Prader-Willi Syndrome Diagnosis & Treatments

A suspected diagnosis of Prader-Willi syndrome (PWS) is usually made by a physician based on clinical symptoms. PWS should be suspected in any infant born with significant hypotonia (muscle weakness or "floppiness").  The diagnosis is confirmed by a blood test. The preferred method of testing is a "methylation analysis," which detects >99% of cases, including all of the major genetic subtypes of PWS (deletion, uniparental disomy, or imprinting mutation).  A "FISH" (fluorescent in-situ hybridization) test will identify those patients with PWS due to a deletion, but it will not identify those who have Prader-Willi syndrome by "UPD" (uniparental disomy) or an imprinting error.

Almost all cases of PWS can be confirmed by one of the above tests. However, in the rare event that laboratory tests do not confirm PWS, a clinical diagnosis can be helpful for the development of a management plan.

Is Prader-Willi syndrome curable?
Currently, there is no cure for PWS. Our work to accelerate PWS research offers hope for the development of more effective treatments and an eventual cure.

Are any treatments available for Prader-Willi syndrome ?

The treatment of PWS is currently based on treating the symptoms of the disorder as they arise. Growth hormone deficiency is present in almost all children, and many adults, with PWS.  In multiple studies, human growth hormone (HGH) has been found to be beneficial for those with Prader-Willi syndrome. In June of 2000, HGH was officially approved by the Federal Drug Administration (FDA) in the United States for use in patients with Prader-Willi syndrome.  HGH is effective not only in increasing height, but also in decreasing body fat, increasing muscle mass, improving weight distribution, increasing stamina, and increasing bone mineral density.  In addition, studies suggest its positive effects on development and behavior.

Despite HGH treatment, many challenging symptoms associated with PWS remain difficult to treat.  The inability to control food intake is often the biggest obstacle keeping those with PWS from living independently.  To date, no medications have proven effective in regulating appetite in PWS, and therefore, strict environmental control and constant supervision are the only ways to prevent life-threatening overeating and extreme obesity at present.  However, there are a number of novel anti-obesity drugs in clinical development, some of which might benefit the PWS population, and evaluation of these drugs in clinical trials is an important priority for FPWR.  

Additional challenges in PWS include excessive daytime sleepiness, which may be improved by the wake-promoting drug, modafinil.  Hormone abnormalities common in PWS (low thyroid hormones, testosterone, estrogen) may be treated by an endocrinologist with standard medications.  Scoliosis is also very common in PWS and should be treated by an orthopedic physician familiar with PWS.  Finally, management and treatment of the psychiatric and behavioral issues associated with PWS also remain very challenging.  A combination of behavioral therapy, environmental control, and medication may be needed.  Consultation with mental health professionals familiar with PWS is recommended.

For more information about PWS and available educational and support services, please visit the Genetic Alliance Disease InfoSearch for PWS, National PWSA-USA website, the PWS Medical Home Portal, or PWS Notes (a site run by parents).  Another excellent resource, especially for those living in the UK or Europe, is the PWSA (UK) website. The site has information for parents, caregivers, and others interested in learning more about PWS. A number of forums are available on the site for discussing PWS-related topics.