It was previously demonstrated that the genetic effects of variants associated with either insulin secretion (like for GCK, KCNJ11 or TCF7L2) or insulin action (for ENPP1, ADIPOQ or PPARG) may be modulated by the obesity status or adiposity [9,12,26,28,32,34]. This evidence concerns the gene KCNJ11 and obesity due to melanocortin 4 receptor deficiency.