To investigate the DYT1 gene mutation in Chinese ethnic, we examined a series of 200 patients with primary dystonias (11 familial and 189 sporadic), 53 of their asymptomatic relatives, 97 patients with familial or early-onset parkinsonism, and 200 healthy subjects. The GAG deletion at codon 946 was only found in three sporadic dystonia patients and seven of their asymptomatic familial members. The frequency of GAG deletion was 1.5% in dystonia patients, and was 6.7% in early-onset dystonias (< or = 26 years). We conclude that DYT1 mutation is a minor cause of primary dystonias in a cohort of Taiwanese population.