ESR2 and polycystic ovary syndrome: Related studies have been conducted on at least 70 genes, which roles are involved in the main process of this disease, such as steroid synthesis (CYP11A1 and CYP19A1) (15), steroid action (ESR1, ESR2, and PGR) (16), lipid metabolism (PPARG and MTHFR) (17–19), insulin action (HMGA2) (20) and embryonic development (SUMO1P1) (21, 22) have been implicated in PCOS.