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Wu YT, Huang SC, Shiao YM, Syu WC, Wei YH, Hsu YC. Identification of new variants in MTRNR1 and MTRNR2 genes using whole mitochondrial genome sequencing in a Taiwanese family with MERRF (myoclonic epilepsy with ragged-red fibers) syndrome. Hear Res 2023; 438:108876. [PMID: 37683310 DOI: 10.1016/j.heares.2023.108876] [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: 04/01/2022] [Revised: 07/30/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023]
Abstract
Mitochondrial encephalomyopathy is a multi-system disorder mostly caused by inborn errors of the oxidative phosphorylation (OXPHOS) system and usually manifested as complex neurological disorder and muscle weakness. Myoclonic epilepsy with ragged-red fibers (MERRF) syndrome is one of the major subtypes of mitochondrial disease associated with the m.8344A>G mutation in mitochondrial tRNALys gene. In addition to the symptoms in central nervous and muscle systems, a portion of the patients may develop hearing loss, which has been linked to the genetic mutations of mitochondrial DNA (mtDNA) especially in the mitochondrial ribosome RNA (rRNA) gene. Despite a great number of studies focusing on the consequences of mtDNA mutations, the mechanism of pathogenesis of these overt diseases has remained unclear, and there is no specific and effective treatment for MERRF syndromes. In this study, we developed a high-quality mtDNA sequencing method by next generation sequencing technology to search for the additional pathogenic variations of mtDNA from skin fibroblasts of four members in a Taiwanese family with MERRF syndrome. Through uncovering the signatures of all mtDNA variants in the MERRF family, we identified novel mtDNA variants in the genes encoding mitochondrial 12S and 16S rRNAs. The finding from this study will give us further insight into the molecular mechanisms driving the phenotypic variability and timing of onset of the MERRF syndrome.
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Affiliation(s)
- Yu-Ting Wu
- Center for Mitochondrial Medicine and Free Radical Research, Changhua Christian Hospital, Changhua City 50046, Taiwan
| | | | | | - Wei-Chi Syu
- Union Clinical Laboratory, Taipei 10665, Taiwan
| | - Yau-Huei Wei
- Center for Mitochondrial Medicine and Free Radical Research, Changhua Christian Hospital, Changhua City 50046, Taiwan
| | - Yi-Chao Hsu
- Department of Audiology and Speech-Language Pathology, Mackay Medical College, New Taipei City 25245, Taiwan; Institute of Biomedical Sciences, Mackay Medical College, New Taipei City 25245, Taiwan
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Wu YT, Tay HY, Yang JT, Liao HH, Ma YS, Wei YH. Mitochondrial impairment and synaptic dysfunction are associated with neurological defects in iPSCs-derived cortical neurons of MERRF patients. J Biomed Sci 2023; 30:70. [PMID: 37605213 PMCID: PMC10441704 DOI: 10.1186/s12929-023-00966-8] [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: 04/25/2023] [Accepted: 08/08/2023] [Indexed: 08/23/2023] Open
Abstract
BACKGROUND Myoclonic epilepsy with ragged-red fibers (MERRF) syndrome is a rare inherited mitochondrial disease mainly caused by the m.8344A > G mutation in mitochondrial tRNALys gene, and usually manifested as complex neurological disorders and muscle weakness. Currently, the pathogenic mechanism of this disease has not yet been resolved, and there is no effective therapy for MERRF syndrome. In this study, MERRF patients-derived iPSCs were used to model patient-specific neurons for investigation of the pathogenic mechanism of neurological disorders in mitochondrial disease. METHODS MERRF patient-derived iPSCs were differentiated into excitatory glutamatergic neurons to unravel the effects of the m.8344A > G mutation on mitochondrial bioenergetic function, neural-lineage differentiation and neuronal function. By the well-established differentiation protocol and electrophysiological activity assay platform, we examined the pathophysiological behaviors in cortical neurons of MERRF patients. RESULTS We have successfully established the iPSCs-derived neural progenitor cells and cortical-like neurons of patients with MERRF syndrome that retained the heteroplasmy of the m.8344A > G mutation from the patients' skin fibroblasts and exhibited the phenotype of the mitochondrial disease. MERRF neural cells harboring the m.8344A > G mutation exhibited impaired mitochondrial bioenergetic function, elevated ROS levels and imbalanced expression of antioxidant enzymes. Our findings indicate that neural immaturity and synaptic protein loss led to the impairment of neuronal activity and plasticity in MERRF neurons harboring the m.8344A > G mutation. By electrophysiological recordings, we monitored the in vivo neuronal behaviors of MERRF neurons and found that neurons harboring a high level of the m.8344A > G mutation exhibited impairment of the spontaneous and evoked potential-stimulated neuronal activities. CONCLUSIONS We demonstrated for the first time the link of mitochondrial impairment and synaptic dysfunction to neurological defects through impeding synaptic plasticity in excitatory neurons derived from iPSCs of MERRF patients harboring the m.8344A > G mutation. This study has provided new insight into the pathogenic mechanism of the tRNALys gene mutation of mtDNA, which is useful for the development of a patient-specific iPSCs platform for disease modeling and screening of new drugs to treat patients with MERRF syndrome.
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Affiliation(s)
- Yu-Ting Wu
- Center for Mitochondrial Medicine and Free Radical Research, Changhua Christian Hospital, Changhua City, Taiwan, 50046
| | - Hui-Yi Tay
- Center for Mitochondrial Medicine and Free Radical Research, Changhua Christian Hospital, Changhua City, Taiwan, 50046
| | - Jung-Tse Yang
- Center for Mitochondrial Medicine and Free Radical Research, Changhua Christian Hospital, Changhua City, Taiwan, 50046
| | - Hsiao-Hui Liao
- Center for Mitochondrial Medicine and Free Radical Research, Changhua Christian Hospital, Changhua City, Taiwan, 50046
| | - Yi-Shing Ma
- Center for Mitochondrial Medicine and Free Radical Research, Changhua Christian Hospital, Changhua City, Taiwan, 50046
| | - Yau-Huei Wei
- Center for Mitochondrial Medicine and Free Radical Research, Changhua Christian Hospital, Changhua City, Taiwan, 50046.
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, 112.
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Gonçalves FG, Alves CAPF, Heuer B, Peterson J, Viaene AN, Reis Teixeira S, Martín-Saavedra JS, Andronikou S, Goldstein A, Vossough A. Primary Mitochondrial Disorders of the Pediatric Central Nervous System: Neuroimaging Findings. Radiographics 2021; 40:2042-2067. [PMID: 33136487 DOI: 10.1148/rg.2020200052] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Primary mitochondrial disorders (PMDs) constitute the most common cause of inborn errors of metabolism in children, and they frequently affect the central nervous system. Neuroimaging findings of PMDs are variable, ranging from unremarkable and nonspecific to florid and highly suggestive. An overview of PMDs, including a synopsis of the basic genetic concepts, main clinical symptoms, and neuropathologic features, is presented. In addition, eight of the most common PMDs that have a characteristic imaging phenotype in children are reviewed in detail. Online supplemental material is available for this article. ©RSNA, 2020.
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Affiliation(s)
- Fabrício Guimarães Gonçalves
- From the Department of Radiology, Division of Neuroradiology (F.G.G., C.A.P.F.A., S.R.T., J.S.M.S., S.A., A.V.), Department of Pathology (A.N.V.), and Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics (B.H., J.P., A.G.), Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104-4399; and Departments of Pediatrics (A.G.) and Radiology (S.A., A.V.), University of Pennsylvania Perelman School of Medicine (A.N.V.), Philadelphia, Pa
| | - César Augusto Pinheiro Ferreira Alves
- From the Department of Radiology, Division of Neuroradiology (F.G.G., C.A.P.F.A., S.R.T., J.S.M.S., S.A., A.V.), Department of Pathology (A.N.V.), and Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics (B.H., J.P., A.G.), Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104-4399; and Departments of Pediatrics (A.G.) and Radiology (S.A., A.V.), University of Pennsylvania Perelman School of Medicine (A.N.V.), Philadelphia, Pa
| | - Beth Heuer
- From the Department of Radiology, Division of Neuroradiology (F.G.G., C.A.P.F.A., S.R.T., J.S.M.S., S.A., A.V.), Department of Pathology (A.N.V.), and Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics (B.H., J.P., A.G.), Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104-4399; and Departments of Pediatrics (A.G.) and Radiology (S.A., A.V.), University of Pennsylvania Perelman School of Medicine (A.N.V.), Philadelphia, Pa
| | - James Peterson
- From the Department of Radiology, Division of Neuroradiology (F.G.G., C.A.P.F.A., S.R.T., J.S.M.S., S.A., A.V.), Department of Pathology (A.N.V.), and Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics (B.H., J.P., A.G.), Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104-4399; and Departments of Pediatrics (A.G.) and Radiology (S.A., A.V.), University of Pennsylvania Perelman School of Medicine (A.N.V.), Philadelphia, Pa
| | - Angela N Viaene
- From the Department of Radiology, Division of Neuroradiology (F.G.G., C.A.P.F.A., S.R.T., J.S.M.S., S.A., A.V.), Department of Pathology (A.N.V.), and Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics (B.H., J.P., A.G.), Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104-4399; and Departments of Pediatrics (A.G.) and Radiology (S.A., A.V.), University of Pennsylvania Perelman School of Medicine (A.N.V.), Philadelphia, Pa
| | - Sara Reis Teixeira
- From the Department of Radiology, Division of Neuroradiology (F.G.G., C.A.P.F.A., S.R.T., J.S.M.S., S.A., A.V.), Department of Pathology (A.N.V.), and Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics (B.H., J.P., A.G.), Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104-4399; and Departments of Pediatrics (A.G.) and Radiology (S.A., A.V.), University of Pennsylvania Perelman School of Medicine (A.N.V.), Philadelphia, Pa
| | - Juan Sebastián Martín-Saavedra
- From the Department of Radiology, Division of Neuroradiology (F.G.G., C.A.P.F.A., S.R.T., J.S.M.S., S.A., A.V.), Department of Pathology (A.N.V.), and Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics (B.H., J.P., A.G.), Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104-4399; and Departments of Pediatrics (A.G.) and Radiology (S.A., A.V.), University of Pennsylvania Perelman School of Medicine (A.N.V.), Philadelphia, Pa
| | - Savvas Andronikou
- From the Department of Radiology, Division of Neuroradiology (F.G.G., C.A.P.F.A., S.R.T., J.S.M.S., S.A., A.V.), Department of Pathology (A.N.V.), and Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics (B.H., J.P., A.G.), Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104-4399; and Departments of Pediatrics (A.G.) and Radiology (S.A., A.V.), University of Pennsylvania Perelman School of Medicine (A.N.V.), Philadelphia, Pa
| | - Amy Goldstein
- From the Department of Radiology, Division of Neuroradiology (F.G.G., C.A.P.F.A., S.R.T., J.S.M.S., S.A., A.V.), Department of Pathology (A.N.V.), and Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics (B.H., J.P., A.G.), Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104-4399; and Departments of Pediatrics (A.G.) and Radiology (S.A., A.V.), University of Pennsylvania Perelman School of Medicine (A.N.V.), Philadelphia, Pa
| | - Arastoo Vossough
- From the Department of Radiology, Division of Neuroradiology (F.G.G., C.A.P.F.A., S.R.T., J.S.M.S., S.A., A.V.), Department of Pathology (A.N.V.), and Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics (B.H., J.P., A.G.), Children's Hospital of Philadelphia, 3401 Civic Center Blvd, Philadelphia, PA 19104-4399; and Departments of Pediatrics (A.G.) and Radiology (S.A., A.V.), University of Pennsylvania Perelman School of Medicine (A.N.V.), Philadelphia, Pa
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Bazhin AA, Chambon M, Vesin J, Bortoli J, Collins JW, Turcatti G, Chou CJ, Goun EA. A Universal Assay for Aminopeptidase Activity and Its Application for Dipeptidyl Peptidase-4 Drug Discovery. Anal Chem 2018; 91:1098-1104. [PMID: 30511572 DOI: 10.1021/acs.analchem.8b04672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Aminopeptidases, such as dipeptidyl peptidase-4 (DPP-4, CD26), are potent therapeutic targets for pharmacological interventions because they play key roles in many important pathological pathways. To analyze aminopeptidase activity in vitro (including high-throughput screening [HTS]), in vivo, and ex vivo, we developed a highly sensitive and quantitative bioluminescence-based readout method. We successfully applied this method to screening drugs with potential DPP-4 inhibitory activity. Using this method, we found that cancer drug mitoxantrone possesses significant DPP-4 inhibitory activity both in vitro and in vivo. The pharmacophore of mitoxantrone was further investigated by testing a variety of its structural analogues.
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Affiliation(s)
| | | | | | | | | | | | - Chieh Jason Chou
- Microbiome and Metabolism , Nestlé Institute of Health Sciences SA , Lausanne 1015 , Switzerland
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5
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Pinto WBVR, Souza PVS, Oliveira ASB. Prognostication in MELAS syndrome and other m.3243A-G mutation-associated disorders. Eur J Neurol 2016; 24:231-232. [DOI: 10.1111/ene.13211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- W. B. V. R. Pinto
- Division of Neuromuscular Diseases; Department of Neurology and Neurosurgery; Federal University of São Paulo (UNIFESP); São Paulo SP Brazil
| | - P. V. S. Souza
- Division of Neuromuscular Diseases; Department of Neurology and Neurosurgery; Federal University of São Paulo (UNIFESP); São Paulo SP Brazil
| | - A. S. B. Oliveira
- Division of Neuromuscular Diseases; Department of Neurology and Neurosurgery; Federal University of São Paulo (UNIFESP); São Paulo SP Brazil
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Fayssoil A, Laforêt P, Bougouin W, Jardel C, Lombès A, Bécane HM, Berber N, Stojkovic T, Béhin A, Eymard B, Duboc D, Wahbi K. Prediction of long-term prognosis by heteroplasmy levels of the m.3243A>G mutation in patients with the mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes syndrome. Eur J Neurol 2016; 24:255-261. [PMID: 27869334 DOI: 10.1111/ene.13176] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 09/16/2016] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND PURPOSE Our aim was to determine the prognostic value of urine and blood heteroplasmy in patients with the m.3243A>G mutation. METHODS Adults with the m.3243A>G mutation referred to our institution between January 2000 and May 2014 were retrospectively included. The relationship between their baseline clinical characteristics, their mutation load in urine and blood, and major adverse events (MAEs) during follow-up, defined as medical complications requiring a hospitalization or complicated by death, was studied. RESULTS Of the 43 patients (age 45.6 ± 13.3 years) included in the study, 36 patients were symptomatic, including nine with evidence of focal brain involvement, and seven were asymptomatic. Over a 5.5 ± 4.0 year mean follow-up duration, 14 patients (33%) developed MAEs. Patients with MAEs had a higher mutation load than others in urine (60.1% ± 13.8% vs. 40.6% ± 26.2%, P = 0.01) and in blood (26.9% ± 18.4% vs. 16.0% ± 12.1%, P = 0.03). Optimal cutoff values for the prediction of MAEs were 45% for urine and 35% for blood. In multivariate analysis, mutation load in urine ≥45% [odds ratio 25.3; 95% confidence interval (CI) 1.1-567.8; P = 0.04], left ventricular hypertrophy (odds ratio 16.7; 95% CI 1.3- 222.5; P = 0.03) and seizures (odds ratio 48.3; 95% CI 2.5-933; P = 0.01) were associated with MAEs. CONCLUSIONS Patients with the m.3243A>G mutation are at high risk of MAEs, which can be independently predicted by mutation load in urine ≥45%, a personal history of seizures, and left ventricular hypertrophy.
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Affiliation(s)
- A Fayssoil
- AP-HP, Pitié-Salpêtrière Hospital, Reference Centre for Muscle Diseases Paris-Est, Myology Institute, Paris, France.,AP-HP, Raymond Poincaré Hospital, Versailles Saint-Quentin en Yvelines University, Garches, France
| | - P Laforêt
- AP-HP, Pitié-Salpêtrière Hospital, Reference Centre for Muscle Diseases Paris-Est, Myology Institute, Paris, France.,Myology Institute, Pitié-Salpêtrière Hospital, Pierre et Marie Curie Paris 6 University, Paris, France
| | - W Bougouin
- INSERM Unit 970, Paris Cardiovascular Research Centre (PARCC), Paris, France.,Paris-Descartes, Sorbonne Paris Cité University, Paris, France.,Medical Intensive Care Unit, AP-HP, Cochin Hospital, Paris, France
| | - C Jardel
- Biochemistry Department, AP-HP, Pitié-Salpêtrière Hospital, Paris, France.,INSERM U1016, CNRS UMR 8104, Institut Cochin, Paris, France
| | - A Lombès
- Paris-Descartes, Sorbonne Paris Cité University, Paris, France.,INSERM U1016, CNRS UMR 8104, Institut Cochin, Paris, France
| | - H M Bécane
- AP-HP, Pitié-Salpêtrière Hospital, Reference Centre for Muscle Diseases Paris-Est, Myology Institute, Paris, France
| | - N Berber
- AP-HP, Pitié-Salpêtrière Hospital, Reference Centre for Muscle Diseases Paris-Est, Myology Institute, Paris, France
| | - T Stojkovic
- AP-HP, Pitié-Salpêtrière Hospital, Reference Centre for Muscle Diseases Paris-Est, Myology Institute, Paris, France
| | - A Béhin
- AP-HP, Pitié-Salpêtrière Hospital, Reference Centre for Muscle Diseases Paris-Est, Myology Institute, Paris, France
| | - B Eymard
- AP-HP, Pitié-Salpêtrière Hospital, Reference Centre for Muscle Diseases Paris-Est, Myology Institute, Paris, France.,Myology Institute, Pitié-Salpêtrière Hospital, Pierre et Marie Curie Paris 6 University, Paris, France
| | - D Duboc
- AP-HP, Pitié-Salpêtrière Hospital, Reference Centre for Muscle Diseases Paris-Est, Myology Institute, Paris, France.,Paris-Descartes, Sorbonne Paris Cité University, Paris, France.,Department of Cardiology, AP-HP, Cochin Hospital, Paris Descartes University, Paris, France
| | - K Wahbi
- AP-HP, Pitié-Salpêtrière Hospital, Reference Centre for Muscle Diseases Paris-Est, Myology Institute, Paris, France.,Paris-Descartes, Sorbonne Paris Cité University, Paris, France.,Department of Cardiology, AP-HP, Cochin Hospital, Paris Descartes University, Paris, France
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7
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Causes of Death in Adults with Mitochondrial Disease. JIMD Rep 2015; 26:103-13. [PMID: 26354038 DOI: 10.1007/8904_2015_449] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 04/23/2015] [Accepted: 04/27/2015] [Indexed: 12/04/2022] Open
Abstract
INTRODUCTION Mitochondrial diseases are a clinically, biochemically and genetically heterogeneous group of disorders with a variable age of onset and rate of disease progression. It might therefore be expected that this variation be reflected in the age and cause of death. However, to date, little has been reported regarding the 'end-of-life' period and causes of death in mitochondrial disease patients. For some specific syndromes, the associated clinical problems might predict the cause of death, but for many patients, it remains difficult to provide an accurate prognosis. AIMS To describe a retrospective cohort of adult mitochondrial disease patients who had attended the NHS Highly Specialised Services for Rare Mitochondrial Diseases in Newcastle upon Tyne (UK), evaluate life expectancy and causes of death and assess the consequences for daily patient care. METHODS All deceased adult patients cared for at this centre over a period of 10 years were included in the study. Patient history, data on laboratory findings, biochemical investigations and genetic studies were analysed retrospectively. RESULTS A total of 30 adult mitochondrial patients died within the time period of the study. The main mitochondrial disease-related causes of death in this patient cohort were respiratory failure, cardiac failure and acute cerebral incidents such as seizures and strokes. In almost half of the patients, the cause of death remained unknown. Based on our study, we present recommendations regarding the care of patients with mitochondrial disease.
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Liu CH, Chang CH, Kuo HC, Ro LS, Liou CW, Wei YH, Huang CC. Prognosis of symptomatic patients with the A3243G mutation of mitochondrial DNA. J Formos Med Assoc 2012; 111:489-94. [PMID: 23021505 DOI: 10.1016/j.jfma.2011.06.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 06/17/2011] [Accepted: 06/25/2011] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND/PURPOSE The clinical analyses and prognoses of mitochondrial diseases with A3243G mutation are rarely documented in Taiwan. Our study investigated the clinical phenotypes and the outcomes of patients with mitochondrial disease and the A3243G mutation of mtDNA in a Taiwanese population, and compared these with previous reports. METHODS We retrospectively studied 22 consecutive patients with mitochondrial disease and the A3243G mutation of mtDNA in Chang Gung Memorial Hospital between 1988 and 2009. All patients underwent a detailed demographic registration, neurological examinations, a muscle biopsy, and mitochondrial DNA analysis. Modified Rankin scale, the presence of recurrent strokes or seizures, critical medical complications, and death were monitored during the follow-up period. RESULTS Of the 22 patients, seizures and stroke-like episodes were found in 12 (55%). Visceral involvement, including cardiomyopathy, nephropathy, and pulmonary hypertension, were noted in five patients (23%). Patients with seizures had a high frequency of status epilepticus (92%) and a younger age of onset (21.3±7.2 years). Both the Kaplan-Meier survival analysis and the Cox-regression model showed a marked deterioration in patients with seizures after 7 years of follow-up. CONCLUSION Our study found that seizures and status epilepticus are the most important predictive values for a poor outcome in patients with the mtA3243G mutation of mtDNA. Age of onset and visceral organ involvement had no prominent influence on the prognosis. Some medical complications could be well controlled or even reversed after management.
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Affiliation(s)
- Chi-Hung Liu
- Department of Neurology, Chang Gung Memorial Hospital, Linkou branch, Taoyuan, Taiwan
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9
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AMPK-mediated increase of glycolysis as an adaptive response to oxidative stress in human cells: Implication of the cell survival in mitochondrial diseases. Biochim Biophys Acta Mol Basis Dis 2012; 1822:233-47. [DOI: 10.1016/j.bbadis.2011.09.014] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 09/21/2011] [Accepted: 09/23/2011] [Indexed: 11/22/2022]
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10
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Saracchi E, Tremolizzo L, DiFrancesco JC, Brighina L, Costantino G, Frigeni B, Brioschi M, Piatti ML, Fumagalli L, Marzorati L, Curtò NA, Ferrarese C. Cerebellar hematoma in a carrier of the A3243G MELAS mutation. Neurol Sci 2011; 32:365-6. [PMID: 21327397 DOI: 10.1007/s10072-011-0493-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 02/03/2011] [Indexed: 11/29/2022]
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11
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Pilch J, Asman M, Jamroz E, Kajor M, Kotrys-Puchalska E, Goss M, Krzak M, Witecka J, Gmiński J, Sieroń AL. Surveyor nuclease detection of mutations and polymorphisms of mtDNA in children. Pediatr Neurol 2010; 43:325-30. [PMID: 20933175 DOI: 10.1016/j.pediatrneurol.2010.05.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2009] [Revised: 01/27/2010] [Accepted: 05/26/2010] [Indexed: 10/19/2022]
Abstract
Mitochondrial encephalomyopathies are complex disorders with wide range of clinical manifestations. Particularly time-consuming is the identification of mutations in mitochondrial DNA. A group of 20 children with clinical manifestations of mitochondrial encephalomyopathies was selected for molecular studies. The aims were (a) to identify mutations in mtDNA isolated from muscle and (b) to verify detected mutations in DNA isolated from blood, in order to assess the utility of a Surveyor nuclease assay kit for patient screening. The most common changes found were polymorphisms, including a few missense mutations altering the amino acid sequence of mitochondrial proteins. In two boys with MELAS (i.e., mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes), a mutation A→G3243 was detected in the tRNALeu gene of mtDNA isolated from muscle and blood. In one boy, the carrier status of his mother was confirmed, based on molecular analysis of DNA isolated from blood. A method using Surveyor nuclease allows systematic screening for small mutations in mtDNA, using as its source blood of the patients and asymptomatic carriers. The method still requires confirmation studying a larger group. In some patients, the use of this method should precede and might limit indications for traumatic muscle and skin biopsy.
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Affiliation(s)
- Jacek Pilch
- Department of Child Neurology, Medical University of Silesia, ul. Medyków 16, Katowice, Poland.
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12
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Brinckmann A, Weiss C, Wilbert F, von Moers A, Zwirner A, Stoltenburg-Didinger G, Wilichowski E, Schuelke M. Regionalized pathology correlates with augmentation of mtDNA copy numbers in a patient with myoclonic epilepsy with ragged-red fibers (MERRF-syndrome). PLoS One 2010; 5:e13513. [PMID: 20976001 PMCID: PMC2958123 DOI: 10.1371/journal.pone.0013513] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 09/29/2010] [Indexed: 11/18/2022] Open
Abstract
Human patients with myoclonic epilepsy with ragged-red fibers (MERRF) suffer from regionalized pathology caused by a mutation in the mitochondrial DNA (m.8344A→G). In MERRF-syndrome brain and skeletal muscles are predominantly affected, despite mtDNA being present in any tissue. In the past such tissue-specificity could not be explained by varying mtDNA mutation loads. In search for a region-specific pathology in human individuals we determined the mtDNA/nDNA ratios along with the mutation loads in 43 different post mortem tissue samples of a 16-year-old female MERRF patient and in four previously healthy victims of motor vehicle accidents. In brain and muscle we further determined the quantity of mitochondrial proteins (COX subunits II and IV), transcription factors (NRF1 and TFAM), and VDAC1 (Porin) as a marker for the mitochondrial mass. In the patient the mutation loads varied merely between 89-100%. However, mtDNA copy numbers were increased 3-7 fold in predominantly affected brain areas (e.g. hippocampus, cortex and putamen) and in skeletal muscle. Similar increases were absent in unaffected tissues (e.g. heart, lung, kidney, liver, and gastrointestinal organs). Such mtDNA copy number increase was not paralleled by an augmentation of mitochondrial mass in some investigated tissues, predominantly in the most affected tissue regions of the brain. We thus conclude that "futile" stimulation of mtDNA replication per se or a secondary failure to increase the mitochondrial mass may contribute to the regionalized pathology seen in MERRF-syndrome.
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Affiliation(s)
- Anja Brinckmann
- Department of Neuropediatrics, Charité University Medical School, Berlin, Germany
| | - Claudia Weiss
- Department of Neuropediatrics, Charité University Medical School, Berlin, Germany
| | - Friederike Wilbert
- Department of Neuropediatrics, Charité University Medical School, Berlin, Germany
- NeuroCure Clinical Research Center, Charité University Medical School, Berlin, Germany
| | | | - Angelika Zwirner
- Department of Neuropediatrics, Charité University Medical School, Berlin, Germany
| | | | - Ekkehard Wilichowski
- Department of Pediatrics and Pediatric Neurology, Georg August University, Göttingen, Germany
| | - Markus Schuelke
- Department of Neuropediatrics, Charité University Medical School, Berlin, Germany
- NeuroCure Clinical Research Center, Charité University Medical School, Berlin, Germany
- * E-mail:
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13
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The uncommon causes of status epilepticus: a systematic review. Epilepsy Res 2010; 91:111-22. [PMID: 20709500 DOI: 10.1016/j.eplepsyres.2010.07.015] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Revised: 07/14/2010] [Accepted: 07/18/2010] [Indexed: 01/01/2023]
Abstract
This paper reports the first systematic review of uncommon causes of status epilepticus reported in the literature between 1990 and 2008. Uncommon causes are defined as those not listed in the main epidemiological studies of status epilepticus. 181 causes were identified. These were easily categorised into 5 specific aetiological categories: immunological disorders, mitochondrial disorders, infectious diseases, genetic disorders and drugs/toxins. A sixth category of 'other causes' has also been included. Knowledge of these causes is important for clinical management and treatment, and also for a better understanding of the pathophysiology of status epilepticus.
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14
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Ju Seok Ryu, Sook Joung Lee, In Young Sung, Tae Sung Ko, Han Ik Yoo. Depressive episode with catatonic features in a case of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). J Child Neurol 2009; 24:1307-9. [PMID: 19451268 DOI: 10.1177/0883073809334380] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Three months previously, a 17-year-old girl had complained of right-hand side hemiparesis, and her brain magnetic resonance imaging (MRI) showed a signal change in the left temporoparietooccipital area. The 3243A>G mutation was found in mitochondrial DNA. She was diagnosed with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and was prescribed dichloroacetic acid to treat lactic acidosis. Her health improved. Two months later, she developed drowsiness and generalized weakness. A New lesion was not found on brain MRI, and electrodiagnostic findings were compatible with acute motor sensory axonal neuropathy. Her negative symptoms, such as depressed mood, loss of interest in activities, psychomotor retardation, and hypersomnia, were aggravated. She was prescribed antidepressants and psychostimulants by a psychiatrist after diagnosis of severe depression episode with catatonic features. One month later, her catatonic condition had improved with medication. Our experience shows that psychiatric diagnostic evaluation of abruptly regressed neurologic and clinical features is important, even in a patient with devastating underlying disease.
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Affiliation(s)
- Ju Seok Ryu
- Department of Rehabilitation Medicine, University of Ulsan College of Medicine, Seoul, Korea
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15
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Erol I, Alehan F, Horvath R, Schneiderat P, Talim B. Demyelinating disease of central and peripheral nervous systems associated with a A8344G mutation in tRNALys. Neuromuscul Disord 2009; 19:275-8. [DOI: 10.1016/j.nmd.2009.01.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 11/28/2008] [Accepted: 01/22/2009] [Indexed: 11/26/2022]
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16
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Ito S, Shirai W, Asahina M, Hattori T. Clinical and brain MR imaging features focusing on the brain stem and cerebellum in patients with myoclonic epilepsy with ragged-red fibers due to mitochondrial A8344G mutation. AJNR Am J Neuroradiol 2007; 29:392-5. [PMID: 17989367 DOI: 10.3174/ajnr.a0865] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARY We report 3 patients with myoclonic epilepsy with ragged-red fibers (MERRF) diagnosed by mitochondrial A8344G mutation. Cerebellar ataxia was the first symptom in all patients. Conventional brain MR imaging showed atrophy of the superior cerebellar peduncles and the cerebellum in all patients and brain stem atrophy in 2 patients. In diffusion tensor analysis, fractional anisotropy of the superior cerebellar peduncles was mildly decreased in 1 patient. There was a discrepancy between clinical disabilities (severe) and radiologic abnormalities (mild). This discrepancy and atrophy of the superior cerebellar peduncles and the cerebellum may be important findings suggesting a diagnosis of MERRF.
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Affiliation(s)
- S Ito
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan.
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17
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Adhihetty PJ, Taivassalo T, Haller RG, Walkinshaw DR, Hood DA. The effect of training on the expression of mitochondrial biogenesis- and apoptosis-related proteins in skeletal muscle of patients with mtDNA defects. Am J Physiol Endocrinol Metab 2007; 293:E672-80. [PMID: 17551003 DOI: 10.1152/ajpendo.00043.2007] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondrial myopathy patients (MMPs) have impaired oxidative phosphorylation and exercise intolerance. Endurance training of MMPs improves exercise tolerance, but also increases mutational load. To assess the regulation of mitochondrial content in MMPs, we measured proteins involved in 1) biogenesis, 2) oxidative stress, and 3) apoptosis in MMPs and healthy controls (HCs) both before and after endurance training. Before training, MMPs had a greater mitochondrial content, along with a 1.4-fold (P < 0.05) higher expression of the biogenesis regulator peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha). The DNA repair enzyme 8-oxoguanine DNA glycolase-1 (OGG-1), the antioxidant manganese superoxide dismutase (MnSOD), and the apoptotic proteins AIF and Bcl-2 were higher in MMPs compared with HCs. Aconitase, an enzyme sensitive to oxidative stress, was 52% lower (P < 0.05) in MMPs when calculated based on an estimate of mitochondrial volume and oxidative stress-induced protein modifications tended to be higher in MMPs compared with HCs. Endurance training (ET) induced increases in mitochondrial content in both HC subjects and MMPs, but there was no effect of training on the regulatory proteins Tfam or PGC-1alpha. In MMPs, training induced a selective reduction of OGG-1, an increase in MnSOD, and a reduction in aconitase activity. Thus, before training, MMPs exhibited an adaptive response of nuclear proteins indicative of a compensatory increase in mitochondrial content. Following training, several parallel adaptations occurred in MMPs and HCs, which may contribute to previously observed functional improvements of exercise in MMPs. However, our results indicate that muscle from MMPs may be exposed to greater levels of oxidative stress during the course of training. Further investigation is required to evaluate the long-term benefits of endurance training as a therapeutic intervention for mitochondrial myopathy patients.
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Affiliation(s)
- Peter J Adhihetty
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada M3J 1P3
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18
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van de Glind G, de Vries M, Rodenburg R, Hol F, Smeitink J, Morava E. Resting muscle pain as the first clinical symptom in children carrying the MTTK A8344G mutation. Eur J Paediatr Neurol 2007; 11:243-6. [PMID: 17293137 DOI: 10.1016/j.ejpn.2007.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Revised: 01/04/2007] [Accepted: 01/05/2007] [Indexed: 11/28/2022]
Abstract
The characteristic clinical presentation, especially the appearance of muscle symptoms, is quite unique in children carrying the mtA8344G mutation. The diagnosis of MERRF syndrome is seldom made in the pediatric age. Fatigue is a common finding in children of pubertal age. Fatigue in combination with recurrent resting muscle pain occurs frequently in the initial phase of various hereditary muscle disorders and in several autoimmune, endocrine and metabolic syndromes. In the absence of obvious biochemical/metabolic abnormalities and in the lack of neurological symptoms the complaints are frequently labelled as fibromyalgia or chronic fatigue syndrome. In patients with behavioural or psychiatric abnormalities one might even start to question the organic etiology of the complaints. We describe a family carrying the classic MTTK mutation with a variable degree of heteroplasmy, presenting in childhood as isolated recurrent muscle pain as the first symptom of the disease.
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Affiliation(s)
- Gretha van de Glind
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
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19
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Finsterer J. Genetic, pathogenetic, and phenotypic implications of the mitochondrial A3243G tRNALeu(UUR) mutation. Acta Neurol Scand 2007; 116:1-14. [PMID: 17587249 DOI: 10.1111/j.1600-0404.2007.00836.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Mitochondrial disorders are frequently caused by mutations in mitochondrial genes and usually present as multisystem disease. One of the most frequent mitochondrial mutations is the A3,243G transition in the tRNALeu(UUR) gene. The phenotypic expression of the mutation is variable and comprises syndromic or non-syndromic mitochondrial disorders. Among the syndromic manifestations the mitochondrial encephalopathy, lactacidosis, and stroke-like episode (MELAS) syndrome is the most frequent. In single cases the A3,243G mutation may be associated with maternally inherited diabetes and deafness syndrome, myoclonic epilepsy and ragged-red fibers (MERRF) syndrome, MELAS/MERRF overlap syndrome, maternally inherited Leigh syndrome, chronic external ophthalmoplegia, or Kearns-Sayre syndrome. The wide phenotypic variability of the mutation is explained by the peculiarities of the mitochondrial DNA, such as heteroplasmy and mitotic segregation, resulting in different mutation loads in different tissues and family members. Moreover, there is some evidence that additional mtDNA sequence variations (polymorphisms, haplotypes) influence the phenotype of the A3,243G mutation. This review aims to give an overview on the actual knowledge about the genetic, pathogenetic, and phenotypic implications of the A3,243G mtDNA mutation.
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Affiliation(s)
- J Finsterer
- Krankenanstalt Rudolfstiftung, Vienna, Austria.
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20
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Oldfors A, Tulinius M. Mitochondrial encephalomyopathies. HANDBOOK OF CLINICAL NEUROLOGY 2007; 86:125-165. [PMID: 18808998 DOI: 10.1016/s0072-9752(07)86006-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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21
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Toivonen JM, Manjiry S, Touraille S, Alziari S, O'Dell KMC, Jacobs HT. Gene dosage and selective expression modify phenotype in a Drosophila model of human mitochondrial disease. Mitochondrion 2005; 3:83-96. [PMID: 16120347 DOI: 10.1016/s1567-7249(03)00077-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2003] [Revised: 06/03/2003] [Accepted: 06/04/2003] [Indexed: 11/22/2022]
Abstract
Human mitochondrial disease manifests with a wide range of clinical phenotypes of varying severity. To create a model for these disorders, we have manipulated the Drosophila gene technical knockout, encoding mitoribosomal protein S12. Various permutations of endogenous and transgenic alleles create a range of phenotypes, varying from larval developmental arrest through to mild neurological defects in the adult, and also mimic threshold effects associated with human mtDNA disease. Nuclear genetic background influences mutant phenotype by a compensatory mechanism affecting mitochondrial RNA levels. Selective expression of the wild-type allele indicates critical times and cell-types in development, in which mitochondrial protein synthesis deficiency leads to specific phenotypic outcomes.
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Affiliation(s)
- Janne M Toivonen
- Institute of Medical Technology and Tampere University Hospital, 33014 Tampere, Finland
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22
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Komlósi K, Kellermayer R, Maász A, Havasi V, Hollódy K, Vincze O, Merkli H, Pál E, Melegh B. Maternally inherited deafness and unusual phenotypic manifestations associated with A3243G mitochondrial DNA mutation. Pathol Oncol Res 2005; 11:82-6. [PMID: 15999151 DOI: 10.1007/bf02893371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Accepted: 05/15/2005] [Indexed: 11/30/2022]
Abstract
The mitochondrial DNA A3243G transition is a fairly common mutation which often associates with a MELAS (mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes) phenotype, however, a broad variety in the associated clinical picture has also been described. The patient reported here developed a generalized seizure at age 12, which was followed by bilateral hearing loss and occasional fatigue. The maternal inheritance pattern of hearing loss pointed to a possible mitochondrial origin, which was confirmed by molecular analysis of the mitochondrial DNA, revealing a heteroplasmic A3243G transition. Interestingly, muscle biopsy showed ragged-red fibers in the proband, which is unusual in the deafness-associated forms of this mitochondrial disorder. In addition to hearing impairment in four generations of the family, fatal cerebral embolization in the mother and fatal heart attack in the maternal grandmother (both at age 33) also occurred. On the contrary, diabetes, which usually accompanies the hearing loss variant, was specifically absent in all generations. The unusual manifestations associated with this mutation somewhat differentiate this family from the already known variants.
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Affiliation(s)
- Katalin Komlósi
- Department of Medical Genetics and Child Development, University of Pécs, Pécs, H-7624, Hungary
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23
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Biomedical vignette. J Biomed Sci 2002. [DOI: 10.1007/bf02254974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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