Association of IL-16 gene polymorphisms with sporadic Parkinson's disease in a Han Chinese population.

This study was performed to investigate the genetic association of single-nucleotide polymorphisms (SNPs) in the interleukin-16 (IL-16) gene with the risk of Parkinson's disease (PD) in a Chinese Han population. Genotyping for the rs11556218 T/G, rs1131445 T/C and rs4072111 C/T polymorphisms of IL-16 was performed using the PCR-RFLP method in 405 patients with PD and 405 healthy matched individuals. Statistically significant difference for rs4072111 could be observed in both additive model (TC vs. CC: OR=0.622, 95 % CI: 0.443-0.873, P = 0.006) and dominant model (TC+TT vs. CC: OR =0.644, 95 % CI: 0.464-0.893, P = 0.008). The frequency of the rs4072111 T allele was significantly lower in the PD patients (OR= 0.692, 95 % CI: 0.515-0.929, P = 0.014) than in the controls. In subgroup analysis, a significant difference in genotype frequency distribution (P =0.004) and allele frequency (P =0.001) was found for rs4072111 between the male PD group and the control group, similar to the findings for the late-onset Parkinson's disease (LOPD) group and the control group (P = 0.044, 0.038, respectively). Conversely, there was no significant difference in the frequencies of rs11556218 and rs1131445 between the PD patients and controls. Moreover, seven common haplotypes were detected, and the CGT and CTC haplotypes were associated with PD susceptibility in our study. Our results indicate that the IL-16 gene rs4072111 polymorphism is significantly associated with PD susceptibility in the Chinese Han population but that the polymorphisms rs11556218 and rs4778889 are not.