MC4R and obesity due to melanocortin 4 receptor deficiency: Consequently, we conducted the present research in Caucasian children with obesity to perform an association study of individual and multi-locus combinations (haplotypes) of the genetic variants rs17782313 (T>C), rs17773430 (T>C), and rs34114122 (A>C) of the MC4R gene (Figure 1) and potential interactions between these polymorphisms and metabolic risk factors.