Mitochondrial myopathy with dystrophic features due to a novel mutation in the MTTM gene.

ABSTRACT: 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].Sequencing of the whole mtDNA, assessment of the mutation load in muscle and accessible nonmuscle tissues, and single fiber polymerase chain reaction.Muscle mitochondrial DNA (mtDNA) sequencing revealed a novel heteroplasmic mutation (m.4403G>A) in the gene (MTTM) that encodes tRNA(Met). The mutation was not present in accessible nonmuscle tissues from the patient or 2 asymptomatic sisters.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.

SUBMITTER: Peverelli L 

PROVIDER: S-EPMC4107085 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature