Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a genetic condition. It can affect both boys and girls and at equal rates. It is hard to say exactly how many children are born with PWS, but the low range estimate is around 1 in 30,000. It is usually described as having two phases. Phase 1 is from birth until they are about 2 years old. Phase 2 can happen anytime between 1 to 6 years old, usually between 2 and 4 years old.

During Phase 1, a child with PWS is very weak and has very low muscle tone. Most can not suckle well and often will require tube feeding, with many experiencing Failure To Thrive. The second phase starts when the child begins developing an abnormal interest in food and eating. This does not happen over night but over a period of time. These changes leads to obesity from an early age.

How will PWS affect my child?

Short stature is almost always present, especially during the second year, because of low levels of  growth hormone in the body. Children with PWS do not experience the normal growth spurt when they reach puberty. If they do not receive treatment, they will become adults who are shorter than the average population  Men with PWS are on average 22-24 cm shorter than men without PWS. Women with PWS are on average 15-18 cm shorter than women without PWS.

In addition, most persons with PWS have learning disabilities and a few may develop behavioural problems which could require additional care and management. Delays in motor development and puberty/sexual functions (hypogondism) are also common in children with PWS.

How is PWS diagnosed?

Although PWS can easily be identified from well-defined physical criteria, to confirm a diagnosis a genetic test is needed (conducted by a licensed laboratory). Over the last 10 years, the age of when a child is diagnosed has gotten much younger. Now, the majority of cases are diagnosed during the first months of life. This earlier diagnosis may allow for an earlier start of therapies to reduce the problems associated with PWS, in particular by preventing obesity. This will not only increase the quality of life for patients but also reduce the burden on the family and care.

Treatment with Growth Hormone

Growth hormone treatment is used in children with PWS for several reasons: to improve growth during childhood, to improve adult height, and to improve body composition (fat to muscle). Growth hormone injections are normally given once-daily in the evening. At the beginning, parents are trained to give these injections when the child is very young. As children become more comfortable, they may choose to inject themselves. Devices are now available that make injecting growth hormone easier, more comfortable and less painful. This has been achieved through advances in design and the use of very fine needles. There is a wide range of devices to choose from with different features that may fit better with different lifestyles. It is a good idea to ask a doctor or nurse about these different attributes when choosing a device.

To help the doctor select an injection device that matches your requirements, it may help to read the page discussing the features of the various devices.

APROM ID# 4423. December 2012.