Maternally inherited cardiomyopathy and hearing loss associated with a novel mutation in the mitochondrial tRNA(Lys) gene (G8363A)

Author(s): Mak, S. C., Elschahawi, M., Casali, C., Shanske, S., Baram, T. Z., Madrid, R. E., Dimauro, S.

Journal/Book: Am J Hum Genet. 1996; 58: 5720 S Woodlawn Ave, Chicago, IL 60637. Univ Chicago Press. 933-939.

Abstract: A novel G8363A mutation in the mtDNA tRNA(Lys) gene was associated, in two unrelated families, with a syndrome consisting of encephalomyopathy, sensorineural hearing loss, and hypertrophic cardiomyopathy. Muscle biopsies from the probands showed mitochondrial proliferation and partial defects of complexes I, III, and IV of the electron-transport chain. The G8363A mutation was very abundant (> 95%) in muscle samples from the probands and was less copious in blood from 18 maternal relatives (mean 81.3% +/- 8.5%). Single-muscle-fiber analysis showed significantly higher levels of mutant genomes in cytochrome c oxidase-negative fibers than in cytochrome c oxidase-positive fibers. The mutation was not found in > 200 individuals, including normal controls and patients with other mitochondrial encephalomyopathies, thus fulfilling accepted criteria for pathogenicity.

Note: Article S Dimauro, Columbia Univ Coll Phys & Surg, Dept Neurol, H Houston Merrit Ctr, Muscular Res & Related Disor, New York, NY 10032 USA

Keyword(s): CLINICAL-FEATURES; DNA; MELAS; MTDNA

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