The mutation frequency in our group was slightly higher but comparable with results obtained by other authors in unselected primary dystonia or DYT1-negative dystonia patients (1–2.5%) [8,16,17], however much lower than reported in groups of subjects restricted by age or family history (e.g. 25% in patients with onset under 22 and a positive familial history) [18]. This evidence concerns the gene TOR1A and Dystonia.