Other organs, such as the liver, predominantly express the PPARγ1 isoform, but can, under pathological conditions such as overnutrition and obesity, induce de novo the expression of the PPARγ2 isoform.8 This indicates that the types and relative amounts of PPARs coexisting in the same cell/tissue under specific physiological and pathophysiological conditions vary according to specific nutritional status and metabolic adaptations. This evidence concerns the gene PPARG and obesity due to melanocortin 4 receptor deficiency.