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Gao Y, Guo L, Wang F, Wang Y, Li P, Zhang D. Development of mitochondrial gene-editing strategies and their potential applications in mitochondrial hereditary diseases: a review. Cytotherapy 2024; 26:11-24. [PMID: 37930294 DOI: 10.1016/j.jcyt.2023.10.004] [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: 06/08/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 11/07/2023]
Abstract
Mitochondrial DNA (mtDNA) is a critical genome contained within the mitochondria of eukaryotic cells, with many copies present in each mitochondrion. Mutations in mtDNA often are inherited and can lead to severe health problems, including various inherited diseases and premature aging. The lack of efficient repair mechanisms and the susceptibility of mtDNA to damage exacerbate the threat to human health. Heteroplasmy, the presence of different mtDNA genotypes within a single cell, increases the complexity of these diseases and requires an effective editing method for correction. Recently, gene-editing techniques, including programmable nucleases such as restriction endonuclease, zinc finger nuclease, transcription activator-like effector nuclease, clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeats-associated 9 and base editors, have provided new tools for editing mtDNA in mammalian cells. Base editors are particularly promising because of their high efficiency and precision in correcting mtDNA mutations. In this review, we discuss the application of these techniques in mitochondrial gene editing and their limitations. We also explore the potential of base editors for mtDNA modification and discuss the opportunities and challenges associated with their application in mitochondrial gene editing. In conclusion, this review highlights the advancements, limitations and opportunities in current mitochondrial gene-editing technologies and approaches. Our insights aim to stimulate the development of new editing strategies that can ultimately alleviate the adverse effects of mitochondrial hereditary diseases.
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Affiliation(s)
- Yanyan Gao
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Linlin Guo
- The Affiliated Cardiovascular Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Fei Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Dejiu Zhang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
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Lopriore P, Ricciarini V, Siciliano G, Mancuso M, Montano V. Mitochondrial Ataxias: Molecular Classification and Clinical Heterogeneity. Neurol Int 2022; 14:337-356. [PMID: 35466209 PMCID: PMC9036286 DOI: 10.3390/neurolint14020028] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/26/2022] [Accepted: 03/28/2022] [Indexed: 01/25/2023] Open
Abstract
Ataxia is increasingly being recognized as a cardinal manifestation in primary mitochondrial diseases (PMDs) in both paediatric and adult patients. It can be caused by disruption of cerebellar nuclei or fibres, its connection with the brainstem, or spinal and peripheral lesions leading to proprioceptive loss. Despite mitochondrial ataxias having no specific defining features, they should be included in hereditary ataxias differential diagnosis, given the high prevalence of PMDs. This review focuses on the clinical and neuropathological features and genetic background of PMDs in which ataxia is a prominent manifestation.
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de Boer E, Ockeloen CW, Matalonga L, Horvath R, Rodenburg RJ, Coenen MJH, Janssen M, Henssen D, Gilissen C, Steyaert W, Paramonov I, Trimouille A, Kleefstra T, Verloes A, Vissers LELM. A MT-TL1 variant identified by whole exome sequencing in an individual with intellectual disability, epilepsy, and spastic tetraparesis. Eur J Hum Genet 2021; 29:1359-1368. [PMID: 34075211 PMCID: PMC8440635 DOI: 10.1038/s41431-021-00900-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 03/25/2021] [Accepted: 04/15/2021] [Indexed: 11/09/2022] Open
Abstract
The genetic etiology of intellectual disability remains elusive in almost half of all affected individuals. Within the Solve-RD consortium, systematic re-analysis of whole exome sequencing (WES) data from unresolved cases with (syndromic) intellectual disability (n = 1,472 probands) was performed. This re-analysis included variant calling of mitochondrial DNA (mtDNA) variants, although mtDNA is not specifically targeted in WES. We identified a functionally relevant mtDNA variant in MT-TL1 (NC_012920.1:m.3291T > C; NC_012920.1:n.62T > C), at a heteroplasmy level of 22% in whole blood, in a 23-year-old male with severe intellectual disability, epilepsy, episodic headaches with emesis, spastic tetraparesis, brain abnormalities, and feeding difficulties. Targeted validation in blood and urine supported pathogenicity, with heteroplasmy levels of 23% and 58% in index, and 4% and 17% in mother, respectively. Interestingly, not all phenotypic features observed in the index have been previously linked to this MT-TL1 variant, suggesting either broadening of the m.3291T > C-associated phenotype, or presence of a co-occurring disorder. Hence, our case highlights the importance of underappreciated mtDNA variants identifiable from WES data, especially for cases with atypical mitochondrial phenotypes and their relatives in the maternal line.
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Affiliation(s)
- Elke de Boer
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Charlotte W Ockeloen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Leslie Matalonga
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, John Van Geest Cambridge Centre for Brain Repair, Cambridge, UK
| | - Richard J Rodenburg
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marieke J H Coenen
- Department of Human Genetics, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mirian Janssen
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Dylan Henssen
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Wouter Steyaert
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ida Paramonov
- CNAG-CRG, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Aurélien Trimouille
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France
- MRGM, Maladies Rares: Génétique et Métabolisme, lNSERM U1211, Université de Bordeaux, Bordeaux, France
| | - Tjitske Kleefstra
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Alain Verloes
- Département de Génétique, APHP Robert DEBRE University Hospital and INSERM U1141, Paris, France
| | - Lisenka E L M Vissers
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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Hou Y, Zhao XT, Xie ZY, Yuan Y, Wang ZX. [Mitochondrial encephalopathy, lactic acidosis and stroke-like episodes / myoclonus epilepsy with ragged-red fibers /Leigh overlap syndrome caused by mitochondrial DNA 8344A>G mutation]. BEIJING DA XUE XUE BAO. YI XUE BAN = JOURNAL OF PEKING UNIVERSITY. HEALTH SCIENCES 2020. [PMID: 33047718 DOI: 10.19723/j.issn.1671-167x.2020.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Mitochondrial deoxyribonucleic acid (mtDNA) 8344 A>G (m.8344A>G) mutation is the common mutation associated with mitochondrial myoclonus epilepsy with ragged-red fibers (MERRF) syndrome. Herein we report a rare case with mitochondrial encephalopathy, lactic acidosis and stroke-like episodes/MERRF/Leigh (MELAS/MERRF/Leigh) overlap syndrome caused by m.8344A>G mutation. METHODS The clinical and imaging data of the patient were collected and an open muscle biopsy was carried out. We further employed molecular genetic analyses to detect mtDNA mutation in the proband and his mother. And then a clinical and neuroimaging follow-up was performed. RESULTS This patient was a 25-year-old male, who developed exercise intolerance since the age of 6. At age 10, he suffered from acute episodes of hemianopia, and cranial magnetic resonance imaging (MRI) showed occipital stroke-like lesions and cranial magnetic resonance spectroscopy (MRS) revealed a lactate peak corresponding to the lesion. After that the patient presented slowly progressive psychomotor decline. He had myoclonic seizures and cerebellar ataxia since the age of 12. At age 21, he was admitted to our hospital because of confusion and cranial MRI revealed symmetrical lesions in bilateral posterior putamen, thalami and midbrain. Then repeated MRI showed progression of original lesions and new frontal multiple stroke-like lesions. Symptomatic and rehabilitation treatment relieved his condition. Follow-up cranial MRI at age 24 showed the lesions in basal ganglia and thalami diminished, and the midbrain lesions even completely vanished. Muscle pathology indicated the presence of numerous scattered ragged-red fibers (RRF), suggestive of a mitochondrial disorder. Polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) detected the m.8344A>G mutation of the MT-TK gene encoding mitochondrial transfer RNA for lysine in the patient's blood. Next generation sequencing (NGS) of the whole mitochondrial genome identified that the proportion of m.8344A>G was 90%, and no other mtDNA mutation was detected. Sanger sequencing further identified this mutation both in the proband and his mother's blood, although the mutation load was much lower in his mother's blood with approximately 10% heteroplasmy. CONCLUSION The present study is the first to describe a patient with m.8344A>G mutation in association with the MELAS/MERRF/Leigh overlap syndrome, which expands the phenotypic spectrum of the m.8344A>G mutation.
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Mustafa MF, Fakurazi S, Abdullah MA, Maniam S. Pathogenic Mitochondria DNA Mutations: Current Detection Tools and Interventions. Genes (Basel) 2020; 11:genes11020192. [PMID: 32059522 PMCID: PMC7074468 DOI: 10.3390/genes11020192] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/10/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023] Open
Abstract
Mitochondria are best known for their role in energy production, and they are the only mammalian organelles that contain their own genomes. The mitochondrial genome mutation rate is reported to be 10–17 times higher compared to nuclear genomes as a result of oxidative damage caused by reactive oxygen species during oxidative phosphorylation. Pathogenic mitochondrial DNA mutations result in mitochondrial DNA disorders, which are among the most common inherited human diseases. Interventions of mitochondrial DNA disorders involve either the transfer of viable isolated mitochondria to recipient cells or genetically modifying the mitochondrial genome to improve therapeutic outcome. This review outlines the common mitochondrial DNA disorders and the key advances in the past decade necessary to improve the current knowledge on mitochondrial disease intervention. Although it is now 31 years since the first description of patients with pathogenic mitochondrial DNA was reported, the treatment for mitochondrial disease is often inadequate and mostly palliative. Advancements in diagnostic technology improved the molecular diagnosis of previously unresolved cases, and they provide new insight into the pathogenesis and genetic changes in mitochondrial DNA diseases.
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MESH Headings
- Acidosis, Lactic/congenital
- Acidosis, Lactic/genetics
- Acidosis, Lactic/metabolism
- DNA Mutational Analysis
- DNA, Mitochondrial/genetics
- DNA, Mitochondrial/metabolism
- Epilepsies, Myoclonic/congenital
- Epilepsies, Myoclonic/genetics
- Epilepsies, Myoclonic/therapy
- Gene Editing/methods
- Genetic Therapy/methods
- Humans
- Leigh Disease/genetics
- Leigh Disease/metabolism
- Leigh Disease/therapy
- Mitochondria/genetics
- Mitochondria/metabolism
- Mitochondria/pathology
- Mitochondrial Diseases/genetics
- Mitochondrial Diseases/metabolism
- Mitochondrial Diseases/therapy
- Mitochondrial Encephalomyopathies/congenital
- Mitochondrial Encephalomyopathies/genetics
- Mitochondrial Encephalomyopathies/metabolism
- Mutation
- Optic Atrophy, Hereditary, Leber/genetics
- Optic Atrophy, Hereditary, Leber/metabolism
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Affiliation(s)
- Mohd Fazirul Mustafa
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
| | - Sharida Fakurazi
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
| | - Maizaton Atmadini Abdullah
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
- Laboratory of Molecular Medicine, Institute of Bioscience, University Putra Malaysia, 43400 UPM Serdang Selangor Darul Ehsan, Malaysia
| | - Sandra Maniam
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
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Abstract
INTRODUCTION Epilepsy is a prominent feature of myoclonic epilepsy with ragged-red fibers (MERRF)-syndrome. The most frequent seizure type is myoclonic seizures, of which the treatment is challenging and empiric. AREAS COVERED Herein, the author summarises and discusses previous and recent findings of antiepileptic drug (AED) treatment in MERRF-syndrome. EXPERT OPINION MERRF-syndrome is a predominantly maternally inherited, multisystem mitochondrial disorder caused by pathogenic variants predominantly of the mitochondrial DNA (mtDNA). Canonical clinical features of MERRF include myoclonus, epilepsy, ataxia, and myopathy. Additionally, other manifestations in the CNS, peripheral nerves, eyes, ears, heart, gastrointestinal tract, and endocrine organs may occur (MERRF-plus). Today, MERRF is considered rather as myoclonic ataxia than as myoclonic epilepsy. Genotypically, MERRF is due to mutations in 13 mtDNA-located genes and 1 nDNA-located gene. According to the modified Smith-score, the strongest gene-disease relationship exists for MT-TK, MT-TL1, and POLG1. Epilepsy is the second most frequent phenotypic feature of MERRF. Seizure-types associated with MERRF include focal myoclonic, focal clonic, and focal atonic seizures, generalized myoclonic, tonic-clonic, atonic, and myoclonic-atonic seizures, or typical absences. Treatment of myoclonic epilepsy relies on expert judgments recommending levetiracetam, together with clonazepam, or topiramate, zonisamide, or piracetam in monotherapy as the first line AEDs.
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Affiliation(s)
- Josef Finsterer
- a Krankenanstalt Rudolfstiftung , Messerli Institute , Vienna , Austria
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Shen C, Xian W, Zhou H, Li X, Liang X, Chen L. Overlapping Leigh Syndrome/Myoclonic Epilepsy With Ragged Red Fibres in an Adolescent Patient With a Mitochondrial DNA A8344G Mutation. Front Neurol 2018; 9:724. [PMID: 30271374 PMCID: PMC6146370 DOI: 10.3389/fneur.2018.00724] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/08/2018] [Indexed: 12/24/2022] Open
Abstract
We present the case of a 16-year-old boy with a family history of epilepsy who presented with acute respiratory failure, limb weakness, diabetes mellitus, sinus tachycardia, lactic acidosis, and pneumonia. He went on to develop cranial nerve palsy, myoclonus, generalized seizures, ataxia, recurrent pneumonia, and hypotension. Biochemical investigation revealed elevated lactate, pyruvate, and glucose levels. Cerebral magnetic resonance imaging (MRI) revealed bilateral, symmetric, high-intensity T2-weighted signals in the thalamus, brainstem, and gray matter of the spinal cord. Histochemical analyses revealed ragged red fibers (RRF) and decreased cytochrome oxidase activity. Blood and muscle-derived DNA demonstrated a high level (95% and 96%, respectively) of the m.8344A>G mutation, while almost all of his maternal relatives (n = 17, including his mother) carried the same point mutation. The point mutation level of his mother (who had short stature, high blood lactate levels, and epilepsy) was 77% (blood-derived DNA). Although this mutation has been identified in approximately 30 individuals with these disorders, to our knowledge, this is the first reported case of overlapping Leigh syndrome/myoclonic epilepsy with RRF in an adolescent patient, and the largest reported pedigree of mitochondrial DNA A8344G mutation.
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Affiliation(s)
- Cunzhou Shen
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Wenbiao Xian
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Hongyan Zhou
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Xunhua Li
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Xiuling Liang
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Ling Chen
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
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Abstract
BACKGROUND Given the etiologic heterogeneity of disease classification using clinical phenomenology, we employed contemporary criteria to classify variants associated with myoclonic epilepsy with ragged-red fibers (MERRF) syndrome and to assess the strength of evidence of gene-disease associations. Standardized approaches are used to clarify the definition of MERRF, which is essential for patient diagnosis, patient classification, and clinical trial design. METHODS Systematic literature and database search with application of standardized assessment of gene-disease relationships using modified Smith criteria and of variants reported to be associated with MERRF using modified Yarham criteria. RESULTS Review of available evidence supports a gene-disease association for two MT-tRNAs and for POLG. Using modified Smith criteria, definitive evidence of a MERRF gene-disease association is identified for MT-TK. Strong gene-disease evidence is present for MT-TL1 and POLG. Functional assays that directly associate variants with oxidative phosphorylation impairment were critical to mtDNA variant classification. In silico analysis was of limited utility to the assessment of individual MT-tRNA variants. With the use of contemporary classification criteria, several mtDNA variants previously reported as pathogenic or possibly pathogenic are reclassified as neutral variants. CONCLUSIONS MERRF is primarily an MT-TK disease, with pathogenic variants in this gene accounting for ~90% of MERRF patients. Although MERRF is phenotypically and genotypically heterogeneous, myoclonic epilepsy is the clinical feature that distinguishes MERRF from other categories of mitochondrial disorders. Given its low frequency in mitochondrial disorders, myoclonic epilepsy is not explained simply by an impairment of cellular energetics. Although MERRF phenocopies can occur in other genes, additional data are needed to establish a MERRF disease-gene association. This approach to MERRF emphasizes standardized classification rather than clinical phenomenology, thus improving patient diagnosis and clinical trial design.
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Yu N, Zhang YF, Zhang K, Xie Y, Lin XJ, Di Q. MELAS and Kearns-Sayre overlap syndrome due to the mtDNA m. A3243G mutation and large-scale mtDNA deletions. eNeurologicalSci 2016; 4:15-18. [PMID: 29430542 PMCID: PMC5803102 DOI: 10.1016/j.ensci.2016.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 04/17/2016] [Accepted: 04/23/2016] [Indexed: 01/21/2023] Open
Abstract
This paper reported an unusual manifestation of a 19-year-old Chinese male patient presented with a complex phenotype of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome and Kearns-Sayre syndrome (KSS). He was admitted to our hospital with the chief complaint of "acute fever, headache and slow reaction for 21 days". He was initially misdiagnosed as "viral encephalitis". This Chinese man with significant past medical history of intolerating fatigue presented paroxysmal neurobehavioral attacks that started about 10 years ago. During this span, 3 or 4 attack clusters were described during which several attacks occurred over a few days. The further examination found that the hallmark signs of this patient included progressive myoclonus epilepsy, cerebellar ataxia, hearing loss, myopathic weakness, ophthalmoparesis, pigmentary retinopathy and bifascicular heart block (Wolff-Parkinson-White syndrome). By young age the disease progression is characterized by the addition of migraine, vomiting, and stroke-like episodes, symptoms of MELAS expression, which indicated completion of the MELAS/KSS overlap syndrome. The m. A3243G mitochondrial DNA mutation and single large-scale mtDNA deletions were found in this patient. This mutation has been reported with MELAS, KSS, myopathy, deafness and mental disorder with cognitive impairment. This is the first description with a MELAS/KSS syndrome in Chinese.
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Affiliation(s)
| | | | | | | | | | - Qing Di
- Nanjing Medical University, Affiliated Nanjing Brain Hospital, Department of Neurology, 210029 Nanjing, China
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Kelland E, Rupar C, Prasad AN, Tay K, Downie A, Prasad C. Response to: Letter to the Editor Regarding: The Expanding Phenotype of MELAS Caused by the m.3291 T > C tRNA Mutation E Kelland, C. A. Rupar, Asuri N. Prasad, K. Y. Tay, A. Downie and C. Prasad (1) by Josef Finsterer, MD, PhD [1], Sinda Zarrouk-Mahjoub, PhD [2] [1] Krankenanstalt Rudolfstiftung, Vienna [2] Genomics Platform, Pasteur Institute of Tunis, Tunisia. Mol Genet Metab Rep 2016; 8:41-2. [PMID: 27493879 PMCID: PMC4963257 DOI: 10.1016/j.ymgmr.2016.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 07/07/2016] [Indexed: 11/18/2022] Open
Affiliation(s)
- E. Kelland
- Department of Pediatrics, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
| | - C.A. Rupar
- Department of Pediatrics, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Department of Biochemistry, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Department of Pathology and Laboratory Medicine, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Children's Health Research Institute, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Western University, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
| | - Asuri N. Prasad
- Department of Pediatrics, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Department of Neurology, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Children's Health Research Institute, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Western University, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
| | - K.Y. Tay
- Medical Imaging, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Western University, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
| | - A. Downie
- Western University, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Paediatric Psychology, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
| | - C. Prasad
- Department of Pediatrics, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Children's Health Research Institute, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Western University, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
- Corresponding author at: Department of Pediatrics, Children's Hospital London Health Sciences Centre, London, Ontario, Canada.Department of PediatricsChildren's Hospital London Health Sciences CentreLondonOntarioCanada
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Response to: Letter to the Editor regarding: The expanding phenotype of MELAS caused by the m.3291T>C tRNA mutation E. Kelland, C.A. Rupar, Asuri N. Prasad, A. Downie and C. Prasad (1) by Josef Finsterer, MD, PhD [1], Sinda Zarrouk-Mahjoub, PhD [2]. Mol Genet Metab Rep 2016; 7:96-7. [PMID: 27331010 PMCID: PMC4901176 DOI: 10.1016/j.ymgmr.2016.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 05/09/2016] [Indexed: 11/23/2022] Open
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Keilland E, Rupar CA, Prasad AN, Tay KY, Downie A, Prasad C. The expanding phenotype of MELAS caused by the m.3291T > C mutation in the MT-TL1 gene. Mol Genet Metab Rep 2016; 6:64-9. [PMID: 27014580 PMCID: PMC4789386 DOI: 10.1016/j.ymgmr.2016.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 02/11/2016] [Accepted: 02/11/2016] [Indexed: 11/28/2022] Open
Abstract
m.3291T > C mutation in the MT-TL1 gene has been infrequently encountered in association with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS), however remains poorly characterized from a clinical perspective. In the following report we describe in detail the phenotypic features, long term follow up (> 7 years) and management in a Caucasian family with MELAS due to the m.3291T > C mutation and review the literature on m.3291T > C mutation. The clinical phenotype in the proposita included overlapping features of MELAS, MERRF (Myoclonic epilepsy and ragged-red fiber syndrome), MNGIE (Mitochondrial neurogastrointestinal encephalopathy), KSS (Kearns-Sayre Syndrome) and CPEO (Chronic progressive external ophthalmoplegia).
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Affiliation(s)
- E Keilland
- Department of Pediatrics, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
| | - C A Rupar
- Department of Pediatrics, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Department of Biochemistry, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Department of Pathology and Laboratory Medicine, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Children's Health Research Institute, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Western University, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
| | - Asuri N Prasad
- Department of Pediatrics, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Department of Neurology, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Children's Health Research Institute, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Western University, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
| | - K Y Tay
- Medical Imaging, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Western University, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
| | - A Downie
- Western University, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Paediatric Psychology, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
| | - C Prasad
- Department of Pediatrics, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Children's Health Research Institute, Children's Hospital London Health Sciences Centre, London, Ontario, Canada; Western University, Children's Hospital London Health Sciences Centre, London, Ontario, Canada
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14
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Liu K, Zhao H, Ji K, Yan C. MERRF/MELAS overlap syndrome due to the m.3291T>C mutation. Metab Brain Dis 2014; 29:139-44. [PMID: 24338029 DOI: 10.1007/s11011-013-9464-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 11/26/2013] [Indexed: 10/25/2022]
Abstract
We report the case of a 19-year-old Chinese female harboring the m.3291T>C mutation in the MT-TL1 gene encoding the mitochondrial transfer RNA for leucine. She presented with a complex phenotype characterized by progressive cerebellar ataxia, frequent myoclonus seizures, recurrent stroke-like episodes, migraine-like headaches with nausea and vomiting, and elevated resting lactate blood level. It is known that the myoclonus epilepsy with ragged-red fibers (MERRF) is characterized by cerebellar ataxia and myoclonus epilepsy, while that the mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is characterized by recurrent stroke-like episodes, migraine-like headaches, and elevated resting lactate blood level. So the patient's clinical manifestations suggest the presence of a MERRF/MELAS overlap syndrome. Muscle biopsy of the patient showed the presence of numerous scattered ragged-red fibers, some cytochrome c oxidase-deficient fibers, and several strongly succinate dehygrogenase-reactive vessels, suggestive of a mitochondrial disorder. Direct sequencing of the complete mitochondrial genome of the proband revealed no mutations other than the T-to-C transition at nucleotide position 3291. Restriction fragment length polymorphism analysis of the proband and her family revealed maternal inheritance of the mutation in a heteroplasmic manner. The analysis of aerobic respiration and glycolysis demonstrated that the fibroblasts from the patient had mitochondrial dysfunction. Our results suggest that the m.3291T>C is pathogenic. This study is the first to describe the m.3291T>C mutation in association with the MERRF/MELAS overlap syndrome.
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Affiliation(s)
- Kaiming Liu
- Laboratory of Neuromuscular Disorders and Department of Neurology, Qilu Hospital, Shandong University, Jinan, 250012, China
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Finsterer J, Zarrouk Mahjoub S. Mitochondrial epilepsy in pediatric and adult patients. Acta Neurol Scand 2013; 128:141-52. [PMID: 23480231 DOI: 10.1111/ane.12122] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2013] [Indexed: 01/04/2023]
Abstract
Few data are available about the difference between epilepsy in pediatric mitochondrial disorders (MIDs) and adult MIDs. This review focuses on the differences between pediatric and adult mitochondrial epilepsy with regard to seizure type, seizure frequency, and underlying MID. A literature search via Pubmed using the keywords 'mitochondrial', 'epilepsy', 'seizures', 'adult', 'pediatric', and all MID acronyms, was carried out. Frequency of mitochondrial epilepsy strongly depends on the type of MID included and is higher in pediatric compared to adult patients. In pediatric patients, mitochondrial epilepsy is more frequent due to mutations in nDNA-located than mtDNA-located genes and vice versa in adults. In pediatric patients, mitochondrial epilepsy is associated with a syndromic phenotype in half of the patients and in adults more frequently with a non-syndromic phenotype. In pediatric patients, focal seizures are more frequent than generalized seizures and vice versa in adults. Electro-clinical syndromes are more frequent in pediatric MIDs compared to adult MIDs. Differences between pediatric and adult mitochondrial epilepsy concern the onset of epilepsy, frequency of epilepsy, seizure type, type of electro-clinical syndrome, frequency of syndromic versus non-syndromic MIDs, and the outcome. To optimize management of mitochondrial epilepsy, it is essential to differentiate between early and late-onset forms.
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Affiliation(s)
| | - S. Zarrouk Mahjoub
- Laboratory of Biochemistry; UR ‘Human Nutrition and Metabolic Disorders’ Faculty of Medicine Monastir; Tunisia
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Mkaouar-Rebai E, Chamkha I, Mezghani N, Ben Ayed I, Fakhfakh F. Screening of mitochondrial mutations in Tunisian patients with mitochondrial disorders: an overview study. ACTA ACUST UNITED AC 2013; 24:163-78. [PMID: 23301511 DOI: 10.3109/19401736.2012.748045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
To investigate the spectrum of common mitochondrial mutations in Tunisia during the years of 2002-2012, 226 patients with mitochondrial disorders were clinically diagnosed with hearing loss, Leigh syndrome (LS), diabetes, cardiomyopathy, Kearns-Sayre syndrome (KSS), Pearson syndrome (PS), myopathy, mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes syndrome (MELAS) and Wolfram syndrome. Restriction fragment length polymorphism (PCR-RFLP), radioactive PCR, single specific primer-PCR (SSP-PCR) analysis and PCR-sequencing methods were used to identify the mutations. Two cases with m.1555A>G mutation and two families with the novel 12S rRNA m.735A>G transition were detected in patients with hearing loss. Three cases with m.8993T>G mutation, two patients with the novel m.5523T>G and m.5559A>G mutations in the tRNA(Trp) gene, and two individuals with the undescribed m.9478T>C mutation in the cytochrome c oxidase subunit III (COXIII) gene were found with LS. In addition, one case with hypertrophic cardiomyopathy and deafness presented the ND1 m.3395A>G mutation and the tRNA(Ile) m.4316A>G variation. Besides, multiple mitochondrial deletions were detected in patients with KSS, PS, and Wolfram syndrome. The m.14709T>C mutation in the tRNA(Glu) was reported in four maternally inherited diabetes and deafness patients and a novel tRNA(Val) m.1640A>G mutation was detected in a MELAS patient.
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Affiliation(s)
- Emna Mkaouar-Rebai
- Human Molecular Genetic Laboratory, Faculty of Medicine of Sfax, Avenue Magida Boulila, 3029 Sfax, Tunisia.
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Abstract
The mitochondrial DNA (mtDNA) is a compact genome inherited through the maternal lineage. Mutations in mtDNA lead to many of the earliest identified syndromic mitochondrial diseases and display a diverse range of age of onset, symptoms, and outcomes-from isolated childhood onset vision or hearing loss to a multisystemic neurodegenerative disorder with strokes, neuropathy, ophthalmoparesis, and epilepsy beginning at any age. As a heterogeneous group, mitochondrial diseases represent one of the most common metabolic disorders in children and adults, frequently seen by both pediatric and adult specialists. Although the myriad of diseases can make diagnosis seems daunting, the need for extensive supportive care and treatment (the latter for at least a select few mitochondrial disorders) and a rapid and accurate recognition of these disorders is necessary. Here, we provide a review of the most common mitochondrial disease syndromes due to mtDNA mutations.
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Affiliation(s)
- Suzanne Debrosse
- Center for Human Genetics, University Hospitals, Case Medical Center, Cleveland, OH 44195, USA
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