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Prader-Willi Syndrome

  • Cynthia M. Johnson, MA
Publication Type:


Prader-Willi Syndrome

(Prader-Labhart-Willi Syndrome)


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 genetic problem that is most often passed from the father to the child.

Genetic Material.

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Risk Factors

There are no known risk factors for PWS. A few people with it may have a family history of it.


Some physical features in people with PWS are:

  • Almond-shaped eyelid openings
  • Poor eye alignment
  • A thin upper lip
  • A downturned mouth
  • A narrow forehead
  • Small hands and feet

Other symptoms of PWS can change as the child ages.

Infants may have:

  • Problems feeding
  • Slow growth
  • A weak, squeaky cry
  • Sleepiness

Toddlers may have:

  • A delay in developing language, walking, and other skills
  • Behavior problems, such as temper tantrums
  • Shorter stature compared to peers
  • Increased hunger

Older children may have:

  • Hunger that does not go away, even when they have eaten
  • More behavior problems, such as:
    • Anger and inflexibility
    • Problems moving from one activity or place to another (such as stopping playing to go to school)
    • Mood swings
    • Obsessive habits
  • Learning problems
  • Fatigue
  • Sleep problems
  • High threshold for pain
  • Problems sensing temperature extremes


The doctor will ask about symptoms and health history. This may be enough to suspect PWS.

A genetic test can help confirm the diagnosis. This test is done with a blood test. Other hormone tests may be done to see if there is a higher risk for other problems.


The goal of treatment is to manage symptoms. There is no cure for PWS. Lifetime treatment will be needed. Some ways to do this are:

  • Nutrition support to make sure the child gets the right amount of calories and stays at a healthy weight
  • Lifestyle changes, such as working out
  • Physical, speech, and occupational therapy to help with developmental delays
  • Special education services
  • Medicines to help with feeding and behavior issues, as well as:
    • Growth hormones to help with height
    • Hormone replacement therapy to help with development


There are no known guidelines to prevent PWS.





  • Driscoll, D.J., Miller, J.L., et al. Prader-Willi Syndrome. GeneReviews, 2017. Available at: https://www.ncbi.nlm.nih.gov/sites/books/NBK1330.
  • Prader-Willi syndrome. EBSCO DynaMed Plus website. Available at: https://www.dynamed.com/condition/prader-willi-syndrome-27.
  • What is Prader-Willi syndrome? Foundation for Prader-Willi Research website. Available at: https://www.fpwr.org/what-is-prader-willi-syndrome.


  • Marcin Chwistek, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.