-CSIC), Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Lourdes R Desviat
- Centro de Biología Molecular Severo Ochoa, Universidad Autonoma de Madrid-Consejo Superior de Investigaciones Cientificas (UAM-CSIC), Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Pawel Swietach
- Department of Anatomy, Physiology and Genetics, Burdon Sanderson Cardiac Science Centre, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
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25
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SUCLG1 mutations and mitochondrial encephalomyopathy: a case study and review of the literature. Mol Biol Rep 2020; 47:9699-9714. [PMID: 33230783 DOI: 10.1007/s11033-020-05999-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 11/11/2020] [Indexed: 10/22/2022]
Abstract
The mitochondrial encephalomyopathies represent a clinically heterogeneous group of neurodegenerative disorders. The clinical phenotype of patients could be explained by mutations of mitochondria-related genes, notably SUCLG1 and SUCLA2. Here, we presented a 5-year-old boy with clinical features of mitochondrial encephalomyopathy from Iran. Also, a systematic review was performed to explore the involvement of SUCLG1 mutations in published mitochondrial encephalomyopathies cases. Genotyping was performed by implementing whole-exome sequencing. Moreover, quantification of the mtDNA content was performed by real-time qPCR. We identified a novel, homozygote missense variant chr2: 84676796 A > T (hg19) in the SUCLG1 gene. This mutation substitutes Cys with Ser at the 60-position of the SUCLG1 protein. Furthermore, the in-silico analysis revealed that the mutated position in the genome is well conserved in mammalians, that implies mutation in this residue would possibly result in phenotypic consequences. Here, we identified a novel, homozygote missense variant chr2: 84676796 A > T in the SUCLG1 gene. Using a range of experimental and in silico analysis, we found that the mutation might explain the observed phenotype in the family.
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26
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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: 4] [Impact Index Per Article: 1.0] [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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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: 34] [Impact Index Per Article: 8.5] [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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Ortigoza-Escobar JD. A Proposed Diagnostic Algorithm for Inborn Errors of Metabolism Presenting With Movements Disorders. Front Neurol 2020; 11:582160. [PMID: 33281718 PMCID: PMC7691570 DOI: 10.3389/fneur.2020.582160] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/30/2020] [Indexed: 12/13/2022] Open
Abstract
Inherited metabolic diseases or inborn errors of metabolism frequently manifest with both hyperkinetic (dystonia, chorea, myoclonus, ataxia, tremor, etc.) and hypokinetic (rigid-akinetic syndrome) movement disorders. The diagnosis of these diseases is in many cases difficult, because the same movement disorder can be caused by several diseases. Through a literature review, two hundred and thirty one inborn errors of metabolism presenting with movement disorders have been identified. Fifty-one percent of these diseases exhibits two or more movement disorders, of which ataxia and dystonia are the most frequent. Taking into account the wide range of these disorders, a methodical evaluation system needs to be stablished. This work proposes a six-step diagnostic algorithm for the identification of inborn errors of metabolism presenting with movement disorders comprising red flags, characterization of the movement disorders phenotype (type of movement disorder, age and nature of onset, distribution and temporal pattern) and other neurological and non-neurological signs, minimal biochemical investigation to diagnose treatable diseases, radiological patterns, genetic testing and ultimately, symptomatic, and disease-specific treatment. As a strong action, it is emphasized not to miss any treatable inborn error of metabolism through the algorithm.
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Affiliation(s)
- Juan Darío Ortigoza-Escobar
- Movement Disorders Unit, Institut de Recerca Sant Joan de Déu, CIBERER-ISCIII and European Reference Network for Rare Neurological Diseases (ERN-RND), Barcelona, Spain
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29
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Saneto RP. Mitochondrial diseases: expanding the diagnosis in the era of genetic testing. JOURNAL OF TRANSLATIONAL GENETICS AND GENOMICS 2020; 4:384-428. [PMID: 33426505 PMCID: PMC7791531 DOI: 10.20517/jtgg.2020.40] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mitochondrial diseases are clinically and genetically heterogeneous. These diseases were initially described a little over three decades ago. Limited diagnostic tools created disease descriptions based on clinical, biochemical analytes, neuroimaging, and muscle biopsy findings. This diagnostic mechanism continued to evolve detection of inherited oxidative phosphorylation disorders and expanded discovery of mitochondrial physiology over the next two decades. Limited genetic testing hampered the definitive diagnostic identification and breadth of diseases. Over the last decade, the development and incorporation of massive parallel sequencing has identified approximately 300 genes involved in mitochondrial disease. Gene testing has enlarged our understanding of how genetic defects lead to cellular dysfunction and disease. These findings have expanded the understanding of how mechanisms of mitochondrial physiology can induce dysfunction and disease, but the complete collection of disease-causing gene variants remains incomplete. This article reviews the developments in disease gene discovery and the incorporation of gene findings with mitochondrial physiology. This understanding is critical to the development of targeted therapies.
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Affiliation(s)
- Russell P. Saneto
- Center for Integrative Brain Research, Neuroscience Institute, Seattle, WA 98101, USA
- Department of Neurology/Division of Pediatric Neurology, Seattle Children’s Hospital/University of Washington, Seattle, WA 98105, USA
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30
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Kang L, Liu Y, Shen M, Liu Y, He R, Song J, Jin Y, Li M, Zhang Y, Dong H, Liu X, Yan H, Qin J, Zheng H, Chen Y, Li D, Wei H, Zhang H, Sun L, Zhu Z, Liang D, Yang Y. A study on a cohort of 301 Chinese patients with isolated methylmalonic acidemia. J Inherit Metab Dis 2020; 43:409-423. [PMID: 31622506 DOI: 10.1002/jimd.12183] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/28/2019] [Accepted: 10/16/2019] [Indexed: 01/03/2023]
Abstract
Methylmalonic acidemia (MMA) is the most common organic acidemia in China. This study aimed to characterise the genotypic and phenotypic variabilities, and the molecular epidemiology of Chinese patients with isolated MMA. Patients (n = 301) with isolated MMA were diagnosed by clinical examination, biochemical assays, and genetic analysis. Fifty-eight patients (19.3%) were detected by newborn screening and 243 patients (80.7%) were clinically diagnosed after onset. Clinical onset ranged from the age of 3 days to 23 years (mean age = 1.01 ± 0.15 years). Among 234 MMA patients whose detailed clinical data were available, 170 (72.6%) had early onset disease (before the age of 1 year), and 64 (27.4%) had late-onset disease. The 234 MMA patients manifested with neuropsychiatric impairment (65.4%), haematological abnormality (31.6%), renal damage (8.5%), and metabolic crises (67.1%). Haematological abnormality was significantly more common in early-onset patients than that in late-onset patients. The incidence of metabolic crises was significantly high (P < 0.001) in patients with mut type than those with other types of isolated MMA. Variations (n = 122) were identified in MMUT, MMAA, MMAB, MMADHC, SUCLG1, and SUCLA2, of which 45 were novel. c.729_730insTT was the most frequent MMUT mutation, with a significantly higher frequency in our patients than that in 151 reported European patients. The frequency of c.914T>C in MMUT in our cohort was also higher than that in 151 European patients. MMUT mutations c.729_730insTT and c.914T>C are specific for the Chinese population. Our study expanded the spectrum of phenotypes and genotypes in isolated MMA.
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Affiliation(s)
- Lulu Kang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yupeng Liu
- Department of Pediatrics, People's Hospital of Peking University, Beijing, China
| | - Ming Shen
- Translational Medicine Laboratory, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Yi Liu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ruxuan He
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jinqing Song
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ying Jin
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Mengqiu Li
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yao Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hui Dong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xueqin Liu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hui Yan
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jiong Qin
- Department of Pediatrics, People's Hospital of Peking University, Beijing, China
| | - Hong Zheng
- Department of Pediatrics, First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou, China
| | - Yongxing Chen
- Department of Endocrinology and Genetic, Henan Children's Hospital, Zhengzhou, China
| | - Dongxiao Li
- Department of Endocrinology and Genetic, Henan Children's Hospital, Zhengzhou, China
| | - Haiyan Wei
- Department of Endocrinology and Genetic, Henan Children's Hospital, Zhengzhou, China
| | - Huifeng Zhang
- Department of Pediatrics, Hebei Medical University Second Hospital, Shijiazhuang, China
| | - Liying Sun
- Center of Liver Transplantation, Beijing Friendship Hospital, Beijing, China
| | - Zhijun Zhu
- Center of Liver Transplantation, Beijing Friendship Hospital, Beijing, China
| | - Desheng Liang
- Center of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Yanling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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31
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Chinopoulos C. Quantification of mitochondrial DNA from peripheral tissues: Limitations in predicting the severity of neurometabolic disorders and proposal of a novel diagnostic test. Mol Aspects Med 2019; 71:100834. [PMID: 31740079 DOI: 10.1016/j.mam.2019.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/07/2019] [Accepted: 11/12/2019] [Indexed: 11/25/2022]
Abstract
Neurometabolic disorders stem from errors in metabolic processes yielding a neurological phenotype. A subset of those disorders encompasses mitochondrial abnormalities partially due to mitochondrial DNA (mtDNA) depletion. mtDNA depletion can be attributed to inheritance, spontaneous mutations or acquired from drug-related toxicities. In the armamentarium of diagnostic procedures, mtDNA quantification is a standard for disease classification. However, alterations in mtDNA obtained from peripheral tissues such as skin fibroblasts and blood cells do not often reflect the severity of the affected organ, in this case, the brain. The purpose of this review is to highlight the pitfalls of quantitating mtDNA from peripheral -and not limited to-tissues for diagnosing patients suffering from a variety of mtDNA depletion syndromes exhibiting neurologic abnormalities. In lieu, a qualitative test of mitochondrial substrate-level phosphorylation -even from peripheral tissues-reflecting the ability of mitochondria to rely on glutaminolysis in the presence of respiratory chain defects is proposed as a novel diagnostic assessment of mitochondrial functionality.
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Affiliation(s)
- Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Tuzolto St. 37-47, Budapest, 1094, Hungary.
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32
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Cascón A, Remacha L, Calsina B, Robledo M. Pheochromocytomas and Paragangliomas: Bypassing Cellular Respiration. Cancers (Basel) 2019; 11:E683. [PMID: 31100940 PMCID: PMC6562521 DOI: 10.3390/cancers11050683] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/08/2019] [Accepted: 05/13/2019] [Indexed: 12/14/2022] Open
Abstract
Abstract: Pheochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumors that show the highest heritability of all human neoplasms and represent a paradoxical example of genetic heterogeneity. Amongst the elevated number of genes involved in the hereditary predisposition to the disease (at least nineteen) there are eleven tricarboxylic acid (TCA) cycle-related genes, some of which are also involved in the development of congenital recessive neurological disorders and other cancers such as cutaneous and uterine leiomyomas, gastrointestinal tumors and renal cancer. Somatic or germline mutation of genes encoding enzymes catalyzing pivotal steps of the TCA cycle not only disrupts cellular respiration, but also causes severe alterations in mitochondrial metabolite pools. These latter alterations lead to aberrant accumulation of "oncometabolites" that, in the end, may lead to deregulation of the metabolic adaptation of cells to hypoxia, inhibition of the DNA repair processes and overall pathological changes in gene expression. In this review, we will address the TCA cycle mutations leading to the development of PPGL, and we will discuss the relevance of these mutations for the transformation of neural crest-derived cells and potential therapeutic approaches based on the emerging knowledge of underlying molecular alterations.
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Affiliation(s)
- Alberto Cascón
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain.
| | - Laura Remacha
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain.
| | - Bruna Calsina
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain.
| | - Mercedes Robledo
- Hereditary Endocrine Cancer Group, Spanish National Cancer Research Centre (CNIO), 28029 Madrid, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain.
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Niemi AK, Chock VY. Near-Infrared Spectroscopy in the Diagnostic Evaluation of Mitochondrial Disorders: A Neonatal Intensive Care Unit Case Series. J Pediatr 2019; 208:282-286. [PMID: 30853194 DOI: 10.1016/j.jpeds.2019.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 11/28/2019] [Accepted: 01/08/2019] [Indexed: 10/27/2022]
Abstract
We assessed the utility of near-infrared spectroscopy to evaluate neonates with mitochondrial disorders. We observed abnormally high cerebral oxygen saturation levels indicating insufficient tissue oxygen utilization. We propose that near-infrared spectroscopy may be an additional tool in the diagnostic evaluation of a suspected mitochondrial disorder.
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Affiliation(s)
- Anna-Kaisa Niemi
- Division of Neonatology, Rady Children's Hospital San Diego, University of California San Diego, San Diego, CA
| | - Valerie Y Chock
- Department of Pediatrics, Division of Neonatology, Stanford University, Stanford, CA
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Tang J, Hu J, Xue M, Guo Z, Xie M, Zhang B, Zhou Z, Huang W, Hou S. Maternal diet deficient in riboflavin induces embryonic death associated with alterations in the hepatic proteome of duck embryos. Nutr Metab (Lond) 2019; 16:19. [PMID: 30918526 PMCID: PMC6419344 DOI: 10.1186/s12986-019-0345-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 03/05/2019] [Indexed: 12/14/2022] Open
Abstract
Background Maternal riboflavin deficiency (RD) induces embryonic death in poultry. The underlying mechanisms, however, remain to be established and an overview of molecular alterations at the protein level is still lacking. We investigated embryonic hepatic proteome changes induced by maternal RD to explain embryonic death. Methods A total of 80 45-week-old breeding female ducks were divided into two groups of 40 birds each, and all birds were raised individually for 8 weeks. All the female ducks received either a RD or a riboflavin adequate (control, CON) diet, which supplemented the basal diet with 0 or 10 mg riboflavin /kg of diet respectively. Results The riboflavin concentrations of maternal plasma and egg yolk, as well as egg hatchability declined markedly in the RD group compared to those in the CON group after 2 weeks, and declined further over time. The hepatic proteome of E13 viable embryos from 8-week fertile eggs showed that 223 proteins were upregulated and 366 proteins were downregulated (> 1.5-fold change) in the RD group compared to those in the CON group. Pathway analysis showed that differentially expressed proteins were mainly enriched in the fatty acid beta-oxidation, electron transport chain (ETC), and tricarboxylic acid (TCA) cycle. Specifically, all the proteins involved in the fatty acid beta-oxidation and ETC, as well as six out of seven proteins involved in the TCA cycle, were diminished in the RD group, indicating that these processes could be impaired by RD. Conclusion Maternal RD leads to embryonic death of offspring and is associated with impaired energy generation processes, indicated by a number of downregulated proteins involved in the fatty acid beta-oxidation, ETC, and TCA cycle in the hepatic of duck embryos. These findings contribute to our understanding of the mechanisms of liver metabolic disorders due to maternal RD. Electronic supplementary material The online version of this article (10.1186/s12986-019-0345-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jing Tang
- 1State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Jian Hu
- 1State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Ming Xue
- 2National Animal Husbandry Service, Beijing, 100125 China
| | - Zhanbao Guo
- 1State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Ming Xie
- 1State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Bo Zhang
- 1State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Zhengkui Zhou
- 1State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Wei Huang
- 1State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Shuisheng Hou
- 1State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
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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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Sharkia R, Wierenga KJ, Kessel A, Azem A, Bertini E, Carrozzo R, Torraco A, Goffrini P, Ceccatelli Berti C, McCormick ME, Plecko B, Klein A, Abela L, Hengel H, Schöls L, Shalev S, Khayat M, Mahajnah M, Spiegel R. Clinical, radiological, and genetic characteristics of 16 patients with ACO2 gene defects: Delineation of an emerging neurometabolic syndrome. J Inherit Metab Dis 2019; 42:264-275. [PMID: 30689204 DOI: 10.1002/jimd.12022] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 12/07/2018] [Indexed: 12/26/2022]
Abstract
Mitochondrial aconitase is the second enzyme in the tricarboxylic acid (TCA) cycle catalyzing the interconversion of citrate into isocitrate and encoded by the nuclear gene ACO2. A homozygous pathogenic variant in the ACO2 gene was initially described in 2012 resulting in a novel disorder termed "infantile cerebellar retinal degeneration" (ICRD, OMIM#614559). Subsequently, additional studies reported patients with pathogenic ACO2 variants, further expanding the genetic and clinical spectrum of this disorder to include milder and later onset manifestations. Here, we report an international multicenter cohort of 16 patients (of whom 7 are newly diagnosed) with biallelic pathogenic variants in ACO2 gene. Most patients present in early infancy with severe truncal hypotonia, truncal ataxia, variable seizures, evolving microcephaly, and ophthalmological abnormalities of which the most dominant are esotropia and optic atrophy with later development of retinal dystrophy. Most patients remain nonambulatory and do no acquire any language, but a subgroup of patients share a more favorable course. Brain magnetic resonance imaging (MRI) is typically normal within the first months but global atrophy gradually develops affecting predominantly the cerebellum. Ten of our patients were homozygous to the previously reported c.336C>G founder mutation while the other six patients were all compound heterozygotes displaying 10 novel mutations of whom 2 were nonsense predicting a deleterious effect on enzyme function. Structural protein modeling predicted significant impairment in aconitase substrate binding in the additional missense mutations. This study provides the most extensive cohort of patients and further delineates the clinical, radiological, biochemical, and molecular features of ACO2 deficiency.
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Affiliation(s)
- Rajech Sharkia
- Unit of Human Biology and Genetics, The Triangle Regional Research and Development Center, Kafr Qari, Israel
- Unit of Nature Science, Beit-Berl Academic College, Beit-Berl, Israel
| | - Klaas J Wierenga
- Department of Pediatrics, Oklahoma University Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Amit Kessel
- Department of Biochemistry and Molecular Biology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Abdussalam Azem
- Department of Biochemistry and Molecular Biology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Enrico Bertini
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesu' Children's Research Hospital, Rome, Italy
| | - Rosalba Carrozzo
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesu' Children's Research Hospital, Rome, Italy
| | - Alessandra Torraco
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesu' Children's Research Hospital, Rome, Italy
| | - Paola Goffrini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Camilla Ceccatelli Berti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - M Eileen McCormick
- Department of Pediatrics, Oakland University William Beaumont School of Medicine, Rochester, Michigan
| | - Barbara Plecko
- Division of Child Neurology, University Children's Hospital Zurich, Zurich, Switzerland
- Department of Pediatrics, Medical University of Graz, Graz, Austria
| | - Andrea Klein
- Department of Pediatric Neurology, University Children's Hospital Basel and University Children's Hospital, Bern, Switzerland
| | - Lucia Abela
- Molecular Neurosciences, Developmental Neuroscience, UCL Institute of Child Health, London, UK
| | - Holger Hengel
- German Research Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
- Department of Neurodegenerative Diseases and Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Ludger Schöls
- German Research Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
- Department of Neurodegenerative Diseases and Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Stavit Shalev
- Rappaport Faculty of Medicine, Technion- Israel Institute of Technology, Haifa, Israel
- Institute of Medical Genetics, Emek Medical Center, Afula, Israel
| | - Morad Khayat
- Institute of Medical Genetics, Emek Medical Center, Afula, Israel
| | - Muhammad Mahajnah
- Rappaport Faculty of Medicine, Technion- Israel Institute of Technology, Haifa, Israel
- Child Neurology and Development Center, Hillel-Yaffe Medical Center, Hadera, Israel
| | - Ronen Spiegel
- Rappaport Faculty of Medicine, Technion- Israel Institute of Technology, Haifa, Israel
- Department of Pediatrics B, Emek Medical Center, Afula, Israel
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Chinopoulos C, Batzios S, van den Heuvel LP, Rodenburg R, Smeets R, Waterham HR, Turkenburg M, Ruiter JP, Wanders RJA, Doczi J, Horvath G, Dobolyi A, Vargiami E, Wevers RA, Zafeiriou D. Mutated SUCLG1 causes mislocalization of SUCLG2 protein, morphological alterations of mitochondria and an early-onset severe neurometabolic disorder. Mol Genet Metab 2019; 126:43-52. [PMID: 30470562 DOI: 10.1016/j.ymgme.2018.11.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/14/2018] [Accepted: 11/14/2018] [Indexed: 11/19/2022]
Abstract
Succinate-CoA ligase (SUCL) is a heterodimer consisting of an alpha subunit encoded by SUCLG1, and a beta subunit encoded by either SUCLA2 or SUCLG2 catalyzing an ATP- or GTP-forming reaction, respectively, in the mitochondrial matrix. The deficiency of this enzyme represents an encephalomyopathic form of mtDNA depletion syndromes. We describe the fatal clinical course of a female patient with a pathogenic mutation in SUCLG1 (c.626C > A, p.Ala209Glu) heterozygous at the genomic DNA level, but homozygous at the transcriptional level. The patient exhibited early-onset neurometabolic abnormality culminating in severe brain atrophy and dystonia leading to death by the age of 3.5 years. Urine and plasma metabolite profiling was consistent with SUCL deficiency which was confirmed by enzyme analysis and lack of mitochondrial substrate-level phosphorylation (mSLP) in skin fibroblasts. Oxygen consumption- but not extracellular acidification rates were altered only when using glutamine as a substrate, and this was associated with mild mtDNA depletion and no changes in ETC activities. Immunoblot analysis revealed no detectable levels of SUCLG1, while SUCLA2 and SUCLG2 protein expressions were largely reduced. Confocal imaging of triple immunocytochemistry of skin fibroblasts showed that SUCLG2 co-localized only partially with the mitochondrial network which otherwise exhibited an increase in fragmentation compared to control cells. Our results outline the catastrophic consequences of the mutated SUCLG1 leading to strongly reduced SUCL activity, mSLP impairment, mislocalization of SUCLG2, morphological alterations in mitochondria and clinically to a severe neurometabolic disease, but in the absence of changes in mtDNA levels or respiratory complex activities.
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Affiliation(s)
| | - Spyros Batzios
- 1st Department of Pediatrics, "Hippokratio" General Hospital, Aristotle University, Thessaloniki, Greece; Department of Paediatric Metabolic Medicine, Great Ormond Street Hospital, London, UK
| | - Lambertus P van den Heuvel
- Department of Pediatrics, Radboud University Medical Centre, Nijmegen, The Netherlands; Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Richard Rodenburg
- Department of Pediatrics, Radboud University Medical Centre, Nijmegen, The Netherlands; Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Roel Smeets
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centers, University of Amsterdam, The Netherlands
| | - Marjolein Turkenburg
- Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centers, University of Amsterdam, The Netherlands
| | - Jos P Ruiter
- Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centers, University of Amsterdam, The Netherlands
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centers, University of Amsterdam, The Netherlands
| | - Judit Doczi
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
| | - Gergo Horvath
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
| | - Arpad Dobolyi
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Hungarian Academy of Sciences, Eotvos Lorand University, Budapest, Hungary; Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Euthymia Vargiami
- 1st Department of Pediatrics, "Hippokratio" General Hospital, Aristotle University, Thessaloniki, Greece
| | - Ron A Wevers
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands.
| | - Dimitrios Zafeiriou
- 1st Department of Pediatrics, "Hippokratio" General Hospital, Aristotle University, Thessaloniki, Greece.
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Recent topics: the diagnosis, molecular genesis, and treatment of mitochondrial diseases. J Hum Genet 2018; 64:113-125. [PMID: 30459337 DOI: 10.1038/s10038-018-0528-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 10/16/2018] [Accepted: 10/19/2018] [Indexed: 12/30/2022]
Abstract
Mitochondrial diseases are inherited metabolic diseases based on disorders of energy production. The expansion of exome analyses has led to the discovery of many pathogenic nuclear genes associated with these diseases, and research into the pathogenesis of metabolic diseases has progressed. In cases of Leigh syndrome, it is desirable to perform both biochemical and genetic analyses, and pathogenic gene mutations have been identified in over half of the cases analyzed this way. Tandem mass screening and organic acid analyses of urine can sometimes provide important information that leads to the identification of pathogenic genes. Our comprehensive gene analyses have led to the discovery of several novel genes for mitochondrial diseases. Indeed, we reported that GTPBP3 and QRSL1 are involved in mitochondrial DNA maturation. In 2017, as a result of international collaboration, we also identified that mutations in ATAD3 and C1QBP cause mitochondrial disease. Given the varied pathogeneses, treatments for mitochondrial diseases should be specifically tailored to the mutated gene. Clinical trials of sodium pyruvate, 5-aminolevulinic acid with sodium ferrous citrate, and taurine as a treatment for mitochondrial disease have begun in Japan. Given that some mitochondrial diseases may respond well to certain treatments if the pathogenic gene can be identified, an early genetic diagnosis is crucial. Additionally, in Japan, prenatal diagnoses for mitochondrial diseases caused by nuclear genes have been achieved for genes shown to be pathogenic. Treatment and management approaches, including prenatal diagnoses, specifically tailored to the various phenotypes and pathologies of mitochondrial diseases are expected to become increasingly available.
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Poleti MD, Moncau CT, Silva-Vignato B, Rosa AF, Lobo AR, Cataldi TR, Negrão JA, Silva SL, Eler JP, de Carvalho Balieiro JC. Label-free quantitative proteomic analysis reveals muscle contraction and metabolism proteins linked to ultimate pH in bovine skeletal muscle. Meat Sci 2018; 145:209-219. [DOI: 10.1016/j.meatsci.2018.06.041] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 12/23/2022]
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Brasil S, Leal F, Vega A, Navarrete R, Ecay MJ, Desviat LR, Riera C, Padilla N, de la Cruz X, Couce ML, Martin-Hernández E, Morais A, Pedrón C, Peña-Quintana L, Rigoldi M, Specola N, de Almeida IT, Vives I, Yahyaoui R, Rodríguez-Pombo P, Ugarte M, Pérez-Cerda C, Merinero B, Pérez B. Improving the diagnosis of cobalamin and related defects by genomic analysis, plus functional and structural assessment of novel variants. Orphanet J Rare Dis 2018; 13:125. [PMID: 30041674 PMCID: PMC6057060 DOI: 10.1186/s13023-018-0862-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 06/29/2018] [Indexed: 12/04/2022] Open
Abstract
Background Cellular cobalamin defects are a locus and allelic heterogeneous disorder. The gold standard for coming to genetic diagnoses of cobalamin defects has for some time been gene-by-gene Sanger sequencing of individual DNA fragments. Enzymatic and cellular methods are employed before such sequencing to help in the selection of the gene defects to be sought, but this is time-consuming and laborious. Furthermore some cases remain undiagnosed because no biochemical methods have been available to test for cobalamin absorption and transport defects. Results This paper reports the use of massive parallel sequencing of DNA (exome analysis) for the accurate and rapid genetic diagnosis of cobalamin-related defects in a cohort of affected patients. The method was first validated in an initial cohort with different cobalamin defects. Mendelian segregation, the frequency of mutations, and the comprehensive structural and functional analysis of gene variants, identified disease-causing mutations in 12 genes involved in the absorption and synthesis of active cofactors of vitamin B12 (22 cases), and in the non-cobalamin metabolism-related genes ACSF3 (in four biochemically misdiagnosed patients) and SUCLA2 (in one patient with an unusual presentation). We have identified thirteen new variants all classified as pathogenic according to the ACGM recommendation but four were classified as variant likely pathogenic in MUT and SUCLA2. Functional and structural analysis provided evidences to classify them as pathogenic variants. Conclusions The present findings suggest that the technology used is sufficiently sensitive and specific, and the results it provides sufficiently reproducible, to recommend its use as a second-tier test after the biochemical detection of cobalamin disorder markers in the first days of life. However, for accurate diagnoses to be made, biochemical and functional tests that allow comprehensive clinical phenotyping are also needed. Electronic supplementary material The online version of this article (10.1186/s13023-018-0862-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sandra Brasil
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain
| | - Fátima Leal
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain
| | - Ana Vega
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain
| | - Rosa Navarrete
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain
| | - María Jesús Ecay
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain
| | - Lourdes R Desviat
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain
| | - Casandra Riera
- Grupo de Bioinformática Translacional Vall d'Hebron Institute of Research (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Natàlia Padilla
- Grupo de Bioinformática Translacional Vall d'Hebron Institute of Research (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Xavier de la Cruz
- Grupo de Bioinformática Translacional Vall d'Hebron Institute of Research (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain.,ICREA, Barcelona, Spain
| | - Mari Luz Couce
- Hospital Clínico Universitario de Santiago, Santiago de Compostela, CIBERER, Santiago de Compostela, Spain
| | | | - Ana Morais
- Hospital Universitario La Paz, Madrid, Spain
| | | | - Luis Peña-Quintana
- Hospital Universitario Materno Infantil, CIBEROBN, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Miriam Rigoldi
- Center for Rare Disorders, ASST- Monza, Ospedale San Gerardo, Monza, Italy
| | - Norma Specola
- Unidad de Metabolismo Hospital de Niños de La Plata, La Plata, Argentina
| | | | | | - Raquel Yahyaoui
- Hospital Universitario Regional de Málaga, Instituto de Investigación Biomédica de Málaga (IBIMA), Málaga, Spain
| | - Pilar Rodríguez-Pombo
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain
| | - Magdalena Ugarte
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain
| | - Celia Pérez-Cerda
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain
| | - Begoña Merinero
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain
| | - Belén Pérez
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, Madrid, Spain.
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Natural history of mitochondrial disorders: a systematic review. Essays Biochem 2018; 62:423-442. [DOI: 10.1042/ebc20170108] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 05/09/2018] [Accepted: 05/15/2018] [Indexed: 11/17/2022]
Abstract
The natural history of a disease defines the age of onset, presenting features, clinical phenotype, morbidity and mortality outcomes of disease that is unmodified by treatments. A clear understanding of the natural history of mitochondrial disorders is essential for establishing genotype-phenotype–prognosis correlations. We performed a systematic review of the reported natural history of mitochondrial disease by searching the literature for all published natural history studies containing at least 20 individuals. We defined a phenotype as ‘common’ if it was observed in ≥30% of cases in a study, thereby highlighting common and uncommon phenotypes for each disorder. Thirty-seven natural history studies were identified encompassing 29 mitochondrial disease entities. Fifty-nine percent of disorders had an onset before 18 months and 81% before 18 years. Most disorders had multisystemic involvement and most often affected were the central nervous system, eyes, gastrointestinal system, skeletal muscle, auditory system and the heart. Less frequent involvement was seen for respiratory, renal, endocrine, hepatic, haematological and genitourinary systems. Elevated lactate was the most frequent biochemical abnormality, seen in 72% of disorders. Age of death was <1 y in 13% of disorders, <5 y in 57% and <10 y in 74%. Disorders with high mortality rates were generally associated with earlier deaths. The most robust indicators of poor prognosis were early presentation of disease and truncating mutations. A thorough knowledge of natural history has helped to redefine diagnostic criteria for classical clinical syndromes and to establish a clinical baseline for comparison in single-arm clinical trials of novel therapies.
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Eichler FS, Swoboda KJ, Hunt AL, Cestari DM, Rapalino O. Case 38-2017. A 20-Year-Old Woman with Seizures and Progressive Dystonia. N Engl J Med 2017; 377:2376-2385. [PMID: 29236641 DOI: 10.1056/nejmcpc1706109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Florian S Eichler
- From the Departments of Neurology (F.S.E., K.J.S., A.L.H.) and Radiology (O.R.), Massachusetts General Hospital, the Departments of Neurology (F.S.E., K.J.S., A.L.H.), Ophthalmology (D.M.C.), and Radiology (O.R.), Harvard Medical School, and the Department of Ophthalmology, Massachusetts Eye and Ear Infirmary (D.M.C.) - all in Boston
| | - Kathryn J Swoboda
- From the Departments of Neurology (F.S.E., K.J.S., A.L.H.) and Radiology (O.R.), Massachusetts General Hospital, the Departments of Neurology (F.S.E., K.J.S., A.L.H.), Ophthalmology (D.M.C.), and Radiology (O.R.), Harvard Medical School, and the Department of Ophthalmology, Massachusetts Eye and Ear Infirmary (D.M.C.) - all in Boston
| | - Ann L Hunt
- From the Departments of Neurology (F.S.E., K.J.S., A.L.H.) and Radiology (O.R.), Massachusetts General Hospital, the Departments of Neurology (F.S.E., K.J.S., A.L.H.), Ophthalmology (D.M.C.), and Radiology (O.R.), Harvard Medical School, and the Department of Ophthalmology, Massachusetts Eye and Ear Infirmary (D.M.C.) - all in Boston
| | - Dean M Cestari
- From the Departments of Neurology (F.S.E., K.J.S., A.L.H.) and Radiology (O.R.), Massachusetts General Hospital, the Departments of Neurology (F.S.E., K.J.S., A.L.H.), Ophthalmology (D.M.C.), and Radiology (O.R.), Harvard Medical School, and the Department of Ophthalmology, Massachusetts Eye and Ear Infirmary (D.M.C.) - all in Boston
| | - Otto Rapalino
- From the Departments of Neurology (F.S.E., K.J.S., A.L.H.) and Radiology (O.R.), Massachusetts General Hospital, the Departments of Neurology (F.S.E., K.J.S., A.L.H.), Ophthalmology (D.M.C.), and Radiology (O.R.), Harvard Medical School, and the Department of Ophthalmology, Massachusetts Eye and Ear Infirmary (D.M.C.) - all in Boston
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Maalej M, Tej A, Bouguila J, Tilouche S, Majdoub S, Khabou B, Tabbebi M, Felhi R, Ammar M, Mkaouar-Rebai E, Keskes L, Boughamoura L, Fakhfakh F. Clinical, Molecular, and Computational Analysis in two cases with mitochondrial encephalomyopathy associated with SUCLG1 mutation in a consanguineous family. Biochem Biophys Res Commun 2017; 495:1730-1737. [PMID: 29217198 DOI: 10.1016/j.bbrc.2017.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 12/02/2017] [Indexed: 11/28/2022]
Abstract
Deficiency of the mitochondrial enzyme succinyl COA ligase (SUCL) is associated with encephalomyopathic mtDNA depletion syndrome and methylmalonic aciduria. This disorder is caused by mutations in both SUCL subunits genes: SUCLG1 (α subnit) and SUCLA2 (β subnit). We report here, two Tunisian patients belonging to a consanguineous family with mitochondrial encephalomyopathy, hearing loss, lactic acidosis, hypotonia, psychomotor retardation and methylmalonic aciduria. Mutational analysis of SUCLG1 gene showed, for the first time, the presence of c.41T > C in the exon 1 at homozygous state. In-silico analysis revealed that this mutation substitutes a conserved methionine residue to a threonine at position 14 (p.M14T) located at the SUCLG1 protein mitochondrial targeting sequence. Moreover, these analysis predicted that this mutation alter stability structure and mitochondrial translocation of the protein. In Addition, a decrease in mtDNA copy number was revealed by real time PCR in the peripheral blood leukocytes in the two patients compared with controls.
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Affiliation(s)
- Marwa Maalej
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia; Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia.
| | - Amel Tej
- Service de pédiatrie, C.H.U. Farhat Hachad de sousse, University of Sousse, Tunisia
| | - Jihène Bouguila
- Service de pédiatrie, C.H.U. Farhat Hachad de sousse, University of Sousse, Tunisia
| | - Samia Tilouche
- Service de pédiatrie, C.H.U. Farhat Hachad de sousse, University of Sousse, Tunisia
| | - Senda Majdoub
- Service de Radiologie, CHU Farhat Hached, Sousse, University of Sousse, Tunisia
| | - Boudour Khabou
- Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia
| | - Mouna Tabbebi
- Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia
| | - Rahma Felhi
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Marwa Ammar
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Emna Mkaouar-Rebai
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Leila Keskes
- Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia
| | - Lamia Boughamoura
- Service de pédiatrie, C.H.U. Farhat Hachad de sousse, University of Sousse, Tunisia
| | - Faiza Fakhfakh
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia.
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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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Huang R, Liao X, Li Q. Identification and validation of potential prognostic gene biomarkers for predicting survival in patients with acute myeloid leukemia. Onco Targets Ther 2017; 10:5243-5254. [PMID: 29138577 PMCID: PMC5679677 DOI: 10.2147/ott.s147717] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background Molecular analysis is a promising source of clinically useful prognostic biomarkers. The aim of this investigation was to identify prognostic biomarkers for patients with acute myeloid leukemia (AML) by using the gene expression profile dataset from public database. Methods The gene expression profile dataset and corresponding overall survival (OS) information of three cohorts of AML patients from GSE12417 and The Cancer Genome Atlas AML project (TCGA-LAML) were included in the present study. Prognostic gene screening was performed by using a survival package, whereas time-dependent receiver operating characteristic (ROC) curve analysis was performed using the survivalROC package. Results In the three cohorts, 11 genes were identified that were significantly associated with AML OS. A linear prognostic model of the 11 genes was constructed and weighted by regression coefficient (β) from the multivariate Cox regression analyses of GSE12417 HG-U133A cohort to divide patients into high- and low-risk groups. GSE12417 HG-U133 plus 2.0 and TCGA-LAML were validation cohorts. Patients assigned to the high-risk group exhibited poor OS compared to patients in the low-risk group. The 11-gene signature is a prognostic marker of AML and demonstrates good performance for predicting 1-, 3-, and 5-year OS as evaluated by survivalROC in the three cohorts. Conclusion Our study has identified an mRNA signature including 11 genes, which may serve as a potential prognostic marker of AML.
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Affiliation(s)
| | - Xiwen Liao
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, People's Republic of China
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Abstract
Mitochondria are intracellular organelles responsible for adenosine triphosphate production. The strict control of intracellular energy needs require proper mitochondrial functioning. The mitochondria are under dual controls of mitochondrial DNA (mtDNA) and nuclear DNA (nDNA). Mitochondrial dysfunction can arise from changes in either mtDNA or nDNA genes regulating function. There are an estimated ∼1500 proteins in the mitoproteome, whereas the mtDNA genome has 37 proteins. There are, to date, ∼275 genes shown to give rise to disease. The unique physiology of mitochondrial functioning contributes to diverse gene expression. The onset and range of phenotypic expression of disease is diverse, with onset from neonatal to seventh decade of life. The range of dysfunction is heterogeneous, ranging from single organ to multisystem involvement. The complexity of disease expression has severely limited gene discovery. Combining phenotypes with improvements in gene sequencing strategies are improving the diagnosis process. This chapter focuses on the interplay of the unique physiology and gene discovery in the current knowledge of genetically derived mitochondrial disease.
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Affiliation(s)
- Russell P Saneto
- Seattle Children's Hospital/University of Washington, Seattle, WA, United States.
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48
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Loss of succinyl-CoA synthase ADP-forming β subunit disrupts mtDNA stability and mitochondrial dynamics in neurons. Sci Rep 2017; 7:7169. [PMID: 28769029 PMCID: PMC5541051 DOI: 10.1038/s41598-017-05168-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/24/2017] [Indexed: 11/30/2022] Open
Abstract
Succinyl Coenzyme A synthetase (SCS) is a key mitochondrial enzyme. Defected SCS ADP-forming β subunit (SCS A-β) is linked to lethal infantile Leigh or leigh-like syndrome. However, the impacts of SCS A-β deficiency on mitochondria specifically in neurons have not yet been comprehensively investigated. Here, by down-regulating the expression levels of SCS A-β in cultured mouse neurons, we have found that SCS A-β deficiency induces severe mitochondrial dysfunction including lowered oxidative phosphorylation (OXPHOS) efficiency, increased mitochondrial superoxide production, and mtDNA depletion as well as aberrations of mitochondrial fusion and fission proteins, which eventually leads to neuronal stress. Our data also suggest that the deregulation of mitochondrial nucleoside diphosphate kinase (NDPK) together with defects in mitochondrial transcription factors including mitochondrial DNA pol γ and Twinkle contribute to SCS A-β deficiency-mediated mtDNA instability. Furthermore, we have found that SCS A-β deficiency has detrimental influence on neuronal mitochondrial dynamics. Put together, the results have furnished our knowledge on the pathogenesis of SCS A-β deficiency-related mitochondrial diseases and revealed the vital role of SCS A-β in maintaining neuronal mitochondrial quality control and neuronal physiology.
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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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50
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Schottmann G, Picker-Minh S, Schwarz JM, Gill E, Rodenburg RJT, Stenzel W, Kaindl AM, Schuelke M. Recessive mutation in EXOSC3 associates with mitochondrial dysfunction and pontocerebellar hypoplasia. Mitochondrion 2017; 37:46-54. [PMID: 28687512 DOI: 10.1016/j.mito.2017.06.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 06/06/2017] [Accepted: 06/21/2017] [Indexed: 12/13/2022]
Abstract
Recessive mutations in EXOSC3, encoding a subunit of the human RNA exosome complex, cause pontocerebellar hypoplasia type 1b (PCH1B). We report a boy with severe muscular hypotonia, psychomotor retardation, progressive microcephaly, and cerebellar atrophy. Biochemical abnormalities comprised mitochondrial complex I and pyruvate dehydrogenase complex (PDHc) deficiency. Whole exome sequencing uncovered a known EXOSC3 mutation p.(D132A) as the underlying cause. In patient fibroblasts, a large portion of the EXOSC3 protein was trapped in the cytosol. MtDNA copy numbers in muscle were reduced to 35%, but mutations in the mtDNA and in nuclear mitochondrial genes were ruled out. RNA-Seq of patient muscle showed highly increased mRNA copy numbers, especially for genes encoding structural subunits of OXPHOS complexes I, III, and IV, possibly due to reduced degradation by a dysfunctional exosome complex. This is the first case of mitochondrial dysfunction associated with an EXOSC3 mutation, which expands the phenotypic spectrum of PCH1B. We discuss the links between exosome and mitochondrial dysfunction.
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Affiliation(s)
- Gudrun Schottmann
- NeuroCure Clinical Research Center (NCRC), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany; Department of Neuropediatrics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany
| | - Sylvie Picker-Minh
- Department of Neuropediatrics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany; Center for Chronically Sick Children, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany; Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany; Berlin Institute of Health (BIH), Berlin, Germany
| | - Jana Marie Schwarz
- NeuroCure Clinical Research Center (NCRC), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany
| | - Esther Gill
- NeuroCure Clinical Research Center (NCRC), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany
| | - Richard J T Rodenburg
- Radboud Center for Mitochondrial Disorders, Department of Pediatrics, Translational Metabolic Laboratory, Radboudumc, Nijmegen, The Netherlands
| | - Werner Stenzel
- Institute of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany
| | - Angela M Kaindl
- Department of Neuropediatrics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany; Center for Chronically Sick Children, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany; Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany; Berlin Institute of Health (BIH), Berlin, Germany.
| | - Markus Schuelke
- NeuroCure Clinical Research Center (NCRC), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany; Department of Neuropediatrics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Germany.
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