The DYT1 gene on human chromosome 9q34 appears to be responsible for most cases of early
onset primary torsion dystonia (PTD) both in Ashkenazi Jewish (AJ) and in non-Jewish patients.
Previous haplotype analysis in a 2 cM region surrounding the DYT1 gene showed that a single
founder mutation (DYT1AJ) was responsible for most cases of early onset PTD in the North
American AJ population and refined the most likely location of the gene to a 150 kb interval between
the marker loci D9S2161 and D9S63.
Recently, the majority of cases of early onset PTD in both AJ and non-Jewish patients were found
to carry a unique 3-bp (GAG) deletion in the coding region of the DYT1 gene. This deletion appears
to have arisen more than once, suggesting independent mutational events.
In this study, we analysed the haplotypes surrounding DYT1 in 9 AJ and 15 non-Jewish British
patients carrying the GAG deletion in the DYT1 gene. We found that all AJ British patients carried
the same haplotype as the North American Jews, sustaining the theory that the current British AJ
community descends from the same small group of individuals as the North American Jewry.
Furthermore, in the non-Jewish British patients, only a limited number of distinct founder
mutations was observed. This supports the hypothesis that the GAG deletion in the DYT1 gene is
not a very frequent mutation, and that it has arisen only a limited number of times throughout the