Prader-Willi syndrome (PWS) was first described in 1956 by Swiss doctors, Prof. A Prader, Dr A Labhart and Dr H Willi, who recognised the condition as having unique and clearly definable features.
These features are, as medically described:-
• Hypotonia: weak muscle tone, and floppiness at birth.
• Hypogonadism: immature development of sexual organs and other sexual characteristics.
• Obesity: caused by excessive appetite and overeating (hyperphagia), and a decreased calorific requirement owing to low energy expenditure levels. (Obesity is not normally a feature of those whose food intake is strictly controlled.)
• Central nervous system and endocrine gland dysfunction: causing varying degrees of learning disability, short stature, hyperphagia, somnolence (excessive sleepiness), and poor emotional and social development.