Dystonia in homocystinuria.

Three patients with homocystinuria due to cystathionine beta-synthase deficiency who developed progressive generalised dystonia are described. Although cerebrovascular thrombosis is usually thought to be responsible for neurological dysfunction in homocystinuric patients, neuropathological studies in one case and clinical and radiological evidence in the other two suggested that dystonia was not caused by brain infarction. Movement disorder associated with homocystinuria may result from the neurochemical changes in the basal ganglia related to the inherited defect in sulphur amino acid metabolism.