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What is Prader-Willi syndrome?

Prader-Willi syndrome is a complex genetic condition that affects different parts of the body. It is characterized by delayed development, weak muscle tone, feeding difficulties, poor growth, mild to moderate intellectual impairment, and behavioral problems.

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What causes
Prader-Willi syndrome?

In most cases, the cause of Prader-Willi syndrome is a segment that is missing from a patient’s genes.

Prader-Willi syndrome is not usually inherited, and there is often no family history of Prader-Willi syndrome before it is diagnosed.

Signs and symptoms

Prader-Willi syndrome causes a range of symptoms that may vary based on age group, and from person to person.

In infancy, common symptoms include:

Poor muscle

with feeding



In childhood, common symptoms include:

Excessive hunger

Short stature

Small hands and/or feet

Distinctive facial features


A young doctor in the office calms a worried blond teenage boy during an examination.
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Testing and Diagnosis

Prader-Willi syndrome is diagnosed with a blood test for genetic abnormalities. Testing and diagnosis may be carried out on an unborn child during pregnancy through non-invasive DNA testing, anytime after 9 weeks.

An early diagnosis allows for the affected child to have programs and treatment specifically tailored to their needs.

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There is no cure for Prader-Willi syndrome. Treatment focuses on managing symptoms and may include:


Devices that can help infants feed properly


Management of your child’s diet—keeping an eye on calories


Physical therapy, speech-language therapy, and special education to improve physical and
cognitive function


Therapy with growth hormone, testosterone, or estrogen

In the photo, two foams for injection of the drug Omnitrope.

Growth Hormone Treatment

Omnitrope® is a human growth hormone (HGH) treatment for growth hormone-related disorders, including Prader-Willi syndrome.

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In the foreground, smiling at the lens, a girl with a pink scarf around her neck, crouching next to her boxer dog. Behind her in the background embraced parents.


With early and ongoing treatment and proper support, infants and children diagnosed with Prader-Willi syndrome may be expected to have a normal lifespan.


Health and support

Advocacy groups can provide information, valuable guidance, and emotional support for you and your loved one who has been diagnosed with Prader-Willi syndrome.


Questions about Omnitrope?


To learn more about Omnitrope and our comprehensive patient support services, see our FAQ page for frequently asked questions about Omnitrope.


Contact Us

You can also call our OmniSource team at the number below. We can walk you through the process of getting started with Omnitrope.

Available: Monday – Friday, 8AM – 8PM ET

Phone: 877-456-6794