The most common polymorphisms studied in relation to MetS, T2DM, obesity, BMI, and lipid disorders were: –3826A/G (rs1800592), –112A/C (rs10011540), and –1766A/G (rs3811791) in the 5′-region, Ala64Thr (rs45539933) in exon 2, and Met229Leu (rs2270565) in exon 5 of the UCP1 gene. The gene discussed is UCP1; the disease is obesity due to melanocortin 4 receptor deficiency.