PWS is characterised by its nutritional phases from initial feeding difficulties and failure-to-thrive in infancy, to progressive hyperphagia and morbid obesity (if access to food is not controlled) from later childhood to adulthood, growth hormone (GH) and sex hormone deficiencies, secondary to hypothalamic dysfunction (Miller et al., 2007; Goldstone et al., 2008; Goldstone et al., 2012), and possible pro-hormone/−neuropeptide precursor processing defects (Burnett et al., 2017). This evidence concerns the gene GH1 and Failure to thrive.