Growth and differentiation factor 15 (GDF-15) is a cytokine of the transforming growth factor beta (TGF-β) family that has been increasingly studied for its relationship with several physiological and pathological processes, including stress-induced inflammation, cardiovascular diseases, kidney diseases, and obesity, probably in a counterregulatory way (13-17). The gene discussed is GDF15; the disease is obesity due to melanocortin 4 receptor deficiency.