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 random genetic defect. The defect is most often caused by a gene from the father.

Genetic Material

Copyright © Nucleus Medical Media, Inc.

Risk Factors

There are no known risk factors. About 1% may have a family history.


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 normal development, such as language skills and walking
  • Behavior problems, such as temper tantrums and stubbornness
  • Short stature compared to peers in the family
  • Increased hunger

Older children may have:

  • Insatiable hunger
  • Increased behavior problems, such as:
    • Anger and inflexibility
    • Problems with transitions
    • Mood swings
    • Obsessive habits
  • Learning problems
  • Fatigue
  • Sleep problems
  • High threshold for pain
  • Problems sensing temperature extremes


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:

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


There are no known guidelines to prevent PWS.


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:
...(Click grey area to select URL)
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: Accessed November 25, 2020.
Last reviewed September 2020 by EBSCO Medical Review Board Marcin Chwistek, MD
Last Updated: 4/23/2021

EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.

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.

To send comments or feedback to our Editorial Team regarding the content please email us at Our Health Library Support team will respond to your email request within 2 business days.