INS and obesity due to melanocortin 4 receptor deficiency: SCD1 is a key regulator in lipid metabolism; high expression of SCD1 protein correlates with obesity, diabetes, and atherosclerosis and inactivation of SCD1 supports an HFD-resistant phenotype, reduced fat accumulation and insulin sensitivity (Flowers et al., 2007; Ralston et al., 2016; Dragos et al., 2017; Piccinin et al., 2019; Weiss-Hersh et al., 2020).