SCD and obesity due to melanocortin 4 receptor deficiency: A plethora of previous studies have established SCD1 as a key regulator in lipid metabolism; high expression of SCD1 protein correlates with obesity, diabetes, and atherosclerosis, while inactivation of the Scd1 gene supports an HFD-resistant phenotype, reduced fat accumulation, and insulin sensitivity (Ntambi et al., 2002; Flowers et al., 2007; Dobrzyn et al., 2008; Liu et al., 2010).