BCAT2 and obesity due to melanocortin 4 receptor deficiency: Branched-chain amino acids (BCAAs) are associated with the progression of obesity-related metabolic disorders [23]; additionally, BCAA catabolism is suggested to play a role in the pathogenesis of metabolic disturbances, and BCAT2 is an important enzyme that catalyzes the initial step of BCAA catabolism [24,25].