PWS is a rare genetic condition that affects a child’s metabolism which changes their body and behaviour. This will cause a tremendous appetite that develops between 2 and 6 years of age, which can lead to obesity. PWS can also cause a delay in milestones and puberty. In the U.S, PWS affects ~1 in 10,000 to 30,000 people.

The cause of PWS is a loss of function in chromosome 15. There are many reasons why this may happen, this includes chromosomal deletion (nearly 70% of cases), maternal uniparental disomy (nearly 25% of cases), or translocation (less than 1% of cases).

Symptoms in infancy include a weak cry, lethargy (tiredness), poor feeding ability, and weak muscle tone. As children grow more symptoms may appear like almond shaped eyes, a long, narrow head, a triangular mouth, short height, small hands and feet, and underdeveloped genitals. They may experience some development and behavioural symptoms like emotional outbursts, sleep issues, problems with cognitive development, and not feel satisfied after eating large amounts of food.

Your doctor will start with asking questions about symptoms, including eating habits and behavior. If the doctor suspects PWS, they will run a genetic test.