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A novel mutation in the mitochondrial tRNA Val gene associated with a complex neurological presentation
Author(s) -
Tiranti Valeria,
D'Agruma Leonardo,
Pareyson Davide,
Mora Marina,
St Franco Carrara,
Zelante Leopoldo,
Gasparini Paolo,
Zeviani Massimo
Publication year - 1998
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410430116
Subject(s) - heteroplasmy , mitochondrial dna , mitochondrial myopathy , proband , ataxia , genetics , non mendelian inheritance , mitochondrial encephalomyopathies , biology , myopathy , mutation , gene , cytochrome c oxidase , mutant , mitochondrial respiratory chain , mitochondrion , medicine , neuroscience
We describe a patient who presented with progressive ataxia, sezures, mental deterioration, mild myopathy, and hearing loss. A novel heteroplasmic G‐to‐A transition was found, affecting the acceptor stem of the mitochondrial (mt) tRNA Val gene. Mutant mtDNA was 67% of total mtDNA in the muscle of the proband and was also present at low levels in the muscle of his healthy mother. It was absent in all of the numerous control DNA samples that were tested. Analysis of single muscle fibers revealed a significantly greater level of mutant mtDNA in cytochrome c oxidase‐negative fibers. Mutations of mtDNA may be responsible of neurological syndromes that, like the case reported here, are clinically puzzling, and lack typical “mitochondrial” clues, such as elevated levels of blood lactate, overt defects of the respiratory complexes, and clinically documented maternal inheritance.