PPARG and obesity due to melanocortin 4 receptor deficiency: The results of multi-omics analyses showed NAFLD was improved by the serine hydroxy methyltransferase 2/glycine/mammalian target of rapamycin/peroxisome proliferator-activated receptor gamma (SHMT2/glycine/mTOR/PPAR-γ) signalling pathway, with the increasing contents of glutathione, total antioxidant capacity, and adiponectin, which may improve oxidative stress, inhibit lipid peroxidation, and reduce the risk of obesity metabolic abnormalities.