The commonly observed UCP2 gene single nucleotide polymorphisms (SNPs) G(−866)A in the promoter region (rs659366) and Ala55Val (a C to T substitution) in exon 4 (rs660339) have been associated with obesity and T2DM to a certain degree. The gene discussed is UCP2; the disease is obesity due to melanocortin 4 receptor deficiency.