GPT and obesity due to melanocortin 4 receptor deficiency: After 33 weeks of high-fat diet (HFD), the wild-type C57BL/6 (Wt) mice developed obesity (Supplementary Fig. 1A), severe hepatic steatosis (Supplementary Fig. 1B,C) and hepatic injury as assessed by ALT activity (Supplementary Fig. 1D).