IGF1 and Prader-Willi syndrome: In view of existing information, GH dose based on ideal rather than actual body weight and monitoring serum IGF-1 levels between 0 and +2 SDS and/or IGF-1/IGFBP3 molar ratio without exceeding GH pretreatment should be considered to prevent abnormal serum IGF-1 elevation, insulin resistance, and occasional acromegaloid features seen in children with PWS at standard recommended GH dose.