FTO and type 2 diabetes mellitus: Demethylase FTO is the first gene strongly associated with adipose mass and obesity in β-cells (Scuteri et al., 2007; Taneera et al., 2018), positively correlated with serum glucose (Blauth and Falliner, 1986), and closely associated with metabolic alterations, cardiovascular diseases, and T2DM (Boissel et al., 2009; Church et al., 2010; Lee et al., 2014).