Furthermore, constitutive activation of the mitotic signal MAPK-ERK1/2 has also been found in skeletal muscle biopsies of women with PCOS, which promotes serine phosphorylation of IRS1 and reduces metabolic signalling in PCOS myotube [77], suggesting that IR may impact both the metabolic and mitotic pathways in skeletal muscle of women with PCOS. The gene discussed is IRS1; the disease is polycystic ovary syndrome.