ESR2 and polycystic ovary syndrome: To help address this discordance related to PCOS genetic association studies, we focused our research on SNVs in genes encoding proteins important in the HHO axis, namely GNRHR (rs104893837), oestrogen receptor 2 (ESR2 rs4986938), luteinising hormone/choriogonadotropin receptor (LHCGR rs2293275) and follicle-stimulating hormone receptor (FSHR rs6166, rs6165, rs2349415).