Prader-Willi Syndrome

What is Prader-Willi Syndrome?

Prader-Willi syndrome is a rare genetic disorder characterized by physical, mental, and behavioral differences. Children who have Prader-Willi syndrome often have an extremely high appetite that often leads to obesity unless a strict diet is upheld. 

What are the Signs and Symptoms of Prader-Willi Syndrome?

The signs and symptoms of Prader-Willi Syndrome can vary. The following characteristic symptoms are usually seen first in early infancy: 

  • Low muscle tone and weakness
  • Feeding difficulties leading to slow growth
  • Delayed developmental milestones

Beginning in early childhood through adulthood, the following features are common:

  • Excessive appetite, eating, and weight gain
  • Intellectual disability and learning difficulties
  • Differences in puberty and reproductive organs
  • Behavioral outbursts and psychiatric concerns
  • Characteristic facial features
  • Difficulty sleeping
  • Short stature

Many infants with Prader-Willi also have a characteristic facial appearance which is usually characterized by:

  • Almond shaped eyes
  • A narrow forehead
  • A turned-up nose

Find a Pediatric Geneticist

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What Causes Prader-Willi Syndrome?

Prader-Willi syndrome happens when there is a change to a specific part of chromosome 15 contributed by the child’s father. Usually, it is the result of a deletion where a small part of chromosome 15 is missing, which leaves the body without a portion of the instruction manual. Some individuals with Prader-Willi syndrome have a different type of change called uniparental disomy or an imprinting center defect, which prevents the genes in this area from working normally.

Prader-Willi syndrome happens as a sporadic event in most cases. Unlike genetic conditions that are inherited from a parent, it is usually a brand-new genetic change in a child with no other affected family members. In these new cases, the condition occurs randomly and is not caused by any specific action or exposure.

Unfortunately, there is no known way to prevent Prader-Willi syndrome. However, early diagnosis and treatment can help manage the symptoms. It can also reduce complications, and improve the quality of life for individuals with the condition.

How is Prader-Willi Syndrome Diagnosed?

Prader-Willi syndrome is usually diagnosed with a physical examination, chromosome testing, and genetic testing.

Early diagnosis allows people with Prader-Willi syndrome to receive recommended medical management. Since there are other conditions with overlapping health problems, it is important to see a health care provider familiar with Prader-Willi syndrome for a thorough physical exam. 

The diagnosis should be confirmed with a genetic test that looks closely at the chromosomes and gene expression in the Prader-Willi region of chromosome 15, called a methylation analysis. This and other confirmatory tests can determine the chance of having another child with Prader-Willi syndrome since certain rare forms have a higher chance of occurring again in a family. 

How is Prader-Willi Syndrome Treated?

After diagnosis, a personalized treatment plan is made to manage symptoms, reduce complications, and improve the quality of life for people with Prader-Willi syndrome and their families.

Treatment for this genetic condition typically involves a combination of medical, educational, nutritional, and behavioral health management guidelines such as:

  1. Medical management by the primary care physician along with a team of specialists to treat the various symptoms.
  2. A strict diet to control food intake. This should include portion control, regular meals, and watching for food seeking behaviors.
  3. Growth hormone therapy to help with growth issues and improve muscle tone.
  4. Exercise to reduce excessive weight and improve overall health.
  5. Behavioral therapies to address concerns such as impulsivity, aggression, and difficulty with social interactions. This may include use of psychiatric medication.
  6. Regular monitoring for complications such as diabetes and sleep apnea.
  7. Home and school-based interventions as needed, such as speech therapy, occupational therapy, and individualized education plans.
  8. Genetic counseling and support for the family, as well as connection to resources and social services.

CHRISTUS Genetics Clinic

CHRISTUS Children's has a monthly Prader-Willi syndrome multidisciplinary clinic based in San Antonio, Texas. If you or your child has a confirmed diagnosis of Prader-Willi, you can be referred to the clinic to receive coordinated care from our experienced specialists, including geneticists, ENT doctors, endocrinologists, pulmonologists, sleep medicine specialists, psychologists, dietitians, social workers, and speech pathologists.


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