Prader-Willi syndrome (PWS) is a rare genetic condition that affects your child’s metabolism, growth, and development. One of the hallmark features of PWS is a constant feeling of hunger, which can lead to overeating and childhood obesity. While there is no cure, PWS is manageable with early diagnosis, diet and lifestyle changes, and ongoing support.

What Is Prader-Willi Syndrome?

Prader-Willi syndrome (PWS) is a genetic condition that affects metabolism and causes changes in both physical and behavioral development. In infancy, children with PWS often have very low muscle tone and difficulty feeding. Between ages 2 and 6, most children develop a chronic sense of hunger, known as hyperphagia, which can lead to obesity if not properly managed.

PWS occurs when specific genetic changes affect chromosome 15. In most cases, it happens randomly and is not inherited. In rare instances, it may be passed down in families. PWS can also cause developmental delays, behavioral challenges, and delayed puberty. If left untreated, it may lead to life-threatening complications, including respiratory illness, heart disease, diabetes, or sleep apnea. Treatment typically includes healthy eating habits, hormone therapy, and supportive therapies.

How Common Is Prader-Willi Syndrome?

PWS is considered a rare condition. It is estimated to affect 1 in every 10,000 to 30,000 children around the world. While rare, PWS is one of the most common known genetic causes of life-threatening obesity in children.

Types of Prader-Willi Syndrome

There are three genetic changes that can lead to Prader-Willi syndrome. These genetic types include:

• Chromosomal deletion – The most common cause of PWS is a missing segment of the paternal chromosome 15. This missing genetic material leads to the condition’s symptoms.
• Maternal uniparental disomy – In about 25% of cases, a child inherits both copies of chromosome 15 from their mother and none from their father. As a result, the necessary paternal genes are inactive.
• Translocation – In rare cases, a piece of chromosome 15 moves to another chromosome. This prevents the gene from functioning properly.

Prader-Willi Symptoms

Symptoms of PWS vary based on age and individual factors. Common symptoms in infancy include:

• Weak muscle tone (hypotonia)
• Poor feeding ability
• Weak cry
• Lethargy or tiredness

As children grow older, you may notice physical features such as:

• Almond-shaped eyes
• A triangular mouth
• A long, narrow head
• Short height
• Small hands and feet
• Underdeveloped genitals

Behavioral and developmental symptoms may include:

• Emotional outbursts (tantrums)
• Stubbornness
• Issues with cognitive development
• Obsessive-compulsive behaviors
• Sleep disturbances
• Eating large amounts of food
• Never feeling full (hyperphagia)

Hyperphagia is a key concern in PWS, as it can lead to childhood obesity and related health risks such as diabetes and heart disease.

Causes of Prader-Willi Syndrome

Prader-Willi syndrome is caused by changes in the genetic material on chromosome 15. Normally, you inherit one copy of each chromosome from each parent. In PWS, the paternal genes on chromosome 15 are either missing or not working correctly.

The genetic changes that lead to PWS include:

• Chromosomal deletion – The paternal copy of chromosome 15 is partially missing or nonfunctional. The maternal copy is present but turned off, leading to a lack of essential gene expression.
• Maternal uniparental disomy – The child receives two maternal copies of chromosome 15 and no paternal copy, which results in inactive genes.
• Translocation – A structural rearrangement places chromosome 15 material in the wrong location, preventing normal gene function.

These genetic errors are usually random and not inherited, although rare inherited cases can occur.

How Is Prader-Willi Syndrome Diagnosed?

Diagnosis of PWS usually begins with a physical exam, evaluation of your child’s symptoms, and a detailed medical history. If your child shows signs such as poor muscle tone, feeding issues, or excessive hunger, your provider may suspect PWS.

A genetic test is needed to confirm the diagnosis. This test can detect missing or altered genes on chromosome 15 and determine the specific genetic type of PWS.

Management of Prader-Willi Syndrome

There is no cure for PWS, but early treatment can significantly improve quality of life and prevent complications. Management focuses on controlling symptoms and supporting healthy development.

Treatment options may include:

• Special bottle nipples or other devices to support feeding and nutrition in infancy.
• A balanced diet with portion control to manage hunger and prevent obesity.
• Consultations with a registered dietitian or nutritionist for meal planning.
• Hormone treatments to promote growth and development.
• Supportive therapies, such as:
  • Physical therapy
  • Speech-language therapy
  • Counseling
  • Special education services

Ongoing care from a multidisciplinary team is important for long-term management.

Complications with Prader-Willi Syndrome

If not managed properly, PWS can lead to complications, mostly related to obesity and hormone deficiencies. Complications may include:

• Heart problems or heart disease
• Type 2 diabetes
• Respiratory issues
• Hypertension (high blood pressure)
• Sleep apnea

Treating PWS early and managing weight can significantly reduce the risk of complications.

FAQs

What Is the Life Expectancy of Prader-Willi Syndrome?

With early diagnosis and proper management, people with PWS can live a normal lifespan. Ongoing support, healthy lifestyle habits, and medical monitoring are key to improving outcomes.

Is There a Cure for Prader-Willi Syndrome?

There is currently no cure for PWS. However, ongoing research continues to explore potential genetic therapies and medications to better manage the condition. While a cure may not yet exist, people with PWS can lead fulfilling lives with the right combination of medical, nutritional, and behavioral care. Support from a dedicated care team and family members plays a critical role in helping individuals thrive.

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