Possible sporadic rapid-onset dystonia-parkinsonism.

Rapid-onset dystonia-parkinsonism is a hereditary disease characterized by a combination of dystonic and parkinsonian symptoms. Bulbar musculature is predominantly affected by dystonia. The onset is usually abrupt and the progression of the disease over years is minimal or absent. Homovanillic acid levels in cerebrospinal fluid can be diminished, suggesting that the pathogenesis of the disease is related to some dysfunction in dopaminergic neurotransmission. However, no abnormality has been found in positron emission tomography studies and levodopa does not improve symptoms. The genetic abnormality is not known, but evidence for linkage to markers on chromosome 19q13 has been reported. We describe the case of a woman with a clinical picture highly suggestive of rapid onset dystonia-parkinsonism (RDP) and no family history of the disease.