DYT1 mutations amongst adult primary dystonia patients in Singapore with review of literature comparing East and West

Abstract

Background Dystonia is a heterogenous group of movement disorders whose clinical spectrum is very wide. At least 13 different genes and gene loci have been reported. While a 3-bp deletion in the DYT1 gene is the most frequent cause of early limb-onset, generalized dystonia, it has also been found in non-generalized forms of sporadic dystonia. An 18-bp deletion in the DYT1 gene has also been reported. Objectives We screened for the 3-bp and 18-bp deletions in the DYT1 gene among our sporadic, adult-onset primary dystonia patients in Singapore. We reviewed the literature to compare the frequency of DYT1 mutation between the East and the West. Methods We screened 54 patients with primary dystonia (focal: n = 41; segmental: n = 11; multifocal: n = 1; generalized: n = 1) for the deletions in the DYT1 gene. A careful review of all published literature on DYT1 screening among sporadic, non-familial, non-Ashkenazi Jewish patients was done. Results We did not detect any mutations in the exon 5 of the DYT1 gene in any of our patients. The frequency of DYT1 mutation amongst Asians (1.0%) was comparable to the West (1.56%) ( p = NS). Conclusions DYT1 mutations are uncommon amongst adult primary dystonia patients in Singapore.