LEP and Prader-Willi syndrome: In a PWS mouse model, a progressive central leptin insensitivity has been observed and it predicted the reduction in the anorexic leptin-mediated effect and the energy expenditure, likely through the impairment of the activation of leptin-responsive pro-opiomelanocortin neurons and the release of the melanocortin receptor agonist α-melanocyte-stimulating hormone [12].