FTO and obesity due to melanocortin 4 receptor deficiency: FTO is an obesity susceptibility gene and encodes 2-oxoglutarate and Fe (II)-dependent demethylase catalyzing the 3-methylthymine in single-stranded DNA and 3-methyluracil and 6-methyladenosine in RNA for repairing and modifying multiple nucleic acids (Loos and Yeo, 2014).