MITOCHONDRIAL DISEASE WITH CHRONIC PROGRE SSIVE EXTERNAL OPHTHALMOPLEGIA - CLINICAL, HISTOENZYMATIC, BIOCHEMICAL AND GENETIC-ANALYSIS OF 9 CASES

We report the clinical signs and histological findings in nine patient s with mitochondrial ocular myopathies. There wee four males and five females. Of age ranging from 47 to 82 years. A more often asymetrical ptosis was in all cases of chronic progressive external ophtalmoplegia (CPEO), but muscle weakness in limbs was not usual. The prognosis in this group was good, but ubidecarenone (150 mg/d) used for two cases, did not improve ophtalmoplegia. The serum creatine kinase was normal i n eight of nine cases and electromyography showed myopathic changes in three cases. Histoenzymatic analysis of the muscle biopsy and biochem ical studies of mitochondria isolated from the muscle sample demonstra ted mitochondrial myopathy associated with partial deficiency of compl exes I and/or IV of the electron transfer chain. One of seven patients studied had single deletion by Southern blot analysis, in a heteropla smic state and another an A --> G transition at position 3243 within t he mitochondrial tRNA leu (UUR) gene. Chronic progressive external oph talmoplegia, without large deletion, may have abnormality in other cod ing regions of mt DNA such as tRNA, rRNA or protein genes.