Mitochondrial myopathies: clinical and biochemical features of 30 patients with major deletions of muscle mitochondrial DNA

Ann Neurol. 1989 Dec;26(6):699-708. doi: 10.1002/ana.410260603.


Analysis of mitochondrial DNA (mtDNA) in muscle and blood from 72 patients with mitochondrial myopathy showed that 30 had major deletions of a variable proportion of muscle mtDNA. All of these 30 patients presented with progressive external ophthalmoplegia and limb weakness, and 8 had the additional features of the Kearns-Sayre syndrome. Of the 42 patients without detectable muscle mtDNA deletions, 10 had progressive external ophthalmoplegia and limb weakness, 2 had the Kearns-Sayre syndrome, 11 had limb weakness without extraocular involvement, and 19 had multisystem disorders predominantly affecting the central nervous system. Only 2 patients with mtDNA deletions had clinically affected relatives, compared with 10 of those without deletions. In the 4 patients with polarographic defects exclusively involving complex I (NADH coenzyme Q reductase), the deleted protein-coding genes were confined to those for complex I subunits. Thirteen other patients with apparently identical deletions had variable clinical and biochemical features. Immunoblots of complex I polypeptides from patients with deletions were either indistinguishable from controls or showed only a mild generalized decrease in all identifiable subunits.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Chromosome Deletion*
  • Cytochromes / genetics
  • DNA, Mitochondrial / analysis*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Mitochondria, Muscle / metabolism
  • Mitochondria, Muscle / pathology*
  • Muscular Diseases / genetics*


  • Cytochromes
  • DNA, Mitochondrial