LEP and obesity due to melanocortin 4 receptor deficiency: Supporting this, it has been noted that upon ascent to altitude plasma levels of the “satiety hormone” leptin may increase immediately, followed by delayed falls in the “hunger hormone” ghrelin; it is also interesting to note in this regard that gestational hypoxia can disrupt the neonatal leptin surge in such a way that hyperphagia and obesity are programmed for adult life [162].