This causes an alteration in gene expression that disturbs various endocrinal processes like gonadotropin secretion and receptivity, ovarian steroidogenesis, insulin activity, and regulation of adipokines, which in turn causes demonstration of clinical manifestations like ovulatory dysfunction, disrupted folliculogenesis, polycystic ovarian morphology, hyperandrogenism, hyperinsulinemia, obesity that are associated with PCOS (Fig. 2). This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.