Association Between TAB2 Gene Polymorphisms and Susceptibility to Cryptorchidism in Han Chinese Population in Southwest China

  Objective   To conduct preliminary investigation into the correlation between transforming growth factor beta-activated protein kinase 1-binding protein 2 (TAB2) gene and the incidence of cryptorchidism in Han Chinese population in Southwest China.

  Methods  A total of 259 patients with cryptorchidism and 355 healthy controls from Southwest China were enrolled for the study. Polymerase chain reaction-restriction fragment length polymorphism method was used to analyze the genotype of the 3 tag single nucleotide polymorphisms (SNPs) of TAB2 gene, i.e., rs237028, rs521845 and rs652921. The Chi-square test was used to analyze the relationship between the genotype frequency of the three tag SNPs and the incidence of cryptorchidism.

  Results  The distribution of the 3 tag SNPs’ alleles and genotypes were in agreement with the Hardy-Weinberg equilibrium, and the genotype results of polymerase chain reaction-restriction fragment length polymorphism assay were consistent with those of Sanger sequencing. The frequency of the G allele at TAB 2 rs237028 was significantly higher in the cryptorchidism group than that in the control group (30.9% vs. 25.6%, P=0.04, OR=1.31, 95% CI: 1.01-1.70). In the dominant model, the risk of cryptorchidism was significantly higher in AG/GG genotype carriers (P=0.006, OR=1.57, 95% CI: 1.14-2.17). In the cryptorchidism group, the TC/CC genotype frequency of the rs652921 locus were significantly higher than that of the control group (75.3% vs. 67.0%, P=0.03, OR=1.50, 95% CI: 1.05-2.14). Correlation between rs521845 and susceptibility to cryptorchidism was not observed in the Han Chinese population.

  Conclusion  The AG/GG genotype of rs237028 locus and the TC/CC genotype of rs652921 locus of the TAB2 gene may be associated with increased risks of cryptorchidism in Han Chinese population in southwest China.