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

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