Despite the large genetic pool that contributes to the development of obesity, this article only examines three genes commonly associated with obesity with a strong subsequent link to diabetes: the insulin-induced gene 2 (INSIG2), proprotein convertase subtilisin/kexin type 1 (PCKS1), and peroxisome proliferator-activated receptor gamma (PPARG) genes [31,32] (Figure 4). The gene discussed is PCSK1; the disease is obesity due to melanocortin 4 receptor deficiency.