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

✍ Scribed by I. J. Holt; Dr A. E. Harding; J. M. Cooper; A. H. V. Schapira; A. Toscano; J. B. Clark; J. A. Morgan-Hughes

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 908 KB
• Volume: 26
• Category: Article
• ISSN: 0364-5134
• DOI: 10.1002/ana.410260603

✦ Synopsis

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.