FTO and obesity due to melanocortin 4 receptor deficiency: The fat mass and obesity associated gene (FTO), a m6A demethylase, has been linked to a variety of biological processes including dopaminergic neuron regulation [24] and a variety of human diseases including obesity, type 2 diabetes (T2DM), cancer, attention-deficit/hyperactivity disorder, and Alzheimer's disease [25–31].