In the past four years, many genetic loci have been implicated for BMI from the outcomes of genome-wide association studies (GWAS), primarily in adults. Insulin-induced gene 2 (INSIG2) was the first locus to be reported by this method to have a role in obesity but replication attempts have yielded inconsistent outcomes. The identification of the second locus, the fat mass- and obesity-associated gene (FTO), h has been more robustly observed by others. Studies from both FTO knock out and FTO overexpression mouse model support the fact that FTO is directly involved in the regulation of energy...