Plasma dopamine-beta-hydroxylase activity in spasmodic torticollis. A sibship study.

Spasmodic torticollis remains an ill-understood disease. A central deficit in neurotransmitter activity in the basal ganglia may be present in this disorder. In the present study, dopamine-beta-hydroxylase (DBH) activity has been evaluated in the plasma of patients suffering from spasmodic torticollis and in their sibship in 4 informative families. In 1 of these families, 2 brothers are affected with torticollis and they have high plasma DBH levels. In the 3 other families the plasma DBH values are within normal ranges in the probands and their first-degree relatives. The genetic study of plasma DBH activity allowed to discriminate between two forms of spasmodic torticollis, one, which is most likely linked to familial torsion dystonia, appears to be associated with altered dopaminergic activity, while the other, nonfamilial with normal sympathetic activity, is probably an idiopathic or sporadic form of spasmodic torticollis.