MULTIPLE DELETIONS OF MITOCHONDRIAL-DNA IN SPORADIC AND ATYPICAL CASES OF ENCEPHALOMYOPATHY

Multiple deletions of mitochondrial DNA (mtDNA) were first identified in patients with mitochondrial encephalomyopathy with a clear mendelia n inheritance. We found this genetic alteration in four atypical and s poradic cases of mitochondrial encephalomyopathy, characterized by RRF and partial COX deficiency. One patient was affected by essential hyp erCPKemia, 1 by subacute onset flaccid tetraplegia and 2 by parkinsoni sm. Southern blot and PCR revealed mtDNA multiple deletions in muscle tissue of these patients. These findings indicate that these alteratio ns are not confined to the families with mendelian transmission, but c an be present in sporadic cases with heterogeneous phenotypic features .