Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a rare genetic condition that affects growth and development.

Key points

  • PWS is caused by a genetic defect on chromosome number 15. This happens by chance and is not passed down in families. Why it happens is unknown.
  • People with PWS are shorter than usual, have a constant desire to eat, and have cognitive (thinking) and behavioural difficulties.
  • Around one in 10,000 to 20,000 children are born with the syndrome.
  • It’s not a life-threatening condition; however, the weight gain from uncontrolled eating can lead to serious health issues, such as obesity and diabetes.
  • With support from health professionals, people with PWS can lead healthy fulfilling lives.

What causes Prader-Willi syndrome?

PWS occurs when several genes on chromosome 15 are deleted or not expressed. This affects the part of the brain (the hypothalamus) that regulates hormones and appetite, as well as the development of muscle tone and expression of emotions. 

What are the symptoms of Prader-Willi syndrome?

Babies with PWS tend to be floppy and have trouble sucking. By about two years old, they tend to be short for their age, with small hands and feet, and their desire to eat all the time is present. There may be signs of delays with learning to walk and talk, and with difficulties cognition (thinking) and behaviour, such as temper tantrums and stubbornness.

PWS can cause other problems, such as obesity due to over-eating, osteoporosis, sleep and breathing issues and lack of sexual development.

How is Prader-Willi syndrome diagnosed?

If your child has symptoms of PWS, talk to your doctor. If your doctor suspects your child has PSW, they will recommend a genetic test be carried out, which will confirm whether or not they have it.

What is the treatment for Prader-Willi syndrome?

As PWS has no cure, treatment is aimed at managing symptoms and the problems associated with this condition. This includes:

  • strict supervision of your child’s diet
  • exercise to build muscle mass
  • managing their behaviour.

Growth hormone treatment may be an option. This may lead to cognitive and other benefits as well.

Most people with PWS will need specialised care and support from a team of health professionals throughout their lives.

How can I care for myself when looking after someone with Prader-Willi syndrome?

It’s important that you get support for yourself (see the support options below). Remember to take care of your own needs for sleep, exercise, healthy eating and time for yourself.

Counselling provides extra support. Talk to your doctor for a recommendation or find a counsellor here

Following the advice of health professionals in caring for your family member with PWS will make it easier for you and them. This includes keeping food out of sight, sticking to a routine and being clear and firm in your instructions.


Prader-Willi Syndrome Association New Zealand Freephone 0800 4 PWS HELP
Disability services funded by the Ministry of Health New Zealand 

Learn more

Prader-Willi Syndrome NHS Choices, UK, 2014
Prader-Willi Syndrome Association Australia
International Prader-Willi Syndrome Association


  1. Prader-Willi Syndrome Better Health Channel, Australia, 2014
  2. Prader-Willi Syndrome Association Australia Australia, 2017
  3. Human Growth Hormone Treatment for Prader-Willi Syndrome in Adolescent and Adult Patients: Clinical Evidence, Safety, and Guidelines Canadian Agency for Drugs and Technologies in Health, 2015
  4. Cognitive and adaptive advantages of growth hormone treatment in children with Prader-Willi syndrome Dykens EM, Roof E, Hunt-Hawkins H. J Child Psychol Psyc. 2017 Jan;58 (1): 64–74. 
Credits: Health Navigator Editorial Team.