In this regard, it is of interest to note that the selective ablation of SIRT6 from neurons in mice results in an adult-onset obesity (Schwer et al., 2010), while liver-specific deletion of Sirt6 in mice results in a “fatty liver” phenotype (Kim et al., 2010). The gene discussed is SIRT6; the disease is obesity due to melanocortin 4 receptor deficiency.