by EBSCO Medical Review Board
(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
Chromosome DNA
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.


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: 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.

Revision Information

  • Reviewer: EBSCO Medical Review Board Marcin Chwistek, MD
  • Review Date: 09/2020
  • Update Date: 04/23/2021