SIRT1, an NAD+ dependent type III deacetylase sirtuin, enhances glucose tolerance by potentiating brown adipose tissue function (Boutant et al., 2015) contributing to energy expenditure and browning of WAT and resistance to dietary obesity (Wang et al., 2013), interacts with PPARα and is required to activate PGC-1α (Purushotham et al., 2009). The gene discussed is SIRT1; the disease is obesity due to melanocortin 4 receptor deficiency.