RAPID-ONSET DYSTONIA-PARKINSONISM

We studied a large family with a previously undescribed, autosomal dom inant dystonia-parkinsonism syndrome. We chose to call the disorder '' rapid-onset dystonia-parkinsonism'' (RDP) based on the unusually rapid evolution of signs and symptoms. Affected individuals developed dysto nia and parkinsonism between 14 and 45 years of age. The onset was acu te in six individuals with the abrupt onset of symptoms over the cours e of several hours, and subacute in four others who had evolution over several days or weeks. Thereafter, progression of symptoms was usuall y very slow. Two had intermittent focal dystonia without parkinsonism, and one obligate gene carrier was asymptomatic at 68 years. CSF level s of homovanillic acid were decreased in the two individuals tested, b ut dopaminergic therapy provided only slight benefit. The DYT1 gene re sponsible for early-onset, generalized idiopathic torsion dystonia in Jewish and some non-Jewish families has been mapped to chromosome 9q34 . Linkage analysis with three markers near the DYT1 gene showed severa l obligate recombinations, excluding DYT1 as a candidate gene for RDP. We believe RDP is unique and should be classified separately from oth er forms of hereditary dystonia-parkinsonism.