Interestingly, there are data indicating that PPAR/RXR heterodimers are capable of binding to estrogen response elements (EREs), and PPAR and estrogen receptors (ERs) share cofactors [24–28], suggesting that signal cross-talk may exist between PPARα and ERs in the control of obesity. Here, PPARA is linked to obesity due to melanocortin 4 receptor deficiency.