Prader–Willi syndrome (PWS) is a complex neurobehavioral condition which has been
classically described as having two nutritional stages: poor feeding, frequently with failure to
thrive (FTT) in infancy (Stage 1), followed by hyperphagia leading to obesity in later
childhood (Stage 2). We have longitudinally followed the feeding behaviors of individuals
with PWS and found a much more gradual and complex progression of the nutritional
phases than the traditional two stages described in the literature. Therefore, this study …

Prader-Willi syndrome (PWS) is caused by a lack of expression of paternally-expressed
imprinted genes at human chromosome 15q11–13 and is characterized by a switch from
infant anorexia to childhood hyperphagia. A recent multiphase staging system recognizes
gradual changes between the anorexic and hyperphagic phases of PWS. We undertook to
use clinical records from an independent population to assess the multiphase system and
explore the implications for the evolution of distinctive features of human childhood. Medical …