Lack of genetic association of 5-HTR2A 102 T/C and -1438A/G polymorphisms with Tourette syndrome in a family-based association study in a Chinese Han population.

INTRODUCTION: Our purpose is to investigate whether polymorphisms of 102 T/C and -1438A/G in 5HTR2A are associated with Tourette syndrome (TS) in Chinese Han population.

METHODS: A total of 178 TS trios were recruited in this study. After the allelic and genotypic distributions of two polymorphisms were genotyped using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP), we compared their genetic distributions with what is expected with Hardy-Weinberg to explore whether there might be an association of these polymorphisms with TS by haplotype relative risk (HRR) and transmission disequilibrium test (TDT) statistics.

RESULTS: Our results showed that no significant associations were found between the HTR2A 102 T/C and -1438A/G polymorphisms and TS (for HTR2A 102 T/C: TDT = 2.041, df = 1, P = 0.175; HRR = 1.468, χ(2)  = 1.905, P = 0.168, 95% confidence interval: 0.850-2.535; for HTR2A: -1438A/G, TDT = 0.093, df = 1, P = 0.819; HRR = 0.965, χ(2)  = 0.018, P = 0.894, 95% confidence interval: 0.574-1.624).

DISCUSSION: Our study suggested that the HTR2A 102T/C and -1438A/G polymorphisms may not be associated with susceptibility to TS, and thus do not play a major role in the development of TS in the Chinese Han population. However, these results need to be confirmed in a larger sample collected from different populations.