INS and obesity due to melanocortin 4 receptor deficiency: For example, adipocytokines such as leptin and adiponectin, which are able to regulate and affect insulin sensitivity through modulation of insulin signaling and the molecules involved in glucose and lipid metabolism, are deregulated in a very similar way in both psoriasis and obesity, highlighting the mechanisms of the possible common association with IR observed in those patients (e.g., plasma levels of adiponectin are decreased in obesity, psoriasis, IR, and type 2 diabetes) [68–71].