Taking into account these preliminary observations, while patients suffering from essential morbid obesity might actually be treated with ghrelin receptor and CB1 neutral antagonists in order to block hyperphagia induced by palatable foods, the use of PYY agonists appears to be instead one of the most appropriate pharmacological strategy in PWS, allowing to reinforce the insufficient post-prandial anorexigenic response when PWS patients are exposed to palatable foods [31]. This evidence concerns the gene PYY and morbid obesity.