Association of IL-1α rs17561 and IL-1 RN rs315952 polymorphisms with Tourette syndrome: a family-based study.

Aim: Immune system dysregulation has been implicated to play a key role in pathogenesis of Tourette syndrome (TS). IL-1α and IL-1RN are important inflammatory cytokines that mediate the inflammation. In this study, we investigated the relationship between single-nucleotide polymorphisms (SNPs) of IL-1α and IL-1RN and the susceptibility to TS in Chinese Han population.

Methods: A total of 276 children with TS and their parents were recruited in the study. All DNA from our subjects were genotyped for SNPs of IL-1α rs17561 and IL-1RN rs315952 using predesigned TaqMan SNP genotyping assay. The genetic contributions of two polymorphisms were evaluated using transmission disequilibrium test (TDT) and haplotype relative risk (HRR) design. In addition, to increase the efficiency of the test, the haplotype-based HRR (HHRR) was performed.

Results: No significant differences were observed in allelic and genotypic frequency of rs17561 in IL-1α and rs315952 in IL-1RN between the transmitted group and non-transmitted group (for IL-1α rs17561: TDT=0.890, df=1, P=0.402; HRR=1.011, X(2)=3.016, P=0.082, 95% CI=0.999-1.024; for IL-1RN rs315952: TDT=0.095, df=1, P=0.805; HRR=0.984, X(2)=0.008, P=0.929, 95% CI=0.695-1.394). Similarly, the analysis of HHRR also did not support a significant association (for IL-1α rs17561: HHRR=1.226, X(2)=0.915, P=0.339, 95% CI=0.807-1.863; for IL-1RN rs315952: HHRR=0.963, X(2)=0.094, P=0.759, 95% CI=0.758-1.225).

Conclusion: Our results suggest that IL-1α rs17561 and IL-1RN rs315952 polymorphisms may not be associated with susceptibility to TS in Chinese Han population. However, the results still need to be replicated in a larger sample size and different populations.