Prader-Willi syndrome

Prader-Willi syndrome is a rare genetic condition that affects growth and development. About 1 in 15,000 children are born with the condition and it affects both boys and girls. 

Children with Prader-Willi syndrome often have feeding problems as babies, but within a few years they develop an excessive appetite. This can lead to obesity and diabetes if it’s not properly managed. 

Other symptoms include having cognitive (thinking) and learning difficulties, and behavioural challenges. 

There are ways to support people with Prader-Willi syndrome to help them lead healthy, fulfilling lives.  

Video: What is Prader-Willi syndrome?

Prader-Willi syndrome occurs due to gene abnormalities associated with chromosome 15. This happens by chance and is not passed down in families. Why it happens is unknown. This genetic change affects the part of your brain (the hypothalamus) that regulates hormones and appetite, as well as the development of muscle tone and expression of emotions. 

The symptoms of Prader-Willi syndrome can range from mild to severe in individuals. There are key symptoms that appear during 2 different stages of childhood. 

Babies

Babies tend to be floppy as they have weak muscle tone. This also affects their ability to breastfeed as they have trouble sucking – they often need feeding support such as a feeding tube. As a baby grows, there are noticeable delays in their physical and mental development. They don’t reach their milestones at the same times as other babies and may take longer in learning to walk and talk. These babies and infants can commonly stop breathing when asleep and this needs assessing early in case it needs closer management. Infants usually fail to thrive and need nutritional/dietitian support including, at times, feeding tubes. 

Children

The early difficulties with food intake change by 3 to 4 years of age and then the children with Prader-Willi syndrome start wanting to eat all the time as they’re no longer satisfied with a normal amount of food. They also have a lower metabolism which means they don’t need as much food as other children their age. Because they can’t control their appetite, their eating needs to be monitored so they don’t gain too much weight.

Children with Prader-Willi also remain quite weak and floppy, partly because they don’t have as much muscle as other children. Growth hormone therapy has dramatically changed these children’s body composition, increasing their muscle mass, making them stronger and more able to do physical activities.

Children with Prader-Willi syndrome tend to have small hands and feet, and often develop curvature of the spine (scoliosis). Learning difficulties and behavioural challenges, such as temper tantrums and emotional outbursts, are a key feature of Prader-Willi syndrome. Some children may also develop obsessive compulsive behaviours such as skin picking. 

Teenagers and adults

Other problems that commonly develop later include an insatiable appetite (can't get enough food) which often worsens during childhood. This results in overeating and obesity. If obesity develops, type 2 diabetes can occur along with sleep and breathing issues. Most of these children won't enter puberty and can develop osteoporosis if they're not given replacement sex hormones. 

Talk to your healthcare provider if you’re concerned your child has Prader-Willi syndrome. A genetic test is needed to diagnose the condition.

Treatment aims to manage the symptoms associated with this condition. 

This includes:

• early assessment for sleep apnoea as an infant – if it's not diagnosed it can be life threatening
• dietitian input and sometimes feeding tubes over the first 2 years to help with nutrition and growth
• after 3 to 4 years of age, a healthy, balanced diet avoiding sweet and high calorie foods is required
• encouraging exercise to build muscle mass
• specific behaviour management targeting the issues these children commonly have – there are 2 videos linked in the section for healthcare providers below, where a US doctor talks to parents about managing behaviour.

Growth hormone treatment should be started early (within the first 6 months of life ideally) as it helps with muscle mass and strength, reduces fat mass, possibly helps with cognition and improves growth. 

Most people with Prader-Willi syndrome need specialised care and support from their whānau and healthcare providers throughout their lives.

Following the advice of healthcare providers in caring for your family member with Prader-Willi syndrome makes it easier for you and for them. This includes keeping food out of sight, sticking to a routine and being clear and firm in your instructions.

In the following video parents and people with Prader-Willi syndrome talk about the condition and how it affects them.

Video: Prader-Willi syndrome – the children who are always hungry

Remember to take care of your own needs for sleep, exercise, healthy eating and time for yourself. Counselling can help. Talk to your healthcare provider for a recommendation or find a counsellor(external link). 

It’s important that you get support for yourself (see the support options below).

Prader-Willi Syndrome Association NZ(external link) Freephone 0800 4 PWS HELP
Disability services funded by Health New Zealand | Te Whatu Ora