Medically reviewed by Daniel Combs, MD
:max_bytes(150000):strip_icc():format(jpeg)/Health-pw-2000x420-eb48a8f86f3e454d8c60e5b56d09c257.png "Illustration of a young child in a high chair showing a displeased facial expression with a plate and cup in front of them")
- Prader-Willi Syndrome (PWS) is a rare genetic disorder that causes a variety of symptoms, including constant feelings of hunger that can lead to overeating and obesity.
- Other possible symptoms include poor motor skills, short height, underdeveloped sex organs, and mild cognitive disabilities.
- Treatment options may include growth hormone injections, regular exercise, and a plan to monitor eating. Behavioral therapy may also be helpful.
Prader-Willi Syndrome (PWS) is a rare genetic disorder that causes constant feelings of hunger, as well as poor muscle tone and low levels of sex hormones. People with PWS are at risk of overeating and developing obesity because their brains never tell them that they are full. While there is no cure for PWS, there are ways to manage it.
Prader-Willi Syndrome Symptoms
Prader-Willi Syndrome is a genetic disorder that affects several aspects of mental and physical health. The symptoms and their severity can vary from person to person. The symptoms can also be different as the person ages.
Infants with PWS may have the following symptoms:
- Poor muscle tone (the baby appears “floppy”)
- Lethargy
- A weak cry
- Trouble sucking
- Long, narrow head
- Narrow forehead
- Almond-shaped eyes
- A narrow bridge of the nose
- A thin upper lip and downturned mouth
- Undescended testes in babies assigned male at birth
As a child with PWS gets older, they may experience the following symptoms:
- Poor motor skills
- Delayed milestones
- Short height
- Small hands and feet
- Curved spine (scoliosis)
- Weight gain
- Underdeveloped sex organs
- Some learning disabilities
- Behavioral issues
- Sleep problems
Children, adolescents, and adults with PWS feel very hungry and do not feel satisfied after eating, known as hyperphagia. They typically eat a large amount of food. It is common for people with PWS to overeat and quickly gain weight.
What Causes Prader-Willi Syndrome?
Prader-Willi Syndrome occurs when certain genes in chromosome 15 don't function properly. Most people inherit one copy of chromosome 15 from each parent. The copy from the father (paternal copy) usually has some genes that are active and some that are inactive.
About 70% of PWS cases happen when a specific section of the paternal copy of chromosome 15 is deleted. When genes on chromosome 15 can't function normally, they lead to DNA changes that cause PWS symptoms.
The genetic mutation that causes PWS is believed to be random in most cases. Most people with PWS did not inherit the disorder from their parents, and it does not usually run in families. PWS is rare, affecting about 1 in 10,000-30,000 people worldwide.
Diagnosis
In most cases, healthcare providers diagnose Prader-Willi Syndrome after noticing physical signs in a newborn. Newborns who have poor muscle tone, feel floppy in your arms, and have trouble eating may require PWS testing.
Early diagnosis is critical to starting early treatment and special needs programs. To diagnose PWS, healthcare providers perform genetic testing to look for abnormalities in chromosome 15. Genetic testing can also help parents understand if future children could be at risk.
Treatments for Prader-Willi Syndrome
There is no cure for Prader-Willi Syndrome. People with PWS require lifelong care and support.
PWS treatment options for newborns and infants usually focus on addressing their feeding difficulties. An infant with PWS will likely need a special bottle nipple or tube feedings to receive enough nutrition.
As a child gets older and their appetite increases dramatically, they require help managing their food. Children with PWS need strict supervision when it comes to eating. Many parents need to put locks on their pantries and refrigerators to prevent their children from constantly eating. A dietitian or nutritionist can help develop a healthy eating plan for the child.
Most children with PWS benefit from participating in an early intervention special needs program. This may include speech therapy, occupational therapy, and special education.
Other treatment options for PWS include:
- Growth hormone (GH) therapy: People with PWS have low GH levels. GH therapy can help increase their height and muscle mass. It can also improve motor skills and flexibility.
- Medications: Some people with PWS benefit from taking a serotonin reuptake inhibitor to address behavioral challenges.
- Sex hormone therapy: Because people with PWS have low levels of sex hormones, they may require hormonal therapy or corrective surgery to treat small genitals.
- Ophthalmology care: People with PWS often have trouble focusing their eyes and may need to see an ophthalmologist regularly.
- Orthopedic care: Because PWS causes the spine to curve to the side, most people need to see an orthopedist regularly.
- Physical therapy: Working with a physical therapist can help with muscle weakness and developmental milestones.
- Behavioral therapy: Children with PWS often have behavioral problems, including angry outbursts and obsessive-compulsive behavior. Working with a therapist to implement boundaries can be helpful.
Related Conditions
Prader-Willi Syndrome causes a person to feel incredibly hungry even after eating. This significantly raises the risk of overeating, weight gain, and obesity. Obesity raises the risk of several chronic health conditions, including type 2 diabetes, heart disease, and obstructive sleep apnea.
People with PWS have such a strong urge to eat that they may consume spoiled food or even garbage. This puts them at risk for foodborne illness and other infections. If left unattended, their binge eating could cause gastrointestinal complications, such as a tear in the intestinal wall.
To avoid these complications, people with PWS need constant supervision around food.
Living With Prader-Willi Syndrome
Prader-Willi Syndrome is a lifelong disorder. People with PWS need supervision and specialized care through adulthood. Adults with PWS often live in a group home with supervision and structure. This can help them avoid issues like overeating.
