LEP and obesity due to melanocortin 4 receptor deficiency: It is possible that in IUGR, the underlying mechanisms of inutero leptin action in the developing susceptibility to adult obesity are the alterations of the expression of appetite-stimulating neuropeptides such as NPY in the fetal brain.23 Adipocytokines, especially leptin, have been implicated in intrauterine growth, and unfriendly environments such as those related to IUGR may lead to upregulation in placental protein leptin synthesis as well as leptin mRNA in neonates with IUGR, as reported by ref. 24