UCP2 and obesity due to melanocortin 4 receptor deficiency: These are the reasons why the roles played by UCP1-3826A/G, UCP2-866G/A, UCP2 Ala55Val, UCP2 Ins/Del and UCP3-55C/T polymorphisms in obesity risk and BMI changes have been extensively studied, although the results of these associations are still inconclusive (reviewed in [5], [6], [78]).