INS and obesity due to melanocortin 4 receptor deficiency: In obesity and T2D, SSM is preferentially affected, observed as a reduced density and reduction in the electron transport chain activity and oxidative capacity (Ritov et al., 2005; Lionetti et al., 2007) Therefore, in the regulation of metabolism, SSM seems to be involved in fatty acid oxidation, glucose transport, propagation of insulin signaling, or other signaling cascades important to insulin action (Ritov et al., 2005).