Haplotype analysis encompassing HTT gene in Chinese patients with Huntington's disease.

BACKGROUND AND PURPOSE: Huntington's disease (HD) is a dominantly inherited neurodegenerative disorder with varied prevalence in different populations, which may be associated with specific haplotypes. This study aims to explore the haplotypes encompassing HTT gene in the Chinese population.

METHODS: A total of 406 HD individuals and 59 normal relatives from 253 HD families were enrolled. Twenty-nine SNPs were selected and genotyped for the haplotype analysis.

RESULTS: In stage one, we used 18 tag SNPs (tSNPs) to replicate the distribution of three major haplogroups (A, B, C). We found that risk-associated haplogroup variants A1 and A2, enriched on Caucasian HD chromosomes, were totally absent from both Chinese HD and control chromosomes, and the distributions of haplogroups between HD and control chromosomes were similar. Therefore, in stage two, we used 29 tSNPs (including the18 tSNPs) to define new haplogroups (I, II, III) and found haplogroup I accounting for 61.3% on HD chromosomes while 34.4% on control chromosomes, indicating haplogroup I was enriched on Chinese HD chromosomes.

CONCLUSIONS: This is the first haplotype analysis encompassing HTT in the Chinese population. The results contribute to explaining the low prevalence of HD in China and provide a better understanding of genetic diversity in HTT region. This article is protected by copyright. All rights reserved.