Thiazolidinediones (TZDs), commonly used for such treatment, act as full agonists of the peroxisome proliferator-activated receptor gamma (PPARγ) [6–8], which is involved in the pathophysiology of various diseases apart from T2DM and obesity, including dyslipidemia, atherosclerosis, neoplasia and tumors, inflammatory disorders, and neurodegenerative diseases [9–11]. The gene discussed is PPARG; the disease is obesity due to melanocortin 4 receptor deficiency.