Mitochondrial myopathy with dystrophic features due to a novel mutation in the MTTM gene |
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| Authors: | Lorenzo Peverelli MD Carl A. Gold MD Ali B. Naini PhD Kurenai Tanji MD H. Orhan Akman PhD Michio Hirano MD Salvatore Dimauro MD |
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| Affiliation: | 1. Department of Neurology, Columbia University Medical Center, College of Physicians & Surgeons, , New York, New York, USA;2. Department of Pathology, Columbia University Medical Center, College of Physicians & Surgeons, , New York, New York, USA |
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| Abstract: | Introduction: A 61‐year‐old woman with a 5‐year history of progressive muscle weakness and atrophy had a muscle biopsy characterized by a combination of dystrophic features (necrotic fibers and endomysial fibrosis) and mitochondrial alterations [ragged‐red, cytochrome c oxidase (COX)‐negative fibers]. Methods: Sequencing of the whole mtDNA, assessment of the mutation load in muscle and accessible nonmuscle tissues, and single fiber polymerase chain reaction. Results: Muscle mitochondrial DNA (mtDNA) sequencing revealed a novel heteroplasmic mutation (m.4403G>A) in the gene (MTTM) that encodes tRNAMet. The mutation was not present in accessible nonmuscle tissues from the patient or 2 asymptomatic sisters. Conclusions: The clinical features and muscle morphology in this patient are very similar to those described in a previous patient with a different mutation, also in MTTM, which suggests that mutations in this gene confer a distinctive “dystrophic” quality. This may be a diagnostic clue in patients with isolated mitochondrial myopathy. Muscle Nerve 50:292–295, 2014 |
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| Keywords: | de novo mutation dystrophic features late‐onset weakness mitochondrial myopathy mtDNA tRNAMet |
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