Association of an oestrogen receptor gene polymorphism in Chinese Han women with endometriosis and endometriosis-related infertility.

Endometriosis is a steroid-dependent complex disease. The oestrogen receptor plays an important role by mediating oestrogen action and eutopic or ectopic endometrium development. This study investigated whether single-nucleotide polymorphisms in the genes for oestrogen receptor 1 (ESR1) and oestrogen receptor 2 (ESR2) are associated with endometriosis and endometriosis-related infertility. The participants included 157 infertile and 155 fertile endometriosis women as well as 92 women with primary infertility and 265 fertile women as controls. The iPLEX Gold system (MassARRAY system, Sequenom) was used for genotyping of ESR1 and ESR2. Statistical analysis showed that ESR1 (rs3798573 A/G) was significantly associated with endometriosis and endometriosis-related infertility (P=0.011, P=0.009). No association was found with ESR1 (rs1159327 A/G, rs3020348 A/C) and ESR2 (rs17179740 A/G) either for endometriosis or endometriosis-related infertility. According to the revised American Fertility Society classification, all of the detected single-nucleotide polymorphisms had no association with endometriosis in stage I-II or in stage III-IV. The results suggest that the ESR1 polymorphism rs3798573 A/G is associated with increased risk of endometriosis and endometriosis-related infertility in Han women from central China. Endometriosis is an oestrogen-dependent complex disease, which is one of the most common causes of infertility. Oestrogen receptors (ESR), which mediate oestrogen actions, are considered to play an essential role in the pathogenesis of endometriosis. Therefore, ESR may also play an important role in endometriosis-related infertility. To investigate the association between ESR and endometriosis or endometriosis-related infertility, detection of ESR polymorphisms have been carried out in several populations by other researchers; however, the results remain controversial. In a previous study of ours, through a pooling-based genome-wide scan of endometriosis and controls, we obtained two highly ranked single-nucleotide polymorphisms (SNP) that were individually located in introns of the genes ESR1 and ESR2. To find more evidence of a relationship between ESR and endometriosis or endometriosis-related infertility, the current study selected for genotyping another two ESR1 SNP from a Japanese genome-wide association study in endometriosis. According to the genotypes and the patients' histories, we found that the ESR1 polymorphism rs3798573 A/G was associated with risk of endometriosis and infertile endometriosis in Han women from central China. Crown