A MERRF PEO OVERLAP SYNDROME-ASSOCIATED WITH THE MITOCHONDRIAL-DNA-3243 MUTATION/

We describe a two-generation family with combined clinical features of myoclonic epilepsy, progressive external ophthalmoplegia (PEG), proxi mal myopathy, pigmentary retinopathy, progressive deafness, basal gang lia calcification, and ragged-red fibers in a muscle biopsy specimen. One family member died unexpectedly at age 22 years. The molecular tes ts revealed an A-to-G transition at nucleotide position 3243 of the mi tochondrial tRNA(Leu(UUR)) gene. No one in this family had stroke-like episodes. Although the propositus (a 28-year-old woman) had a signifi cant number of white hairs, the percentage of mutant mtDNA in white-ha ir roots was not different from that in the colored-hair roots, Our fi ndings suggest that the 3243 mutation can be associated with mixed cli nical features of myoclonic epilepsy with ragged-red fibers (MERRF) an d PEO and that a preferential increase in the levels of the mutant mtD NA is not related to graying of hair, and hence to the hypothesized pr oduction of premature aging of cells.