FTO and obesity due to melanocortin 4 receptor deficiency: With regards to the possibility of pleiotropic effects by FTO or genes in high LD with FTO, we acknowledge that although FTO is one of the most well-studied obesity loci, and there are credible hypotheses for its action on adiposity by increasing the appetite [40],[41], the precise mechanism of the FTO polymorphisms is still unclear, and potential pleiotropy cannot completely be ruled out.