The present findings may provide an explanation for the inconsistent data obtained in the previous studies (of populations with a different status of obesity) regarding the association between the UCP-1 gene A-3826G polymorphism and HDL-C, and may provide a hint about the different roles of the UCP-1 gene A-3826G polymorphism under obese and non-obese conditions. Here, UCP1 is linked to obesity due to melanocortin 4 receptor deficiency.