A bivariate meta-analysis of a large-scale genome-wide association study (GWAS) indicated three loci (2p23.2, 16q12.2, and 18q21.32) with pleiotropic effects on both obesity and OP, corresponding to the TRNA Methyltransferase 61B (TRMT61B), FTO, and Melanocortin 4 Receptor (MC4R) genes, respectively [5]. The gene discussed is MC4R; the disease is obesity due to melanocortin 4 receptor deficiency.