The DYT1 Gene Mutation in Primary Torsion Dystonia without Familial Background

ABSTRACT

BACKGROUND: The DYT1 dystonia is primary torsion dystonia (PTD) caused by a GAG deletion in DYT1 gene on chromosome 9 and transmits as autosomal dominant trait. It usually begins as limb-onset dystonia in childhood and tends to spread to other sites and has been reported as the most common cause of early onset PTD in Ashkenazi Jews. However, the frequency of DYT1 mutation in Korean patients with sporadic PTD has not been reported. METHODS: We examined dystonia patients who visited the Neurologic Clinic of Asan Medical Center between Jan 2001 and March 2002. The sporadic PTD patients of them were screened by genotyping with their peripheral blood samples. RESULTS: The 66 patients with sporadic PTD were recruited and two of them showed DYT1 mutation on Chromosome 9. One patient had segmental dystonia with cervical onset; the other had generalized dystonia with left leg onset. None of the patients with focal dystonia showed a DYT1 mutation. CONCLUSIONS: The DYT1 dystonia comprise a small portion of PTD without familial history in Korea. The DYT1 gene test should be considered in the early-onset or spreading type dystonia despite the absence of familial background in primary dystonia patient.