MAGEL2 and Prader-Willi syndrome: This is observed in mouse KO models of the imprinted Magel2 gene that map to the Prader Willi syndrome (PWS) region, recapitulating some features of PWS patients, who after a failure to thrive as young infants exhibit a catch-up phase leading to overweight and hyperphagia (Bischof et al., 2007).