Serum ghrelin levels are inversely correlated with body mass index, age, and insulin concentrations in normal children and are markedly increased in Prader-Willi Syndrome. - Haqq,AM.; Farooqi,IS.; O’Rahilly,S.; Stadler,DD.; Rosenfeld,RG.; Pratt,KL.; LaFranchi,SH.; Purnell,JQ. (J Clin Endocrinol Metab, 2003)