What is Prader-Willi syndrome?

Prader-Willi syndrome (PWS) is a rare genetic condition. It is caused by problems with the genes on chromosome 15. This usually happens by chance.

Although there is no cure for PWS, early treatment help with symptoms.

What are the symptoms of Prader-Willi syndrome?

In babies and young children, signs of PWS can include:

• a weak cry
• difficulty sucking to feed
• low muscle tone (floppiness)
• sleeping more than normal

Older children, teenagers and adults may have other symptoms and signs.

Physical features of PWS can include:

• being short for your age
• small hands and feet
• small genitals
• distinctive facial features (including a high and narrow forehead, a thin upper lip and downturned mouth, almond-shaped eyes, and eyes that look in different directions)
• lighter skin and hair than other people in the family
• very flexible muscles
• scoliosis (curved spine) or other spinal problems

Other features can include:

• an insatiable (limitless) appetite from about 2 years of age
• food cravings and weight gain
• developmental delays, including speech problems and delayed social and emotional skills
• mild to moderate intellectual disability
• behavioural problems
• mental health problems

People with PWS tend to also have breathing and sleeping problems. Hormone problems are also common in people with PWS.

What causes Prader-Willi syndrome?

Prader-Willi syndrome is a genetic condition that usually happens by chance. Rarely, it is inherited from a parent.

PWS causes problems with your hypothalamus — a part of your brain that controls the release of hormones.

When should I see my doctor?

See your doctor if you are concerned about your baby or child, including any worries about their:

• feeding
• growth
• development

How is Prader-Willi syndrome diagnosed?

You doctor will ask about your symptoms. They will also do a physical examination to look for signs and features of PWS.

If PWS is suspected, genetic testing can be done to confirm the diagnosis. Some people are not diagnosed until they are in their 20s or 30s.

How is Prader-Willi syndrome treated?

Ideally, people with PWS will receive treatment and support from a whole team of health professionals. These may include a:

• paediatrician (specialist in child medicine)
• endocrinologist (specialist hormone doctor)
• dietitian
• physiotherapist
• occupational therapist
• speech therapist
• psychologist

Diagnosing PWS as early as possible allows treatments that can help significantly with some of the symptoms.

Hormonal treatments

Early treatment with growth hormone can:

• improve height
• help prevent obesity
• improve physical and intellectual development
• change the typical facial appearance of people with PWS

Other hormonal treatments may also be recommended.

Feeding and weight management

Babies with PWS often need special feeding methods to gain weight.

Older children and adults with PWS usually cannot control their appetite because their brain doesn’t tell them when they have had enough to eat.

Weight management is needed to help control eating and weight.

Weight control can help reduce obesity-related complications.

Can Prader-Willi syndrome be prevented?

Genetic counselling may be recommended for some people to find out their chance of having a child with Prader-Willi syndrome.

Complications of Prader-Willi syndrome

Overeating and obesity are the most common complications of PWS.

Adults with PWS are at risk of developing serious health problems linked with obesity, such as:

• type 2 diabetes
• heart disease
• sleep apnoea

There can also be complications due to hormonal problems, including:

• infertility
• osteoporosis (a condition that makes your bones more likely to break)

Resources and support

Support for people with Prader-Willi syndrome and their families is available from Prader-Willi Syndrome Australia.

Visit healthdirect's genetic disorders guide to learn more about genes, types of genetic disorders and where to go for help and more information.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.