FTO and obesity due to melanocortin 4 receptor deficiency: The fat mass and obesity-associated (FTO) gene is an AlkB-like, Fe(II)- and 2-oxoglutarate–dependent nucleic acid demethylase that has been shown to demethylate 3-methylthymine and 3-methyluracil in single-stranded DNA and RNA, respectively [1]–[2].