Assessment of D216H DYT1 polymorphism in a Chinese primary dystonia patient cohort

Background: The D216H single‐nucleotide polymorphism (SNP) (rs1801968) in DYT1 exon 4 has been suggested to be a genetic modifier in primary dystonia. Methods: To further explore this question, we assessed rs1801968 variations in a cohort of 210 Chinese patients with primary dystonia devoid of DYT1 mutations. Results: We found that focal dystonia, specifically cervical dystonia, was the most common form of dystonia, with 8.1% of all the patients having a positive family history of dystonia. No association of the D216H SNP with primary dystonia was identified. In a subsequent subgroup analysis, the 216H allele was found to occur more frequently in patients with writer’s cramp, but no correlation was found between the allele and other forms of dystonia or age of onset. Conclusions: Our findings do not confirm that the allele contributes to the risk of D216H SNP primary dystonia.