[Chronic progressive external ophthalmoplegia with mitochondrial anomalies. Clinical, histological, biochemical and genetic analysis (9 cases)].

We report the clinical signs and histological findings in nine patients with mitochondrial ocular myopathies. There were 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 in eight of nine cases and electromyography showed myopathic changes in three cases. Histoenzymatic analysis of the muscle biopsy and biochemical studies of mitochondria isolated from the muscle sample demonstrated mitochondrial myopathy associated with partial deficiency of complexes I and/or IV of the electron transfer chain. One of seven patients studied had single deletion by Southern blot analysis, in a heteroplasmic state and another an A-->G transition at position 3243 within the mitochondrial tRNA leu (UUR) gene. Chronic progressive external ophtalmoplegia, without large deletion, may have abnormality in other coding regions of mt DNA such as tRNA, rRNA or protein genes.