PURPOSE: The objective of this study was to elucidate the relationship between two single nucleotide polymorphisms (SNPs) rs7176005 and rs6493497 in CYP19 gene and the risk of polycystic ovary syndrome (PCOS) in Northern Chinese women. METHODS: In this case-control study, a total of 340 women with PCOS and 340 matched healthy controls were recruited. Polymerase chain reaction ligase detection reaction (PCR-LDR) method was used to investigate two SNPs (rs7176005 and rs6493497) in the 5'-flanking region of CYP19 gene exon 1. RESULTS: We observed a significant association of rs7176005 and rs6493497 with reduced risk of PCOS. Compared with CC genotype, a significant association of CT genotype (p = 0.019), TT genotype (p <
0.001) and combined CT + TT genotype (p <
0.001) with reduced risk of PCOS was observed. The result of linkage disequilibrium analysis showed that these two SNPs are in complete linkage disequilibrium (r CONCLUSIONS: These findings highlight a significant association between CYP19 gene polymorphisms and PCOS susceptibility, implying potential protective effects of T and A alleles. Of course, the major limitation of this study is the sample size of the case-control study. Larger cohort studies are needed to confirm these findings and investigate the underlying causes.