A new mtDNA mutation associated with a progressive encephalopathy and cytochrome c oxidase deficiency

Neurology. 2000 Apr 25;54(8):1693-6. doi: 10.1212/wnl.54.8.1693.


The authors describe a novel pathogenic G5540A transition in the mitochondrial transfer RNA (tRNA)Trp gene of a sporadic encephalomyopathy characterized by spinocerebellar ataxia. Clinical features also included neurosensorial deafness, peripheral neuropathy, and dementia. Biochemistry revealed a severe reduction of cytochrome c oxidase (COX) activity. Single-fiber PCR demonstrated higher levels of mutant genomes in COX-negative ragged red fibers than in normal fibers. These findings confirm that COX is more susceptible than other respiratory chain complexes to mutations in the mitochondrial tRNATrp gene.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Biopsy
  • Cytochrome-c Oxidase Deficiency*
  • DNA Mutational Analysis
  • DNA, Mitochondrial / genetics*
  • Dementia / etiology
  • Disease Progression
  • Fatal Outcome
  • Female
  • Hearing Loss, Sensorineural / etiology
  • Humans
  • Mitochondria, Muscle / enzymology
  • Mitochondria, Muscle / pathology
  • Mitochondrial Encephalomyopathies / complications
  • Mitochondrial Encephalomyopathies / diagnosis*
  • Mitochondrial Encephalomyopathies / genetics*
  • Muscle, Skeletal / enzymology
  • Muscle, Skeletal / pathology
  • Point Mutation / genetics*
  • RNA, Transfer, Trp / genetics*
  • Spinocerebellar Ataxias / etiology


  • DNA, Mitochondrial
  • RNA, Transfer, Trp

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