A nonsense mutation (G15059A) in the cytochrome b gene in a patient with exercise intolerance and myoglobinuria

Ann Neurol. 1999 Jan;45(1):127-30. doi: 10.1002/1531-8249(199901)45:1<127::aid-art20>3.0.co;2-y.


We describe a new mitochondrial DNA mutation in the cytochrome b gene in a patient presenting with progressive exercise intolerance and myoglobinuria associated with complex III deficiency in muscle. The point mutation results in the replacement of a glycine at amino acid position 190 with a stop codon. This change predicts premature termination of translation, leading to a truncated protein missing 244 amino acids at the C-terminus of cytochrome b. The mutation fulfills all the accepted criteria for pathogenicity, suggesting that this is the primary cause of the myopathy in the patient.

Publication types

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

MeSH terms

  • Adult
  • Codon, Terminator
  • Cytochrome b Group / genetics*
  • DNA Mutational Analysis
  • Electron Transport Complex IV / analysis
  • Humans
  • Male
  • Muscle Fatigue / genetics*
  • Muscle, Skeletal / enzymology
  • Myoglobinuria / genetics*
  • Physical Exertion*
  • Point Mutation*
  • Succinate Dehydrogenase / analysis


  • Codon, Terminator
  • Cytochrome b Group
  • Succinate Dehydrogenase
  • Electron Transport Complex IV