Moreover, Yuan et al. demonstrated that the PPARα-dependent Fgf21 demethylation occurs in the liver during the postnatal period, also, they propose that Fgf21 methylation, as a form of epigenetic memory, could persist into adulthood and play a key role in the developmental progress of obesity (56). This evidence concerns the gene FGF21 and obesity due to melanocortin 4 receptor deficiency.