MOVEMENT-DISORDERS AND MITOCHONDRIAL DYSFUNCTION

Primary defects of mitochondrial DNA leading to respiratory chain dysf unction have been described in association with dystonia, chorea and p arkinsonism. Myoclonus remains the commonest movement disorder associa ted with such defects. The genetic basis of Leigh's syndrome, which is frequently associated with movement disorders, may be mitochondrial o r nuclear. Respiratory chain dysfunction has been identified in Huntin gton's disease in addition to Parkinson's disease, but the cause and r elationship of this dysfunction to the pathogenesis of these common di sorders is not yet determined.