DUPLICATIONS OF MITOCHONDRIAL-DNA IN KEARNS-SAYRE SYNDROME

mtDNA duplications were detectable in 10 of 10 patients with mtDNA del etions and Kearns-Sayre syndrome (KSS) and in none of 8 patients with chronic progressive external ophthalmoplegia (CPEO), Thus, duplication s of mtDNA seem to be a distinctive feature of KSS, including patients where Pearson's syndrome is the first manifestation, Diabetes mellitu s was identified in 4 of 7 patients with high or moderate levels of mt DNA duplications. The balance of mtDNA rearrangements may be central t o the pathogenesis of this unique group of disorders, (C) 1995 John Wi ley and Sons, Inc.