A genetic disorder that causes obesity, intellectual disability and shortness in height. Prader-Willi syndrome is a genetic disorder usually caused by deletion of a part of chromosome 15 passed down by the father. The most common symptoms of Prader-Willi syndrome are behavioural problems, intellectual disability and short stature.
Prader-Willi syndrome is a rare genetic disorder that affects development and growth. It is thought that around one in 10,000 to 20,000 children are born with the syndrome, with females slightly more likely to have the condition than males. There is no cure for Prader-Willi syndrome, but professional health care from a range of specialists can improve the child’s quality of life. Prader Willi Syndrome affects many parts of the body. People with this condition feel hungry all the time and become obese. They also have poor muscle tone, reduced mental ability, and underdeveloped sex organs. In order to improve the outlook for each child with PWS, it is important that experienced doctors work with families to determine an individualized diagnosis and treatment plan as early as possible.
Symptoms of Prader-Willi syndrome
Typically, a child with Prader-Willi syndrome is unusually floppy at birth and has feeding difficulties and a weak cry. Males often have testes that haven’t moved to the scrotum (undescended testes) and may have underdeveloped genitalia.
Children with Prader-Willi syndrome are delayed in all aspects of development, reaching developmental milestones – such as sitting, crawling and walking – later than other children. The average IQ of a child with Prader-Willi syndrome is around 70, but the degree of intellectual disability will differ for each child. By five years of age, a feature of Prader-Willi syndrome is excessive appetite, which can lead to obesity if not carefully managed.
- Newborns are often small and floppy with reduced muscle tone
- Male infants may have undescended testicles
- Trouble feeding as an infant, with poor weight gain
- Almond-shaped eyes
- Delayed muscle and motor function development
- Narrowed head at the temples
- Rapid weight gain
- Short stature
- Slow mental development
- Very small hands and feet in comparison to the child's body
Causes of Prader-Willi syndrome
Humans have 23 pairs of chromosomes, with one set inherited from each parent. Research indicates that missing genes on the copy of chromosome 15 contributed by the father cause Prader-Willi syndrome. This can happen in four ways:
- The copy of chromosome 15 contributed by the father is altered – usually, genes are deleted. This is the most common cause, accounting for between 60 and 70 per cent of cases.
- The baby inherits two copies of chromosome 15 from the mother, and none from the father. This happens in about 25 to 30 per cent of cases.
- A translocation occurs, which means some of the genes on the copy of chromosome 15 contributed by the father get shuffled around or swapped with genes from other chromosomes.
- The copy of chromosome 15 contributed by the father is intact, but the genes in the Prader-Willi region do not work properly.
Treatment
There is no cure for Prader-Willi syndrome and it cannot be prevented. Treatment aims to ease some of the associated problems. Depending on the needs of the person, some of the treatment options may include:
- Strict supervision of diet (there are no medical means of curbing appetite)
- Plenty of physical activity to help maintain the child’s body weight within the normal range
- Growth hormone treatment to overcome the hormone deficiency that contributes to the child’s short stature
- Hormone therapy to increase muscle mass
- Hormone therapy to boost inadequate sex hormone levels
- Medication to help control any obsessive and compulsive behaviours
- Orthopaedic treatment for scoliosis or kyphosis
- Appropriate prescription eye glasses
- Specialist care from a range of healthcare professionals.
