TISSUE-SPECIFIC INVOLVEMENT OF MULTIPLE MITOCHONDRIAL-DNA DELETIONS IN FAMILIAR MITOCHONDRIAL MYOPATHY

It is still uncertain how deleted mitochondrial DNA (mtDNA) is distrib uted to each tissue during development, although deletions of mtDNA ha ve been extensively observed in various pathologic conditions. This pa per presents two Japanese siblings with progressive external ophthalmo plegia exhibiting multiple mtDNA deletions. In one patient, similar mu ltiple mtDNA deletions were found in skeletal muscle specimens as well as in the spinal cord brat not in the myocardium, liver or leukocytes , A similar deletion pattern was found in the skeletal muscle but not in the leukocytes of the other patient, The results suggest the comple x mechanism to generate, expand and eliminate the deleted mtDNA in hum ans. (C) 1998 Academic Press.