Abstract
Mitochondrial disorders are often associated with mutations in mitochondrial tRNA. Independent observation of the same molecular defect in unrelated subjects is a generally required proof of pathogenicity. A sporadic case of chronic external ophthalmoplegia (cPEO) with ragged red fibres (RRFs) has been previously related to an m.12316G>A substitution in tRNALeu(CUN). Sequencing muscle-derived mtDNA, we found the m.12316G>A substitution in an adult woman with mitochondrial myopathy and respiratory impairment. Her muscle biopsy presented several cytochrome c oxidase-negative (COX-) fibres, and RRFs as signs of mitochondrial proliferation. Restriction-fragment length polymorphism (RFLP) analysis of the mutation in isolated muscle fibres showed a threshold of at least 60% of mutated mtDNA to determine a COX deficiency phenotype. This second report of the m.12316G>A mutation in a sporadic patient consolidates its pathogenic nature and provides further elements for genetic counselling.
Original language | English |
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Pages (from-to) | 107-110 |
Number of pages | 4 |
Journal | Journal of the Neurological Sciences |
Volume | 292 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - May 15 2010 |
Keywords
- Late-onset myopathy
- mtDNA
- tRNA
ASJC Scopus subject areas
- Clinical Neurology
- Neurology