Association of polymorphisms of interleukin-18 gene promoter region with polycystic ovary syndrome in chinese population

Background: Recent research shows that polycystic ovary syndrome (PCOS) may have an association with low-grade chronic inflammation, and that PCOS may induce an increase in serum interleukin-18 (IL-18) levels. Methods: To investigate the polymorphisms of the IL-18 gene promoters with PCOS, two single nucleotide polymorphisms (SNPs) in the promoter of the IL-18 gene (at positions -607C/A and -137G/C) in 118 Chinese women with PCOS and 79 controls were evaluated using polymerase chain reaction (PCR). Results: No significant differences were found in the genotype distribution, allele frequency and haplotype frequency between the PCOS and control groups. Further analysis demonstrated a relationship between IL-18 gene promoter polymorphisms and PCOS insulin resistance (IR). Regarding the -137 allele frequency, G and C allele frequencies were 93.5% and 6.5%, respectively, in the PCOS with IR patients; G and C allele frequencies were 85.4% and 14.6%, respectively, in PCOS patients without IR (chi2 = 3.601, P = 0.048). Conclusions: The presence of a polymorphism in the IL-18 gene was found to have no correlation with the occurrence of PCOS. Carriage of the C allele at position -137 in the promoter of the IL-18 gene may play a protective role from the development of PCOS IR.