UCP3 and obesity due to melanocortin 4 receptor deficiency: More importantly, the association between UCP3 variants and HOMA-IR was found for 4 UCP3 SNP variants, namely rs647126, rs15763, rs3781907, and rs1685354, suggesting another important contribution to the UCP3 in obesity susceptibly due to insulin resistance and, consequently, higher blood sugar levels, that, in turn, it is a well stablished risk for T2DM.