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Prader-Willi Syndrome (PWS): Condition Information

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What is PWS?

The term PWS refers to a genetic disorder that affects many parts of the body. Genetic testing can successfully diagnose 99% of infants with PWS.1

The syndrome usually results from deletions or partial deletions on chromosome 15 that affect the regulation of gene expression, or how genes turn on and off. Andrea Prader and Heinrich Willi first described the syndrome in the 1950s.2

One of the main symptoms of PWS is the inability to control eating. In fact, PWS is the leading genetic cause of life-threatening obesity. Other symptoms include low muscle tone and poor feeding as an infant, delays in intellectual development, and difficulty controlling emotions.

There is no cure for PWS, but people with the disorder can benefit from a variety of treatments to improve their symptoms. These treatments depend on the individual's needs, but they often include strict dietary supervision, physical therapy, behavioral therapy, and treatment with growth hormone, among others. As adults, people with PWS usually do best in special group homes for people with this disorder. Some can work in sheltered environments.


  1. Cassidy, S. B., Schwartz, S., Miller, J. L., & Driscoll, D. J. (2011). Prader-Willi syndrome. Genetics in Medicine, 14, 10-26. [top]
  2. Prader, A., Labhart, A., & Willi, H. (1956). [A syndrome characterized by obesity, short stature, cryptorchidism, and oligophrenia following a myotonia-like condition in infancy]. Schweizerische Medizinische Wochenschrift, 86, 1260. [top]

Last Updated Date: 01/30/2014
Last Reviewed Date: 01/14/2014
Vision National Institutes of Health Home BOND National Institues of Health Home Home Storz Lab: Section on Environmental Gene Regulation Home Machner Lab: Unit on Microbial Pathogenesis Home Division of Intramural Population Health Research Home Bonifacino Lab: Section on Intracellular Protein Trafficking Home Lilly Lab: Section on Gamete Development Home Lippincott-Schwartz Lab: Section on Organelle Biology