Clinical studies reported FABP4 in the cultured medium of adipocytes had physiological activity, and that circulating levels of FABP4 were strongly linked with obesity and metabolic diseases [17-19], and had a significant role in type 2 diabetes and atherosclerosis by acting on metabolic and inflammatory pathways [30, 31]. Here, FABP4 is linked to obesity due to melanocortin 4 receptor deficiency.