A novel myopathy-associated mitochondrial DNA mutation altering the conserved size of the tRNA(Gln) anticodon loop

Runu Dey, Celia H. Tengan, Maria P.A. Morita, Beatriz H. Kiyomoto, Carlos T. Moraes

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

We report a novel mitochondrial DNA alteration in a 12-year-old boy with myopathy. We identified a single nucleotide insertion (an adenine) in the mitochondrial tRNA-glutamine gene. This addition of an additional adenine in a polyadenine stretch (at mitochondrial DNA positions 4366-4369), alters the length of the evolutionary conserved anticodon loop from seven to eight bases. The nt-4370 addition was heteroplasmic and was abundant in the patient's muscle. Lower proportions of mutated mitochondrial DNA were observed in skin fibroblasts, but were below detectable levels in white blood cells. A muscle biopsy of the patient showed ragged red fibers and an unusually high percentage of cytochrome c oxidase-deficient fibers (89%). The pathogenicity of the mutation was also evident by the fact that fibers harboring lower levels of the mutation showed normal cytochrome c oxidase activity. The insertion in the anticodon loop of tRNA(Gln) gene identified in our patient may provide a unique tool to study protein synthesis in human mitochondria. Copyright (C) 2000 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)488-492
Number of pages5
JournalNeuromuscular Disorders
Volume10
Issue number7
DOIs
StatePublished - Oct 1 2000

Keywords

  • Adenine
  • Myopathy
  • Novel mitochondrial DNA mutation
  • Nucleotide insertion

ASJC Scopus subject areas

  • Clinical Neurology
  • Pediatrics, Perinatology, and Child Health
  • Developmental Neuroscience
  • Neurology

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