UCP1 and obesity due to melanocortin 4 receptor deficiency: Several studies have reported that polymorphisms of the UCP1 gene such as, g.-3826A > G (rs1800592), g.-1766A > G (rs10011540) and g.-112A > C (rs3811791) in the promoter region, and p.Ala64Thr (rs45539933) and p.Met299Leu (rs2270565) in the codon region are associated with obesity and T2DM [10–15].