Genetic Association Between IL-21 Polymorphisms and Cryptorchidism in a Chinese Han Population

Abstract

Increasing evidence suggests an association between interleukin gene polymorphisms and cryptorchidism. To investigate the relationship between IL-21 gene polymorphisms and cryptorchidism susceptibility, a comprehensive genetic association study in a Chinese Han population was conducted. A total of 328 men were enrolled in a case-control study (116 cases and 212 healthy controls). Three SNPs (rs907715, rs2055979, and rs12508721) of the IL-21 gene were genotyped using the TaqMan(®) genotyping assay. For the rs2055979 C>A polymorphism, A allele carriers had significantly decreased cryptorchidism susceptibility (p = 0.021, odds ratios [OR] = 0.58, 95% confidence intervals [CI] = 0.37-0.93) in a dominant model (AA+CA vs. CC), a codominant model (AC vs. CC; p = 0.029, OR = 0.52, 95% CI = 0.31-0.85), and an overdominant model (AC vs. CC/AA; p = 0.0087, OR = 0.53, 95% CI = 0.33-0.86). However, no associations were identified for the rs907715 C>T and rs12508721 C>A polymorphisms. In the haplotype analyses, the C-C-T haplotype of rs907715-rs2055979-rs12508721 significantly increased the risk of cryptorchidism (p < 0.0001, OR = 5.251, 95% CI = 2.528-10.906). The rs2055979 C>A polymorphism of the IL-21 gene is associated with cryptorchidism susceptibility, and the C allele increases the risk of cryptorchidism in a Chinese Han population.