Prader-Willi syndrome (PWS) is group of symptoms caused by a rare genetic problem. It can cause a variety of problems with growth and development.
PWS is caused by a random genetic defect. The defect is most often caused by a gene from the father.
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There are no known risk factors. About 1% may have a family history.
Some physical features in people with PWS are:
Other symptoms of PWS can change as the child ages.
Infants may have:
Toddlers may have:
Older children may have:
The doctor will ask about your child's symptoms and health history. This may be enough to suspect PWS.
A genetic test can help to confirm the diagnosis. This test is done with a sample of blood.
There is no cure. Lifetime treatment will be needed to manage symptoms. Some methods are:
There are no known guidelines to prevent PWS.
March of Dimes
Prader-Willi Syndrome Association
About Kids Health—The Hospital for Sick Children
Foundation for Prader-Willi Research
About Prader-Willi syndrome. Foundation for Prader-Willi Research website. Available at:
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Accessed November 25, 2020.
Driscoll DJ, Miller JL, et al. Prader-Willi Syndrome. GeneReviews 2016 Feb 4.
Prader-Willi syndrome. EBSCO DynaMed Plus website. Available at: https://www.dynamed.com/condition/prader-willi-syndrome-27. Accessed November 25, 2020.
Last reviewed September 2020 by
EBSCO Medical Review Board
Marcin Chwistek, MD
Last Updated: 4/23/2021