Prader-Willi syndrome Dr Trisha Macnair Behavioural problems are common symptoms.

In this article

What is Prader-Willi syndrome? Symptoms

Causes and risk factors Treatment and recovery

Advice and support

Prader-Willi syndrome (PWS) is a chromosomal disorder with symptoms that include learning difficulties, obesity and behavioural problems.

At birth, babies are usually small and floppy, with low muscle tone, and have problems feeding. They may have small hands and feet, and boys may have undescended testicles. The babies are slow to get walking and these poor motor skills may persist into adult life.

After about six months to a year, especially as the child becomes mobile, they develop an interest in food that may become an insatiable obsession. Weight gain can be rapid, leading to severe obesity that results in diabetes, strain on the heart, lungs and skeleton, and even early death.

Other symptoms can include:

• Learning difficulties
• Short stature
• Underdeveloped genital organs
• Behavioural problems

People with PWS often have obsessive/compulsive behaviour and may hoard possessions and show repetitive habits such as picking at skin or hair. They are unsettled by changes in routine and can show unpredictable rages and aggression. Some individuals are more severely affected than others.

Some people have also noticed that children with PWS may be unusually blonde and blue-eyed.

PWS is a genetic condition that occurs in one in 15,000 to 20,000 live births. Prader-Willi syndrome (PWS) results from disruption of chromosome 15. This leads to a disruption of a part of the brain called the hypothalamus, which controls appetite.

Genetic tests on blood can confirm the diagnosis, and may be done antenatally using CVS or amniocentesis if there's known to be a risk. However, in most cases the condition doesn't recur within one family.

As PWS is a genetic condition, it can't be cured. Support for specific problems such as learning difficulties and, most importantly, managing appetite and diet is essential.

Although children with PWS are always voraciously hungry, they actually require slightly fewer calories than a normal child, so it can be particularly difficult to control weight. In addition the child may go to great lengths to get food. Parents and carers may have to take strict measures to control food intake.

Recent research has suggested treatment with growth hormone can help to improve growth and reduce the proportion of body fat, as well as improving physical strength and agility. Hormonal treatments may also be useful to develop the genital organs.

Prader-Willi Syndrome Association (UK)

Tel: 01332 365676
Email: admin@pwsa.co.uk
Website: pwsa.co.uk

This article was last medically reviewed by Dr Orlena Kerek in March 2009