Notably, the fat mass and obesity-associated (FTO) gene, which encodes an m6A demethylase, has been strongly associated with obesity and metabolic disorders in genome-wide association studies (GWAS) (Huang et al. 2023a; Azzam et al. 2022; Ran et al. 2020). Here, FTO is linked to obesity due to melanocortin 4 receptor deficiency.