Prader-Willi syndrome

Also called PWS

Prader-Willi syndrome is a rare genetic condition caused by changes on chromosome 15. Babies often have floppy muscles and feeding problems. Later, children develop a constant desire to eat, which can lead to dangerous weight gain. It also causes learning difficulties, behavioural challenges and delayed puberty.

Last updated Nov 9, 2026

What it is

There is no cure, but early diagnosis and care make a big difference.

Care includes strict control of food access, growth hormone treatment, hormone therapy, exercise and support from a team of specialists.

Common signs

  • Floppy muscles and poor feeding in babies
  • Constant hunger from childhood
  • Rapid weight gain
  • Short height and small hands and feet
  • Learning difficulties
  • Behaviour problems such as temper outbursts

How it is usually diagnosed

  • A genetic blood test

Records worth keeping

Keeping these together makes each appointment easier, especially when you see a new doctor:

  • Genetic test results
  • Growth and weight charts
  • Endocrinology and dietitian letters
  • Education and care plans

Questions to ask your doctor

  • Would growth hormone help my child?
  • How can we manage food safely at home?
  • What support is available for our family?

When to get help right away

Call 112 or go to the nearest emergency department if you have:

  • A swollen, painful tummy or vomiting after eating a lot: call 112, as people with this condition may not show pain or fever

This page is general information. It is not a diagnosis and does not replace a doctor who knows your history. Medfold keeps your records organised; it does not interpret them.

Sources