Given the key clinical features of PCOS, initial candidate genes included those implicated in steroidogenesis (e.g. CYP11A1, CYP17A1, STAR), androgen and gonadotropin signaling (e.g. FSHR, LHCGR, SHBG, AR), and insulin resistance (e.g. INSR, INS-VNTR, IGF1, IGF1R, IRS1, PPARG), among others (Urbanek et al. 1999). This evidence concerns the gene INSR and polycystic ovary syndrome.