Focal and segmental primary dystonia in north-western Germany--a clinico-genetic study

To determine the frequency of familial focal and segmental dystonias in a large patient cohort with primary dystonia from north-western Germany.

In this study, 130 patients with focal or segmental dystonia were examined and a family history was obtained. Whenever possible, affected relatives were examined (a total of 789 first-degree relatives). Data on disease duration, age at disease onset and age of the patients were investigated by Student's t-test and a segregation analysis was performed by Weinberg's proband method.

Age at onset of disease was significantly later in the blepharospasm group. Only in the writer's cramp group were women outnumbered by men. A positive family history was found in 15 of the 130 index patients (11.5%). None of 102 index patients tested carried the GAG deletion in the DYT1 gene.

In accordance with previous series our study provides evidence that primary focal dystonia may have a genetic etiology, most probably caused by an autosomal dominant trait with reduced penetrance.