SORL1 and obesity due to melanocortin 4 receptor deficiency: Interestingly, obesity and caloric intake in Type 2 diabetes mellitus patients with morbid obesity and cognitive decline enhance SORL1 expression in peripheral mononuclear cells of plasma, together with other AD-related genes such as APP, PSEN2, ADAM9, and GSK3β. Such expression profile is reduced after gastric bypass surgery [212] or diet [212, 213].