Beckwith-Wiedemann syndrome is a growth disorder that affects children. It may also increase a child’s risk of developing certain cancers. There’s no cure for BWS, but symptoms can be managed.

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Beckwith-Wiedemann syndrome (BWS) is a rare disorder present at birth that causes overgrowth in children. Signs and symptoms of BWS can range from mild to severe. Some children only have one or two symptoms, while others may have many symptoms.

Keep reading to learn more about BWS, what causes it, and what treatments may help improve a person’s quality of life.

BWS is a rare genetic disorder caused by abnormalities in a person’s chromosomes. This means that during conception — when the sperm meets the egg — and in early development, something changes in the chromosomes and causes excessive growth and other health issues down the line.

People with BWS have symptoms, like increased height and weight, starting before birth or at birth. They may also be more likely to develop tumors in certain parts of the body, like the liver or kidneys.

Genetic disorders can be passed down in families or happen by chance. Either scenario can be true for BWS, but it most often happens randomly.

Increased height and weight (above the 90th percentile) are among the most common symptoms of BWS. This overgrowth may start in utero. Half of babies with BWS are born at weights over the 97th percentile for their age. This excessive growth usually lasts until a child is around 8 years old.

Other symptoms include:

  • Hemihypertrophy: Hemihypertrophy, or asymmetrical growth, is when one half of the body grows faster than the other.
  • Macroglossia: Macroglossia is a large tongue.
  • Neonatal hypoglycemia: A baby with hypoglycemia has low blood sugar either at birth or very soon after birth.
  • Abdominal wall issues: Babies with BWS may have changes in the muscles of the abdomen. They may have conditions like an omphalocele or umbilical hernia.
  • Wilms’ tumor: A type of childhood tumor of the kidney, Wilms’ tumor is more common in children with BWS.
  • Hepatoblastoma: A type of liver tumor, hepatoblastoma is also more common in children with BWS.
  • Enlarged organs in the abdomen: Children with BWS may have an enlarged liver, kidneys, or pancreas.
  • Physical changes behind the ear: Children with BWS may have creases or pits behind the ears.
  • Cleft palate: Though rare, children with BWS may have a cleft palate.
  • Congenital heart disease: Children with BWS may have congenital heart disease, but this is also rare.

For most children with BWS, a genetic change on chromosome 11p15 causes the condition.

Chromosome 11 has some genes involved in growth and development. However, it’s not the only chromosome that regulates growth, and that isn’t its only function. A doctor can perform genetic testing that may determine the exact genetic cause of BWS in your child.

For example:

  • KvDMR hypomethylation is responsible for 50% of cases
  • UPD 11p15 is responsible for 20% of cases
  • H19 hypermethylation is responsible for 5% of cases

Around 80% of cases happen by chance during conception when the sperm meets the egg. Another 5% and 10% of people with BWS have a family history of the syndrome.

For the remaining people with BWS, doctors don’t know what caused it.

People born with BWS have a 50% chance of passing along the genetic change to their children through what is called autosomal dominant inheritance.

Otherwise, there are no known risk factors. The genetic mutation happens randomly.

There is no cure for BWS, but symptoms can be managed.

Treatment is individualized to the person to address their specific signs and symptoms. Your child may see a team of doctors to address issues in different parts of the body.

Treatments may include:

  • medication to address low blood sugars
  • surgery to correct abdominal issues, like omphalocele or an umbilical hernia
  • surgery to reduce the size of the tongue
  • orthotics (heel raise) to help with leg length difference and mobility
  • physical, occupational, and speech therapies to address individual needs
  • cancer treatments for Wilms’ tumor, hepatoblastoma, or other tumors

The outlook for people with BWS depends on its severity.

In general, excessive growth slows down by the time a child reaches age 8. Children with BWS are also more likely to develop tumors and certain cancers in this time frame and need to be regularly monitored and treated accordingly.

After childhood, people with BWS can grow into healthy adults who do not need any medical follow-up.

A doctor can make a diagnosis of BWS with a physical examination and observation of the different signs and symptoms. For example, a doctor may suspect BWS if they see asymmetrical overgrowth in the arms or legs along with an enlarged tongue.

A doctor may suggest genetic testing to get a better understanding of what changes are present on chromosome 11p15. This information can be used to help make an individualized treatment plan as well.

In some cases, a diagnosis may be made before birth through prenatal genetic testing.

Most cases of BWS happen at random, so there’s no way to prevent BWS from happening.

If you have BWS and are planning to have children, you can make an appointment with a genetic counselor to discuss your chances of passing along the syndrome.

How many people have BWS?

Experts estimate that around 1 in 10,000 to 15,000 children may be born with BWS. The true rate is difficult to tell because some people may have the condition with only mild symptoms, so they never get a diagnosis.

Do adults need follow-up care for BWS?

No. Most adults don’t need any medical care for BWS after childhood. Experts do recommend seeing a genetic counselor before having children to learn about the chances of passing along BWS.

Are there any clinical trials for people with BWS?

Yes. You can check out trials for BWS on It’s a database of clinical trials maintained by the U.S. National Library of Medicine.

If your child has received a BWS diagnosis, contact a doctor for more information. Your child’s pediatrician or another healthcare professional can help you understand how the syndrome will impact your child and what treatments may help.

You can find additional support at the Beckwith-Wiedemann Children’s Foundation International.