Members of the PPAR family, as well as GCM1 and its antagonist NFE2 have been implicated in human IUGR placentas (80–82), demonstrating that abnormal differentiation of the villous trophoblast, especially of the syncytiotrophoblast layer, also contributes to placental insufficiency and IUGR in humans. This evidence concerns the gene PPARA and fetal growth restriction.