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Armirola-Ricaurte C, Morant L, Adant I, Hamed SA, Pipis M, Efthymiou S, Amor-Barris S, Atkinson D, Van de Vondel L, Tomic A, de Vriendt E, Zuchner S, Ghesquiere B, Hanna M, Houlden H, Lunn MP, Reilly MM, Rasic VM, Jordanova A. Biallelic variants in COX18 cause a mitochondrial disorder primarily manifesting as peripheral neuropathy. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.07.03.24309787. [PMID: 39006432 PMCID: PMC11245062 DOI: 10.1101/2024.07.03.24309787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Defects in mitochondrial dynamics are a common cause of Charcot-Marie-Tooth disease (CMT), while primary deficiencies in the mitochondrial respiratory chain (MRC) are rare and atypical for this etiology. This study aims to report COX18 as a novel CMT-causing gene. This gene encodes an assembly factor of mitochondrial Complex IV (CIV) that translocates the C-terminal tail of MTCO2 across the mitochondrial inner membrane. Exome sequencing was performed in four affected individuals. The patients and available family members underwent thorough neurological and electrophysiological assessment. The impact of one of the identified variants on splicing, protein levels, and mitochondrial bioenergetics was investigated in patient-derived lymphoblasts. The functionality of the mutant protein was assessed using a Proteinase K protection assay and immunoblotting. Neuronal relevance of COX18 was assessed in a Drosophila melanogaster knockdown model. Exome sequencing coupled with homozygosity mapping revealed a homozygous splice variant c.435-6A>G in COX18 in two siblings with early-onset progressive axonal sensory-motor peripheral neuropathy. By querying external databases, we identified two additional families with rare deleterious biallelic variants in COX18 . All affected individuals presented with axonal CMT and some patients also exhibited central nervous system symptoms, such as dystonia and spasticity. Functional characterization of the c.435-6A>G variant demonstrated that it leads to the expression of an alternative transcript that lacks exon 2, resulting in a stable but defective COX18 isoform. The mutant protein impairs CIV assembly and activity, leading to a reduction in mitochondrial membrane potential. Downregulation of the COX18 homolog in Drosophila melanogaster displayed signs of neurodegeneration, including locomotor deficit and progressive axonal degeneration of sensory neurons. Our study presents genetic and functional evidence that supports COX18 as a newly identified gene candidate for autosomal recessive axonal CMT with or without central nervous system involvement. These findings emphasize the significance of peripheral neuropathy within the spectrum of primary mitochondrial disorders and the role of mitochondrial CIV in the development of CMT. Our research has important implications for the diagnostic workup of CMT patients.
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Alici H, Uversky VN, Kang DE, Woo JA, Coskuner-Weber O. The impacts of the mitochondrial myopathy-associated G58R mutation on the dynamic structural properties of CHCHD10. J Biomol Struct Dyn 2024; 42:5607-5616. [PMID: 37349880 DOI: 10.1080/07391102.2023.2227713] [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: 12/16/2022] [Accepted: 06/14/2023] [Indexed: 06/24/2023]
Abstract
The mitochondria are responsible for producing energy within the cell, and in mitochondrial myopathy, there is a defect in the energy production process. The CHCHD10 gene codes for a protein called coiled-coil-helix-coiled-coil-helix domain-containing protein 10 (CHCHD10), which is found in the mitochondria and is involved in the regulation of mitochondrial function. G58R mutation has been shown to disrupt the normal function of CHCHD10, leading to mitochondrial dysfunction and ultimately to the development of mitochondrial myopathy. The structures of G58R mutant CHCHD10 and how G58R mutation impacts the wild-type CHCHD10 protein at the monomeric level are unknown. To address this problem, we conducted homology modeling, multiple run molecular dynamics simulations and bioinformatics calculations. We represent herein the structural ensemble properties of the G58R mutant CHCHD10 (CHCHD10G58R) in aqueous solution. Moreover, we describe the impacts of G58R mutation on the structural ensembles of wild-type CHCHD10 (CHCHD10WT) in aqueous solution. The dynamics properties as well as structural properties of CHCHD10WT are impacted by the mitochondrial myopathy-related G58R mutation. Specifically, the secondary and tertiary structure properties, root mean square fluctuations, Ramachandran diagrams and results from principal component analysis demonstrate that the CHCHD10WT and CHCHD10G58R proteins possess different structural ensemble characteristics and describe the impacts of G58R mutation on CHCHD10WT. These findings may be helpful for designing new treatments for mitochondrial myopathy.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Hakan Alici
- Faculty of Sciences, Department of Physics, Zonguldak Bulent Ecevit University, Zonguldak, Turkey
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - David E Kang
- School of Medicine, Department of Pathology, Case Western Reserve University, Cleveland, USA
- Louis Stokes Cleveland VA Medical Center, Cleveland, USA
| | - Junga Alexa Woo
- School of Medicine, Department of Pathology, Case Western Reserve University, Cleveland, USA
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Beecher G, Gavrilova RH, Mandrekar J, Naddaf E. Mitochondrial myopathies diagnosed in adulthood: clinico-genetic spectrum and long-term outcomes. Brain Commun 2024; 6:fcae041. [PMID: 38434220 PMCID: PMC10906953 DOI: 10.1093/braincomms/fcae041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 12/14/2023] [Accepted: 02/12/2024] [Indexed: 03/05/2024] Open
Abstract
Mitochondrial myopathies are frequently recognized in childhood as part of a broader multisystem disorder and often overlooked in adulthood. Herein, we describe the phenotypic and genotypic spectrum and long-term outcomes of mitochondrial myopathies diagnosed in adulthood, focusing on neuromuscular features, electrodiagnostic and myopathological findings and survival. We performed a retrospective chart review of adult patients diagnosed with mitochondrial myopathy at Mayo Clinic (2005-21). We identified 94 patients. Median time from symptom onset to diagnosis was 11 years (interquartile range 4-21 years). Median age at diagnosis was 48 years (32-63 years). Primary genetic defects were identified in mitochondrial DNA in 48 patients (10 with single large deletion, 38 with point mutations) and nuclear DNA in 29. Five patients had multiple mitochondrial DNA deletions or depletion without nuclear DNA variants. Twelve patients had histopathological features of mitochondrial myopathy without molecular diagnosis. The most common phenotypes included multisystem disorder (n = 30); mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (14); limb myopathy (13); chronic progressive external ophthalmoplegia (12); and chronic progressive external ophthalmoplegia-plus (12). Isolated skeletal muscle manifestations occurred in 27%. Sixty-nine per cent had CNS and 21% had cardiac involvement. Mutations most frequently involved MT-TL1 (27) and POLG (17); however, a wide spectrum of established and novel molecular defects, with overlapping phenotypes, was identified. Electrodiagnostic studies identified myopathy (77%), fibrillation potentials (27%) and axonal peripheral neuropathy (42%, most common with nuclear DNA variants). Among 42 muscle biopsies available, median percentage counts were highest for cytochrome C oxidase negative fibres (5.1%) then ragged blue (1.4%) and ragged red fibres (0.5%). Skeletal muscle weakness was mild and slowly progressive (decline in strength summated score of 0.01/year). Median time to gait assistance was 5.5 years from diagnosis and 17 years from symptom onset. Thirty patients died, with median survival of 33.4 years from symptom onset and 10.9 years from diagnosis. Median age at death was 55 years. Cardiac involvement was associated with increased mortality [hazard ratio 2.36 (1.05, 5.29)]. There was no difference in survival based on genotype or phenotype. Despite the wide phenotypic and genotypic spectrum, mitochondrial myopathies in adults share similar features with slowly progressive limb weakness, contrasting with common multiorgan involvement and high mortality.
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Affiliation(s)
- Grayson Beecher
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada T6G 2G3
| | - Ralitza H Gavrilova
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Jay Mandrekar
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Elie Naddaf
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
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Lin Y, Wang J, Ren H, Ma X, Wang W, Zhao Y, Xu Z, Liu S, Wang W, Xu X, Wang B, Zhao D, Wang D, Li W, Liu F, Zhao Y, Lu J, Yan C, Ji K. Mitochondrial myopathy without extraocular muscle involvement: a unique clinicopathologic profile. J Neurol 2024; 271:864-876. [PMID: 37847292 DOI: 10.1007/s00415-023-12005-5] [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: 07/19/2023] [Revised: 09/12/2023] [Accepted: 09/14/2023] [Indexed: 10/18/2023]
Abstract
OBJECTIVE Mitochondrial myopathy without extraocular muscles involvement (MiMy) represents a distinct form of mitochondrial disorder predominantly affecting proximal/distal or axial muscles, with its phenotypic, genotypic features, and long-term prognosis poorly understood. METHODS A cross-sectional study conducted at a national diagnostic center for mitochondrial disease involved 47 MiMy patients, from a cohort of 643 mitochondrial disease cases followed up at Qilu Hospital from January 1, 2000, to January 1, 2021. We compared the clinical, pathological, and genetic features of MiMy to progressive external ophthalmoplegia (PEO) and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) patients. RESULTS MiMy patients demonstrated a more pronounced muscle involvement syndrome, with lower 6MWT scores, higher FSS, and lower BMI compared to PEO and MELAS patients. Serum levels of creatinine kinase (CK), lactate, and growth and differentiation factor 15 (GDF15) were substantially elevated in MiMy patients. Nearly a third (31.9%) displayed signs of subclinical peripheral neuropathy, mostly axonal neuropathy. Muscle biopsies revealed that cytochrome c oxidase strong (COX-s) ragged-red fibers (RRFs) were a typical pathological feature in MiMy patients. Genetic analysis predominantly revealed mtDNA point pathogenic variants (59.6%) and less frequently single (12.8%) or multiple (4.2%) mtDNA deletions. During the follow-up, a majority (76.1%) of MiMy patients experienced stabilization or improvement after therapeutic intervention. CONCLUSIONS This study provides a comprehensive profile of MiMy through a large patient cohort, elucidating its unique clinical, genetic, and pathological features. These findings offer significant insights into the diagnostic and therapeutic management of MiMy, ultimately aiming to ameliorate patient outcomes and enhance the quality of life.
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Affiliation(s)
- Yan Lin
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Jiayin Wang
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Hong Ren
- Department of Neurology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, 250012, Shandong, China
| | - Xiaotian Ma
- Mitochondrial Medicine Laboratory, Qilu Hospital (Qingdao), Shandong University, Qingdao, 266035, Shandong, China
| | - Wei Wang
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Ying Zhao
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Zhihong Xu
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Shuangwu Liu
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Wenqing Wang
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Xuebi Xu
- Department of Neurology, First Affiliated Hospital of Wenzhou Medical University, Nanbaixiang Street, Ouhai District, Wenzhou, 325000, China
| | - Bin Wang
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Dandan Zhao
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Dongdong Wang
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Wei Li
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Fuchen Liu
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Yuying Zhao
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
| | - Jianqiang Lu
- Department of Pathology and Molecular Medicine, Neuropathology Section, McMaster University, Hamilton, ON, Canada
| | - Chuanzhu Yan
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China
- Mitochondrial Medicine Laboratory, Qilu Hospital (Qingdao), Shandong University, Qingdao, 266035, Shandong, China
- Brain Science Research Institute, Shandong University, Jinan, 250012, Shandong, China
| | - Kunqian Ji
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road, Jinan, 250012, Shandong, China.
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Cao X, Zeng L, Lu Z, Fan J, Tan S, Zhang M, Yin Z. A female case report of LGMD2B with compound heterozygous mutations of the DYSF gene and asymptomatic mutation of the X-linked DMD gene. Front Neurol 2023; 14:1213090. [PMID: 37830096 PMCID: PMC10564995 DOI: 10.3389/fneur.2023.1213090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 06/15/2023] [Indexed: 10/14/2023] Open
Abstract
We report the case of a 31-year-old Chinese woman with a chief complaint of weakness in the lower limbs, which was diagnosed as limb-girdle muscular dystrophy 2B (LGMD2B) with compound heterozygous mutations of the DYSF gene. Meanwhile, this woman is an asymptomatic carrier with the mutation of the X-linked DMD gene. The electromyography, muscle MRI, and muscle biopsy indicated a chronic myogenic injury with dysferlin deletion. As a result of genetic testing, compound heterozygous G-to-T base substitution at position 5,497 in exon 49 of the DYSF gene, leading to a codon change from glutamic acid to termination codon at position 1,833, and a heterozygous C-to-G base change at position 4,638 + 8 in intron 42 of the DYSF gene with a consequence of splice, which has never been reported, were identified as candidate causative mutations. Unfortunately, DMD gene mutation c.3921+12A>G of the DMD gene on the X chromosome was also found in this patient. Finally, the patient was diagnosed as LGMD2B clinically and genetically. In the previous 2 years, the patient's lower limb weakness became slightly worse, resulting in even the total distance walked than before. Fortunately, during the follow-up, her son had not shown slowness or limitation of movement. Genetic testing by next-generation sequencing confirmed the final diagnosis of LGMD2B, and we identified the novel compound heterozygous variants in the DYSF gene, which is of great significance to the accurate diagnosis of genetically coded diseases. Much attention needs to be paid in clinics toward hereditary neuromuscular diseases with multiple pathogenic gene mutations. Genetic counseling and clinical follow-up should be the priorities in future, and promising treatments are also worth exploring.
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Affiliation(s)
- Xiaojie Cao
- Department of Neurology, The General Hospital of Western Theater Command, Chengdu, Sichuan Province, China
| | - Li Zeng
- Department of Neurology, Sichuan Academy of Medical Science and Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Zhijie Lu
- Department of Neurology, The General Hospital of Western Theater Command, Chengdu, Sichuan Province, China
| | - Jin Fan
- Department of Neurology, The General Hospital of Western Theater Command, Chengdu, Sichuan Province, China
| | - Song Tan
- Department of Neurology, Sichuan Academy of Medical Science and Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Mingjie Zhang
- Department of Neurology, The General Hospital of Western Theater Command, Chengdu, Sichuan Province, China
| | - Zegang Yin
- Department of Neurology, The General Hospital of Western Theater Command, Chengdu, Sichuan Province, China
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Dong H, Tsai SY. Mitochondrial Properties in Skeletal Muscle Fiber. Cells 2023; 12:2183. [PMID: 37681915 PMCID: PMC10486962 DOI: 10.3390/cells12172183] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/16/2023] [Accepted: 08/24/2023] [Indexed: 09/09/2023] Open
Abstract
Mitochondria are the primary source of energy production and are implicated in a wide range of biological processes in most eukaryotic cells. Skeletal muscle heavily relies on mitochondria for energy supplements. In addition to being a powerhouse, mitochondria evoke many functions in skeletal muscle, including regulating calcium and reactive oxygen species levels. A healthy mitochondria population is necessary for the preservation of skeletal muscle homeostasis, while mitochondria dysregulation is linked to numerous myopathies. In this review, we summarize the recent studies on mitochondria function and quality control in skeletal muscle, focusing mainly on in vivo studies of rodents and human subjects. With an emphasis on the interplay between mitochondrial functions concerning the muscle fiber type-specific phenotypes, we also discuss the effect of aging and exercise on the remodeling of skeletal muscle and mitochondria properties.
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Affiliation(s)
- Han Dong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore;
| | - Shih-Yin Tsai
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore;
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore
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Alves CAPF, Zandifar A, Peterson JT, Tara SZ, Ganetzky R, Viaene AN, Andronikou S, Falk MJ, Vossough A, Goldstein AC. MELAS: Phenotype Classification into Classic-versus-Atypical Presentations. AJNR Am J Neuroradiol 2023; 44:602-610. [PMID: 37024306 PMCID: PMC10171385 DOI: 10.3174/ajnr.a7837] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/24/2023] [Indexed: 04/08/2023]
Abstract
BACKGROUND AND PURPOSE An increased number of pathogenic variants have been described in mitochondrial encephalomyopathy lactic acidosis and strokelike episodes (MELAS). Different imaging presentations have emerged in parallel with a growing recognition of clinical and outcome variability, which pose a diagnostic challenge to neurologists and radiologists and may impact an individual patient's response to therapeutic interventions. By evaluating clinical, neuroimaging, laboratory, and genetic findings, we sought to improve our understanding of the sources of potential phenotype variability in patients with MELAS. MATERIALS AND METHODS This retrospective single-center study included individuals who had confirmed mitochondrial DNA pathogenic variants and a diagnosis of MELAS and whose data were reviewed from January 2000 through November 2021. The approach included a review of clinical, neuroimaging, laboratory, and genetic data, followed by an unsupervised hierarchical cluster analysis looking for sources of phenotype variability in MELAS. Subsequently, experts identified "victory-variables" that best differentiated MELAS cohort clusters. RESULTS Thirty-five patients with a diagnosis of mitochondrial DNA-based MELAS (median age, 12 years; interquartile range, 7-24 years; 24 female) were eligible for this study. Fifty-three discrete variables were evaluated by an unsupervised cluster analysis, which revealed that two distinct phenotypes exist among patients with MELAS. After experts reviewed the variables, they selected 8 victory-variables with the greatest impact in determining the MELAS subgroups: developmental delay, sensorineural hearing loss, vision loss in the first strokelike episode, Leigh syndrome overlap, age at the first strokelike episode, cortical lesion size, regional brain distribution of lesions, and genetic groups. Ultimately, 2-step differentiating criteria were defined to classify atypical MELAS. CONCLUSIONS We identified 2 distinct patterns of MELAS: classic MELAS and atypical MELAS. Recognizing different patterns in MELAS presentations will enable clinical and research care teams to better understand the natural history and prognosis of MELAS and identify the best candidates for specific therapeutic interventions.
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Affiliation(s)
- C A P F Alves
- From the Division of Neuroradiology (C.A.P.F.A., A.Z., S.A., A.V.), Department of Radiology
| | - A Zandifar
- From the Division of Neuroradiology (C.A.P.F.A., A.Z., S.A., A.V.), Department of Radiology
| | - J T Peterson
- Mitochondrial Medicine Frontier Program (J.T.P., S.Z.T., R.G., M.J.F., A.C.G.), Division of Human Genetics, Department of Pediatrics
| | - S Z Tara
- Mitochondrial Medicine Frontier Program (J.T.P., S.Z.T., R.G., M.J.F., A.C.G.), Division of Human Genetics, Department of Pediatrics
| | - R Ganetzky
- Mitochondrial Medicine Frontier Program (J.T.P., S.Z.T., R.G., M.J.F., A.C.G.), Division of Human Genetics, Department of Pediatrics
- Departments of Pediatrics (R.G., M.J.F., A.C.G.)
| | - A N Viaene
- Department of Pathology and Laboratory Medicine (A.N.V.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Pathology and Laboratory Medicine (A.N.V.)
| | - S Andronikou
- From the Division of Neuroradiology (C.A.P.F.A., A.Z., S.A., A.V.), Department of Radiology
- Radiology (S.A., A.V.), Perelman School of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - M J Falk
- Mitochondrial Medicine Frontier Program (J.T.P., S.Z.T., R.G., M.J.F., A.C.G.), Division of Human Genetics, Department of Pediatrics
- Departments of Pediatrics (R.G., M.J.F., A.C.G.)
| | - A Vossough
- From the Division of Neuroradiology (C.A.P.F.A., A.Z., S.A., A.V.), Department of Radiology
- Radiology (S.A., A.V.), Perelman School of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - A C Goldstein
- Mitochondrial Medicine Frontier Program (J.T.P., S.Z.T., R.G., M.J.F., A.C.G.), Division of Human Genetics, Department of Pediatrics
- Departments of Pediatrics (R.G., M.J.F., A.C.G.)
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Horvath R, Medina J, Reilly MM, Shy ME, Zuchner S. Peripheral neuropathy in mitochondrial disease. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:99-116. [PMID: 36813324 DOI: 10.1016/b978-0-12-821751-1.00014-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Mitochondria are essential for the health and viability of both motor and sensory neurons and their axons. Processes that disrupt their normal distribution and transport along axons will likely cause peripheral neuropathies. Similarly, mutations in mtDNA or nuclear encoded genes result in neuropathies that either stand alone or are part of multisystem disorders. This chapter focuses on the more common genetic forms and characteristic clinical phenotypes of "mitochondrial" peripheral neuropathies. We also explain how these various mitochondrial abnormalities cause peripheral neuropathy. In a patient with a neuropathy either due to a mutation in a nuclear or an mtDNA gene, clinical investigations aim to characterize the neuropathy and make an accurate diagnosis. In some patients, this may be relatively straightforward, where a clinical assessment and nerve conduction studies followed by genetic testing is all that is needed. In others, multiple investigations including a muscle biopsy, CNS imaging, CSF analysis, and a wide range of metabolic and genetic tests in blood and muscle may be needed to establish diagnosis.
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Affiliation(s)
- Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, John van Geest Centre for Brain Repair, Cambridge, United Kingdom.
| | - Jessica Medina
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Mary M Reilly
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Michael E Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, United States
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9
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Movement disorders and neuropathies: overlaps and mimics in clinical practice. J Neurol 2022; 269:4646-4662. [PMID: 35657406 DOI: 10.1007/s00415-022-11200-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 10/18/2022]
Abstract
Movement disorders as well as peripheral neuropathies are extremely frequent in the general population; therefore, it is not uncommon to encounter patients with both these conditions. Often, the coexistence is coincidental, due to the high incidence of common causes of peripheral neuropathy, such as diabetes and other age-related disorders, as well as of Parkinson disease (PD), which has a typical late onset. Nonetheless, there is broad evidence that PD patients may commonly develop a sensory and/or autonomic polyneuropathy, triggered by intrinsic and/or extrinsic mechanisms. Similarly, some peripheral neuropathies may develop some movement disorders in the long run, such as tremor, and rarely dystonia and myoclonus, suggesting that central mechanisms may ensue in the pathogenesis of these diseases. Although rare, several acquired or hereditary causes may be responsible for the combination of movement and peripheral nerve disorders as a unique entity, some of which are potentially treatable, including paraneoplastic, autoimmune and nutritional aetiologies. Finally, genetic causes should be pursued in case of positive family history, young onset or multisystemic involvement, and examined for neuroacanthocytosis, spinocerebellar ataxias, mitochondrial disorders and less common causes of adult-onset cerebellar ataxias and spastic paraparesis. Deep phenotyping in terms of neurological and general examination, as well as laboratory tests, neuroimaging, neurophysiology, and next-generation genetic analysis, may guide the clinician toward the correct diagnosis and management.
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10
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Thongboonkerd V, Chaiyarit S. Gel-Based and Gel-Free Phosphoproteomics to Measure and Characterize Mitochondrial Phosphoproteins. Curr Protoc 2022; 2:e390. [PMID: 35275445 DOI: 10.1002/cpz1.390] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The mitochondrion is a key intracellular organelle regulating metabolic processes, oxidative stress, energy production, calcium homeostasis, and cell survival. Protein phosphorylation plays an important role in regulating mitochondrial functions and cellular signaling pathways. Dysregulation of protein phosphorylation status can cause protein malfunction and abnormal signal transduction, leading to organ dysfunction and disease. Investigating the mitochondrial phosphoproteins is therefore crucial to better understand the molecular and pathogenic mechanisms of many metabolic disorders. Conventional analyses of phosphoproteins, for instance, via western blotting, can be done only for proteins for which specific antibodies to their phosphorylated forms are available. Moreover, such an approach is not suitable for large-scale study of phosphoproteins. Currently, proteomics represents an important tool for large-scale analysis of proteins and their post-translational modifications, including phosphorylation. Here, we provide step-by-step protocols for the proteomics analysis of mitochondrial phosphoproteins (the phosphoproteome), using renal tubular cells as an example. These protocols include methods to effectively isolate mitochondria and to validate the efficacy of mitochondrial enrichment as well as its purity. We also provide detailed protocols for performing both gel-based and gel-free phosphoproteome analyses. The gel-based analysis involves two-dimensional gel electrophoresis and phosphoprotein-specific staining, followed by protein identification via mass spectrometry, whereas the gel-free approach is based on in-solution mass spectrometric identification of specific phosphorylation sites and residues. In all, these approaches allow large-scale analyses of mitochondrial phosphoproteins that can be applied to other cells and tissues of interest. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Mitochondrial isolation/purification from renal tubular cells Support Protocol: Validation of enrichment efficacy and purity of mitochondrial isolation Basic Protocol 2: Gel-based phosphoproteome analysis Basic Protocol 3: Gel-free phosphoproteome analysis.
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Affiliation(s)
- Visith Thongboonkerd
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Sakdithep Chaiyarit
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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Tankeu AT, Tran C. [Chronic Fatigue: When to Suspect an Inherited Metabolic Disease?]. PRAXIS 2022; 110:38-43. [PMID: 34983209 DOI: 10.1024/1661-8157/a003772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Chronic Fatigue: When to Suspect an Inherited Metabolic Disease? Abstract. Chronic fatigue is a non-specific symptom, frequent in outpatient adults' consultations. Persistent physical fatigue of unknown etiology should prompt the search for rare diseases including inherited metabolic disorder (IMD) after elimination of common causes. The main characteristic of chronic fatigue in IMD is its dynamic nature, worsened by circumstances leading to an increased metabolism such as physical exertion, cold, fasting or infection. IMD leading to chronic fatigue are metabolic myopathies, in particular glycogen storage disease affecting muscle, fatty acid oxidation disorders and mitochondrial diseases. The diagnosis is confirmed by specific biochemical and/or molecular analyzes with multidisciplinary management.
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Affiliation(s)
- Aurel T Tankeu
- Centre des maladies moléculaires (CMM), Service de Médecine Génétique, Centre Hospitalier et Universitaire Vaudois (CHUV), Lausanne
| | - Christel Tran
- Centre des maladies moléculaires (CMM), Service de Médecine Génétique, Centre Hospitalier et Universitaire Vaudois (CHUV), Lausanne
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Tankeu AT, Tran C. [Chronic Fatigue: When to Suspect an Inherited Metabolic Disease?]. PRAXIS 2022; 110:1-6. [PMID: 34983208 DOI: 10.1024/1661-8157/a003773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Chronic Fatigue: When to Suspect an Inherited Metabolic Disease? Abstract. Chronic fatigue is a non-specific symptom, frequent in outpatient adults' consultations. Persistent physical fatigue of unknown etiology should prompt the search for rare diseases including inherited metabolic disorder (IMD) after elimination of common causes. The main characteristic of chronic fatigue in IMD is its dynamic nature, worsened by circumstances leading to an increased metabolism such as physical exertion, cold, fasting or infection. IMD leading to chronic fatigue are metabolic myopathies, in particular glycogen storage disease affecting muscle, fatty acid oxidation disorders and mitochondrial diseases. The diagnosis is confirmed by specific biochemical and/or molecular analyzes with multidisciplinary management.
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Affiliation(s)
- Aurel T Tankeu
- Zentrum für Molekularkrankheiten (CMM), Abteilung für genetische Medizin, Centre Hospitalier et Universitaire Vaudois (CHUV), Lausanne
| | - Christel Tran
- Zentrum für Molekularkrankheiten (CMM), Abteilung für genetische Medizin, Centre Hospitalier et Universitaire Vaudois (CHUV), Lausanne
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Gayathri N, Deepha S, Sharma S. Diagnosis of primary mitochondrial disorders -Emphasis on myopathological aspects. Mitochondrion 2021; 61:69-84. [PMID: 34592422 DOI: 10.1016/j.mito.2021.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/03/2021] [Accepted: 09/22/2021] [Indexed: 12/29/2022]
Abstract
Mitochondrial disorders are one of the most common neurometabolic disorders affecting all age groups. The phenotype-genotype heterogeneity in these disorders can be attributed to the dual genetic control on mitochondrial functions, posing a challenge for diagnosis. Though the advancement in the high-throughput sequencing and other omics platforms resulted in a "genetics-first" approach, the muscle biopsy remains the benchmark in most of the mitochondrial disorders. This review focuses on the myopathological aspects of primary mitochondrial disorders. The utility of muscle biopsy is not limited to analyse the structural abnormalities; rather it also proves to be a potential tool to understand the deranged sub-cellular functions.
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Affiliation(s)
- Narayanappa Gayathri
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India.
| | - Sekar Deepha
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India
| | - Shivani Sharma
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India
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Sharma G, Pfeffer G, Shutt TE. Genetic Neuropathy Due to Impairments in Mitochondrial Dynamics. BIOLOGY 2021; 10:268. [PMID: 33810506 PMCID: PMC8066130 DOI: 10.3390/biology10040268] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/19/2021] [Accepted: 03/21/2021] [Indexed: 12/12/2022]
Abstract
Mitochondria are dynamic organelles capable of fusing, dividing, and moving about the cell. These properties are especially important in neurons, which in addition to high energy demand, have unique morphological properties with long axons. Notably, mitochondrial dysfunction causes a variety of neurological disorders including peripheral neuropathy, which is linked to impaired mitochondrial dynamics. Nonetheless, exactly why peripheral neurons are especially sensitive to impaired mitochondrial dynamics remains somewhat enigmatic. Although the prevailing view is that longer peripheral nerves are more sensitive to the loss of mitochondrial motility, this explanation is insufficient. Here, we review pathogenic variants in proteins mediating mitochondrial fusion, fission and transport that cause peripheral neuropathy. In addition to highlighting other dynamic processes that are impacted in peripheral neuropathies, we focus on impaired mitochondrial quality control as a potential unifying theme for why mitochondrial dysfunction and impairments in mitochondrial dynamics in particular cause peripheral neuropathy.
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Affiliation(s)
- Govinda Sharma
- Departments of Medical Genetics and Biochemistry & Molecular Biology, Cumming School of Medicine, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada;
| | - Gerald Pfeffer
- Departments of Clinical Neurosciences and Medical Genetics, Cumming School of Medicine, Hotchkiss Brain Institute, Alberta Child Health Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada;
| | - Timothy E. Shutt
- Departments of Medical Genetics and Biochemistry & Molecular Biology, Cumming School of Medicine, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada;
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