Dystonia in Spain: study of a Gypsy family and general survey.

A girl from a Spanish Gypsy family developed idiopathic torsion dystonia when 12 years old. Parents were first cousins and both the pattern of clinical involvement and the rate of progression corresponded to that usually found in the autosomal recessive form of the disorder. Serum dopamin-beta-hydroxylase activity in the patient and close family members were also in keeping with this hereditary form. A nationwide inquiry failed to detect further cases of torsion dystonia among Gypsies, but revealed a relatively large number of recessively inherited disorders of the nervous system in this inbred, genetically isolated population. Thirty-six additional cases of torsion dystonia were collected from the general Spanish population, including four with a family history for this condition. The gene responsible for the recessive illness appears to be rare in many countries, explaining the sporadic nature of the disorder and its eventual appearance only in genetic isolates or after consanguineous matings.