Prader-Willi syndrome


There's no cure for Prader-Willi syndrome (PWS), but a team of different healthcare professionals will help you manage any problems your child has due to the syndrome, such as overeating, and treat any associated conditions.

A care plan will be drawn up to address your child's problems and needs. The plan will be continually reassessed as your child gets older and their needs change.

You and your child will also be given a key worker who will be your point of contact for the various support services available. While your child is young, it's likely the key worker will be a health visitor. As your child gets older and their needs become more complex, it's likely the key worker will be a social worker.

Most adults with Prader-Willi syndrome are unable to live fully independent lives, such as having a full-time job and living in their own home. Their behavioural issues and problems with food mean these environments and situations are too demanding. Adults with the syndrome who don't live with their parents will probably require residential care.

Below is a guide to managing the various problems and symptoms commonly seen in babies, children and teenagers with Prader-Willi syndrome.

Treating problems in babies

Poor feeding

Problems with sucking mean babies with Prader-Willi syndrome have difficulty feeding and don't gain as much weight as they should during their first year of life.

Your baby will probably need to be fed using a tube that goes into their nose and down their throat into their stomach.

After a few months, it'll usually be possible to feed your child normally using breast or bottle milk. You can use several techniques to encourage your baby to feed:

  • Hold your baby on your lap so both your hands are free. Use one hand to hold the nipple or bottle teat and the other hand to help close your baby's lips.
  • Before introducing the teat or nipple into your baby's mouth, stimulate their mouth by gently tapping or stroking their tongue, lips and cheeks.
  • If you're breastfeeding, you could place a bottle teat over your nipple. This will allow you to help your baby suck by placing pressure on the teat.
  • You can encourage your baby's sucking reflex by placing your finger on their cheeks and gently stroking towards their lips. Once your baby begins to suck gently, pull back the nipple or teat to encourage them to hold on.
  • If your baby is having difficulty swallowing, stroke under their chin down to the top of their breastbone in a downward movement.

Several bottles are available that can make feeding easier. They're designed for children with a cleft lip or palate (a birth defect that affects the mouth), but are also useful for babies with Prader-Willi syndrome. See the Cleft Lip and Palate Association (CLAPA) for more information.

Undescended testicles

If you have a baby boy with undescended testicles, surgery is usually recommended to correct this in the first or second year of life.

Treatment is recommended for two reasons:

  • your son will have an increased risk of developing testicular cancer if the testicle isn't corrected
  • your son may have problems with his self-esteem and body image if he is 'missing' one or both testicles

Read more information about treating undescended testicles.

Managing weight and diet

Trying to get your child to stick to a healthy diet and maintain a normal weight is one of the most important aspects of caring for a child with Prader-Willi syndrome. It's also probably one of the most challenging and frustrating.

If your child wants to eat frequently, most of the food they eat should be low in calories. A recommended daily diet plan usually looks like this:

  • six to eight servings of vegetables a day – one serving is around half a cup of raw vegetables or one cup of cooked vegetables
  • three to five servings of bread, cereal, rice or pasta a day – one serving is one slice of bread, or half a cup or 28g (1oz) of rice or pasta 
  • four servings of fruit a day – one serving is around half a cup of canned or fresh fruit, quarter of a cup of dried fruit, or half a cup of fruit juice
  • two servings of milk, cheese or yoghurt a day – one serving is around one cup of milk, 30g (1oz) of cheese or half a cup of sugar-free and fat-free yoghurt 
  • one to two servings of meat, poultry, fish, eggs or dried beans a day  – one serving is 60g (2oz) of cooked lean meat, fish or poultry, one egg, or half a cup of cooked dried beans

Restrict your child's access to sweets and fatty foods as much as possible.

Your care team will be able to give you a more detailed diet plan that's individually tailored to your child.

Getting your child to stick to the plan voluntarily is practically impossible, so you'll probably need to restrict your child's access to food. You can do this by:

  • locking any storage areas that contain food, such as your fridge or cupboards (children with Prader-Willi syndrome have been known to eat food out of the bin or freezer, so you may need to restrict access to these too)
  • regularly searching your child's room for hidden food
  • not allowing your child to leave the house unsupervised
  • not leaving your child unsupervised with other children who are eating, in case they try to steal other children's food

It's also important to let relatives, friends, other parents and teachers know about the need to restrict your child's diet.

Some medications have been used to try to suppress children's appetites but they've all been unsuccessful.

Weight-loss surgery isn't recommended for children with Prader-Willi syndrome because they don't have the willpower to stick to the strict diet required after surgery.


Exercise plays an important part in helping your child maintain a healthy weight. Children should do at least 60 minutes of exercise a day.

Many children with Prader-Willi syndrome have reduced energy levels. Therefore, it may be a good idea to break down their exercise into five to 10-minute sessions throughout the day to stop them getting tired and discouraged. Your child's care team should be able to recommend a suitable exercise plan.

Children with Prader-Willi syndrome usually prefer individual activities to team sports, such as:

It's important not to promise food as a reward to encourage your child to participate in exercise because it can encourage unhealthy behaviour.

Read more about physical activity guidelines for young people.

Hormone treatments

Treatment with an artificial version of the human growth hormone (HGH) is usually recommended for most children with Prader-Willi syndrome.

Routine NHS use of HGH for children with Prader-Willi syndrome only began in 2010, so it's difficult to know what effect treatment will have on adult height. Initial research suggests that HGH may help increase final adult growth by around 10.5cm (4.1 inches).

HGH also has a number of other important health benefits. For example, it:

  • increases muscle size while lowering the amount of body fat
  • should increase energy levels, which will help your child become more physically active
  • helps normalise facial appearance, making the distinctive facial features associated with Prader-Willi syndrome less noticeable

It's usually recommended that treatment with HGH begins during early childhood, at around two to four years of age, and lasts for up to four years.

A type of HGH called somatropin is used to treat children with Prader-Willi syndrome. Somatropin is given by daily injection using an auto-injector syringe. Most children tolerate somatropin well and side effects are uncommon.

It's usual to replace female sex hormones (often with the combined oral contraceptive pill) to encourage development of secondary sex characteristics (breast development) and periods, and also to improve bone strength and prevent osteoporosis.

Replacing male hormone (testosterone) is more contentious as although this will encourage development of puberty and build muscle strength it's possible that some behavioural problems will be exaggerated.

Managing behavioural problems in children

Structure and routine

Most children with Prader-Willi syndrome cope best if they have a very structured environment and daily routine. For example, you should:

  • establish a regular daily routine and give plenty of notice if any changes are planned
  • not put pressure on a child to speed up to complete a task – give them plenty of warning if they need to complete an activity, such as getting dressed to go out
  • ensure other people, such as relatives and teachers, are briefed about how to interact with your child
  • avoid eating in front of your child so they don't start to think about food

Dealing with tantrums

Parents often learn to recognise the warning signs of a temper tantrum. It's sometimes possible to stop the tantrum before it starts using a number of approaches. For example:

  • try to take their mind off the situation by doing or saying something unexpected, or talking about a subject they're interested in
  • encourage them to go to a quiet place for a few minutes and try some deep breathing or listen to soothing music
  • avoid saying things like, "You'd better not have a tantrum about this"
  • remain as cool and calm as possible – if you feel your child's frustration is directed at you, your partner or another carer can take over the situation

After a tantrum, try to remain as calm as possible. If your child hurts themselves or others, you may need to be taught special restraint techniques. Your child's care team will be able to advise you about this.

It's important not to give in to the demands that provoked the tantrums. While this may be tempting, it will signal to your child that tantrums are an effective way of getting what they want. 

Stealing food

Many children with Prader-Willi syndrome will try to steal food if they get the opportunity. This isn't because they're being naughty, it's because they aren't able to control their impulses when it comes to food. They're often unable to help themselves from stealing food.

Nevertheless, stealing food is a behavioural problem that needs to be addressed, otherwise your child could become severely obese.

Tips to prevent stealing food include:

  • Trying to establish a contract to reward good behaviour. In younger children, a verbal agreement, such as,"If you stick to your diet then you can play an extra hour with your puzzles", should be sufficient. In older children and teenagers, a written contract may be more appropriate, particularly as children with Prader-Willi syndrome respond well to clear instructions.
  • Most children with the syndrome will automatically lie about stealing food, even when the evidence is overwhelming. Rather than asking, "Did you steal that food?" say something along the lines of, "I know you stole that food and we need to talk about why that's wrong".
  • It's important your child understands the consequences of their actions and what's considered acceptable behaviour. If they steal food or money to buy food, always insist that they apologise and pay any money back.

Controlling the urge to steal food should always be highly praised and persistent good behaviour rewarded.

The Prader-Willi Syndrome Association have also produced a leaflet about Behaviour management in PWS (PDF, 144kb).

Treatment for skin picking

In Prader-Willi syndrome, frequent skin picking can lead to scarring and skin infections, such as cellulitis (an infection of the underlying tissue).

This may be a problem if it affects the legs. Reduced mobility and obesity reduce the drainage of blood from the legs, causing them to swell. This, along with diabetes, reduces the ability to fight skin infections, and skin picking introduces the bacteria that cause infection.

Once the skin has been damaged by cellulitis, it's susceptible to further infection. Therefore, it's very important for cellulitis to be identified early and for it to be treated with large doses of antibiotics.

It's recommended you keep your child's nails as short as possible. This should help minimise damage to the skin.

Keep any areas of damaged skin as clean as possible. If your child has a history of frequent skin infections, their care team may prescribe an antibiotic cream you can use on damaged areas of skin to prevent infection.

Two types of treatment that are moderately effective in helping prevent people with Prader-Willi syndrome from picking their skin are cognitive behavioural therapy (CBT) and medication.

Cognitive behavioural therapy

Cognitive behavioural therapy (CBT) is a type of talking therapy. It aims to change unhelpful and unhealthy patterns of behaviour by changing the way people think.

It's thought people with Prader-Willi syndrome pick their skin as a way of coping with situations such as feeling unhappy or bored. CBT can help people understand the thought patterns that drive skin picking and encourage them to find new ways of thinking about and coping with these situations.


Selective serotonin reuptake inhibitors (SSRIs), a type of antidepressant, or antipsychotics (medication usually used to treat psychosis) are sometimes recommended to treat Prader-Willi syndrome. However, these medications can cause side effects and are not usually recommended for children under the age of 18.

It's likely that prescribing medication will only be considered if the symptoms of skin picking are severe enough to justify the associated risks of treatment.

Treatment for psychosis

A small number of people with Prader-Willi syndrome develop psychosis, usually during the teenage years or adulthood.

Psychosis is a mental health problem that causes people to perceive or interpret things differently from those around them. The symptoms of psychosis usually begin abruptly and will cause the person affected to suddenly become very upset and agitated, and act in ways that are uncharacteristic.

Contact your child's care team if you notice a sudden and unusual change in their behaviour.

Psychosis can be treated with CBT or medication such as antipsychotics.

Read more about treating psychosis.

Children and young people with Prader-Willi syndrome are vulnerable to a range of related conditions as they grow up. You can read more about treating these conditions at the links below. 

A typical treatment plan for Prader-Willi syndrome

  • 0-2 years – compensate for the child's poor ability to feed, and consider surgery to correct undescended testicles in boys
  • 3-5 years – encourage a healthy diet, and usually begin a course of treatment with human growth hormone (HGH) to help growth
  • 6-12 years – behavioural problems usually become more of an issue at these ages, so encourage learning and development as you would with any other child
  • 12-18 years – prepare your child for the transition to adulthood, and manage any obesity-related conditions

Page last reviewed: 28/11/2014
Next review due: 28/11/2017