The genetics of primary torsion dystonia.

Primary torsion dystonia is an idiopathic movement disorder presumably caused by abnormal function of the basal ganglia. The disorder may be inherited either as an autosomal dominant, autosomal recessive, or X-linked recessive trait. At least six forms of autosomal dominant torsion dystonia can be distinguished clinically. Linkage analysis in one form of autosomal dominant torsion dystonia permits the assignment of a "torsion dystonia locus" to the long arm of chromosome 9.