Variable phenotype of rapid-onset dystonia-parkinsonism.

Rapid-onset dystonia-parkinsonism (RDP) is an autosomal dominant disorder characterized by the rapid onset of dystonic spasms and parkinsonism over a period of a few hours to weeks after their onset. We have seen two additional members of this previously reported family with RDP who present with a more gradual progression of their disorder over 6-18 months. One of these individuals experienced the rapid progression of symptoms 2 years after an initial stabilization of his condition. The RDP phenotype is variable, and presentation may be gradual in some cases. Cerebrospinal fluid neurotransmitter levels in these two and other family members suggest involvement of the dopaminergic pathways in RDP.