A genetic study of torsion dystonia

Abstract

A family study of 32 patients with torsion dystonia showed at least 2 forms of generalized dystonia with onset in childhood. These 2 forms, an autosomal dominant and an autosomal recessive, were clinically indistinguishable. There were at least 3 families and probably about 6 to 8 patients with the autosomal recessive variety. The remaining 9 to 11 patients with generalized childhood dystonia were thought, because of a probable paternal age effect, to be examples of new dominant mutations. Since fitness with childhood onset is 1/20 of normal, most childhood dominant cases appeared sporadically. Most of the other 15 patients (12 with onset in adult life) appeared to have a non genetic torsion dystonia, although an example of a benign adult onset dominant form associated with a tremor was observed. It is concluded that there are at least 2 forms of genetic torsion dystonia, an autosomal recessive form with onset in childhood, which, on evidence from America, is particularly common in Ashkenazi Jews, and 1 or more dominant forms, with onset in childhood or adult life. The majority of adult onset isolated cases of idiopathic torsion dystonia seem to be due to exogenous but unidentified causes.