Several studies have demonstrated that insulin receptor, insulin receptor substrate 1 (IRS1) and kinase activities are decrease in the muscles of early-T2D patients (Goodyear et al. 1995; Caro et al. 1987), suggesting that insulin receptor and IRS1 play important roles in the insulin signalling pathway (Hepp 1980). The gene discussed is INSR; the disease is type 2 diabetes mellitus.