Histone H3K9 is a major target of SIRT1, which belongs to the NAD + -dependent class III deacetylase sirtuin family and plays an important role in the regulation of lipid and glucose metabolism associated with nutritional and hormonal signaling [18] and therefore influences the development and progression of various metabolic disorders such as NAFLD and obesity [19]. Here, SIRT1 is linked to obesity due to melanocortin 4 receptor deficiency.