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Beckwith-Wiedemann Spectrum or Isolated Lateralized Overgrowth

Also called: Beckwith syndrome, macroglossia-omphalocele-visceromegaly syndrome, isolated hemihypertrophy

Beckwith-Wiedemann spectrum (BWS) is a genetic disorder that can cause overgrowth of body parts (hypertrophy) and other medical issues. Overgrowth may be limited to 1 body area, such as the legs, head, tongue, or other area. This is called lateralized overgrowth. Isolated lateralized overgrowth is lateralized overgrowth with no other signs of BWS. You may hear isolated lateralized overgrowth called isolated hemihypertrophy.

Most children with BWS or isolated lateralized overgrowth grow up to be healthy adults. By the time the children are teens, their growth tends to become more typical and their cancer risk reduces to that of the general population. Adults with these syndromes usually have normal abilities and lifespans.

Cancer risk with Beckwith-Wiedemann spectrum or isolated lateralized overgrowth 

Children with BWS or isolated lateralized overgrowth have a higher risk of developing a kidney tumor called Wilms tumor. Most Wilms tumors develop before age 5. But some children can develop Wilms tumor later. These children also have a higher risk of developing a liver cancer called hepatoblastoma. Most hepatoblastomas develop by age 2.

Children with this syndrome may develop other types of cancer, including:

The risk for all types of tumors in children with BWS is between 4% (about 1 in 20) and 21% (about 1 in 5). The risk for all types of tumors in children with isolated lateralized overgrowth is about 6% (1 in 17). The greatest time of risk is in the first 8 years of life.

Signs of Beckwith-Wiedemann spectrum

Children with BWS may have:

  • Neonatal hypoglycemia: Blood sugar levels that are very low as a newborn
  • Macroglossia: Enlarged tongue
  • Neonatal macrosomia: Birth weight greater than 90th percentile.
  • Postnatal overgrowth: Height and length greater than 90th percentile.
  • Creases or pits in or around the ear lobe
  • Hemihyperplasia: One side of the body grows larger than the other side.
    • Omphalocele: A birth defect in which organs in the belly poke out through the belly button. These organs are covered in a sac made of a thin layer of body tissue. The condition is treated with surgery when the child is an infant.
    • Umbilical hernia: A birth defect in which there is a bulge near and under the belly button. This may be treated with surgery, depending on the size of the hernia.
    • Larger than normal organs in the abdomen (belly)
    • Abnormal kidney(s)
    • Abnormal heart
    • Cleft palate: A gap in the roof of the mouth. This gap is treated with surgery.

Other physical issues may include:

  • Polyhydramnios: Too much amniotic fluid during pregnancy
  • Diastasis recti: Separation of the right and left sides of the main muscle in the abdomen
  • Hemangiomas: Noncancerous growths on blood vessels
  • Nevus flammeus: Port-wine stain birthmarks

Causes of Beckwith-Wiedemann spectrum or isolated lateralized overgrowth

Most cases of BWS and some cases of isolated lateralized overgrowth are caused by changes called “methylation defects.” Chromosomes carry genetic information that tells cells in the body how to function. The methylation defects affect a region of chromosome 11 called 11p15.

The genes located at 11p15 help control how and when cells grow, divide, and die. The methylation defects cause these genes to not work correctly in people with BWS or isolated lateralized overgrowth. Cells with changes in 11p15 can grow and divide in an abnormal way. Researchers believe this helps cause the enlarged body parts. It may also lead to tumor growth.

Pregnancies using in vitro fertilization (IVF) are at higher risk of having BWS caused by methylation defects. The risk of BWS in children conceived using IVF is between 1 in 4,000 and 1 in 1,000.

About 80–85% of children with BWS or isolated lateralized overgrowth do not inherit the condition from a parent. These children have no history of the condition in their family. In these cases, the methylation defects on chromosome 11p15 either happened in the egg or sperm cell that formed the child. Or the changes happened in one of the child’s cells during pregnancy. These children are the first in their families to have BWS or isolated lateralized overgrowth.

A small number of children with BWS have the condition because of changes in a gene called CDKN1C or because of an abnormality of chromosome 11p15.

The risk of passing the condition to future children depends on the type of change found on chromosome 11p15 after genetic testing. A genetic counselor can explain the risks.

Diagnosis of Beckwith-Wiedemann spectrum and isolated lateralized overgrowth

Health history

A health care provider may suspect that your child has BWS after studying their medical or family cancer history. This information helps the health care provider and the genetic counselor know if:

  • There are more cancers than normal in your family
  • These cancers happened at a younger age than expected
  • The cancers are those that are seen in BWS

Your provider or genetics counselor may recommend genetic testing if they suspect BWS.

Genetic testing for BWS

A blood sample is sent to a genetic testing lab. The lab runs genetic tests that looks for changes in certain areas on chromosome 11p15.

If genetic changes are found that diagnose BWS or isolated lateralized overgrowth, a genetic counselor will work with your family to:

  • Help them understand the health risks of BWS or isolated lateralized overgrowth
  • Review what cancer screening tests are available
  • Find out if other family members should consider genetic testing
  • Help with decisions about genetic testing before or during pregnancy

Genetic testing does not always reveal changes on chromosome 11p15 for all people with these conditions. This is because researchers do not yet fully understand all the genetic causes of this condition. If no changes are found, the child could still have either BWS or isolated lateralized overgrowth. So, all children who have a clinical diagnosis of these conditions should get the same medical management, regardless of genetic test results.

Genetic testing before or during pregnancy

Parents may choose to do prenatal testing to find out if a pregnancy is affected with a known CDKN1C mutation or because of an abnormality of chromosome 11p15. Testing may take place either before pregnancy occurs or during pregnancy.

You should work with a genetic counselor to review the pros and cons of the test. The genetic counselor can also help you prepare for the test results.

Testing before pregnancy is called preimplantation genetic testing (PGT). This type of genetic testing is done along with in vitro fertilization (IVF). PGT tests embryos for the chromosome change that causes these conditions. Methylation defects cannot be detected on PGT. After the embryos are tested, they place them into the uterus.

Testing during pregnancy can help providers see if a pregnancy has the known cause of BWS or isolated lateralized overgrowth. A health care provider gathers cells from the pregnancy in 1 of 2 ways:

  • Chorionic villus sampling (CVS) is done during the first 3 months of pregnancy (1st trimester).
  • Amniocentesis is done after the first 3 months of pregnancy (2nd trimester or later).

After tissue collection, the lab checks the sample for the cause of BWS or isolated lateralized overgrowth. Both tests carry minor risks. Discuss risks with an experienced care provider or genetic counselor.

Special concerns for genetic testing

Take time to think carefully about the benefits and risks of genetic testing. Speak with a genetic counselor before testing. If you decide to get tested, talk with your health care provider or genetic counselor about your results so you can understand what they mean.

Sometimes, children or adults feel sad, anxious, or angry to learn they have this condition. Parents may feel guilty if they pass on gene changes that cause it. Some people with gene changes linked to BWS may have trouble getting disability coverage, life insurance, or long-term care insurance in some states.

Read more information about genetic discrimination.

Monitoring and follow-up care for Beckwith-Wiedemann syndrome or isolated lateralized overgrowth

Children with BWS or isolated lateralized overgrowth have a higher risk of cancer. It is important to monitor children’s health and help them adopt healthy habits. They need to have regular physical checkups and screenings. That way, a health care team can find any cancer early and at the most treatable stage.

Cancer screening for those with BWS or isolated lateralized overgrowth

It is important for children with BWS or isolated lateralized overgrowth to have regular screenings for cancer and other health issues. These children have a higher risk of developing Wilms tumor and hepatoblastoma. They also have a small increased risk of developing other types of cancers. Most of these cancers can be cured with proper treatment if they are found early.

Screening is recommended for all children with this condition. The goal of screening is to find and treat tumors early for the best outcome.

The following screenings are recommended for children with BWS or isolated lateralized overgrowth:

  • Yearly physical exams by a health care provider who knows these syndromes well.
  • Ultrasound exams of the abdomen (belly). These exams start when the child is an infant. They are repeated every 3 months until the child reaches age 8. Until age 4, the ultrasound exam includes views of the liver, kidneys, and other internal organs. After age 4, the risk of cancer in the liver or other internal organs drops dramatically. After this age, the exam focuses on the kidneys.
  • A blood test to check the levels of alpha-fetoprotein (AFP). AFP is a protein that is released by liver cancer cells. Checking levels of AFP in the blood can help screen for liver cancer. Levels are checked beginning when the child is an infant. They are repeated every 6 to 12 weeks until the child reaches the age of 4.

The recommended screenings may change over time as health care providers learn more about this condition. Discuss all screening options with a health care provider who knows these spectrums well. Because BWS and isolated lateralized overgrowth are complex conditions, it is important to find an experienced health care provider for your child.

Living with Beckwith-Wiedemann syndrome or isolated hemihypertrophy

Problems to watch for

Watch closely for general signs or symptoms that could signal cancer:

  • Pain or enlargement of the belly
  • Blood in the urine
  • Aches, pains, lumps, or swelling that have no clear cause

It is important to seek medical help if any unusual symptoms occur.

Maintain a healthy lifestyle

Habits that will help you maintain a healthy lifestyle include:

  • Eat a healthy diet with lots of fruits and vegetables.
  • Get regular exercise.
  • Avoid smoking or using tobacco products.
  • Avoid secondhand smoke.
  • Avoid excess sun exposure and always wear sunscreen, a hat, and protective clothing when out in the sun.

Beckwith-Wiedemann syndrome or isolated lateralized overgrowth care at St. Jude

The St. Jude Cancer Predisposition Program is dedicated to diagnosing and screening children with a genetic predisposition for cancer. Our program offers the best clinical care possible. We engage in cutting-edge research to gain more information about genetic disorders and cancer, and to improve the care and treatment for patients who are affected by these conditions. Learn more about the Division of Cancer Predisposition at St. Jude.

Our genetic counselors, clinicians, genetics nurse practitioners, and research assistants work together to provide patients with:

  • A complete health history
  • A record of cancer that happened over the past 3 generations (family tree or pedigree) to see how diseases were passed down
  • Physical exams to check for genetic disease
  • Confidential genetic counseling and testing
  • Cancer screenings for those with genetic disease to detect and treat cancer as soon as it occurs
  • Recommended cancer treatments and ways to reduce cancer risk
  • Genetic testing for immediate (1st degree) relatives

BWS increases your child’s risk for cancer. 

Related clinical trials

St. Jude offers clinical trials and cancer research studies for children, teens, and young adults who have cancers associated with BWS or isolated lateralized overgrowth. 

Learn more about clinical research at St. Jude

GENETX: Assessing Gene Therapy Communication Needs

Study goal:

To learn more about participants beliefs, attitudes, and questions about gene therapy to help make web-based resources to share information. This could help patients make treatment decisions.


18 to 35 years old with rare genetic diseases

Published results
G4K: Genomes for Kids

Study goal:

The main goal of this study is to learn more about the reasons childhood tumors form and how to treat them better.

TBANK: Collecting, Banking, and Distributing Human Tissue Samples in St. Jude Biorepository

Study goal:

To provide a high-quality repository of tumor and normal samples to facilitate translational research performed by St Jude faculty and their collaborators


All diseases

PG4KDS: Clinical Implementation of Pharmacogenetics

Study goal:

1) Test each patient for hundreds of gene variations that might be important for drug use. All of the gene test results will be in the research laboratory, but as time goes on, the study will evaluate scientific evidence and selectively move test results for a few genes into the medical record if the evidence strongly shows that the result can help in better prescribing of drugs for patients; 2) Estimate how often pharmacogenetic test results are moved from research tests into a patient’s medical record; 3) Use methods to choose which of these tests should be put in the medical record; 4) Use computer-based tools in the electronic medical record to help doctors use gene test results when prescribing drugs; 5) Share feelings and concerns of patients and their families about gene test information being put in their medical record.

SJFAMILY: Study of Cancer in Families

Study goal:

The main purpose of this trial is to learn about the genetic causes of cancer. 


Younger than 50 years old

A statue of children running and holding hands

Seeking treatment at St. Jude

Patients accepted to St. Jude must have a disease we treat and must be referred by a physician or other qualified medical professional. We accept most patients based on their ability to enroll in an open clinical trial.

How to seek treatment

Contact the Physician / Patient Referral Office

Call: 1-888-226-4343 (toll-free) or 901-595-4055 (local)  | Fax: 901-595-4011 | Email: | 24-hour pager: 1-800-349-4334


Learn more

If you have questions about the Genetic Predisposition Clinic and care for Beckwith-Wiedemann syndrome or isolated hemihypertrophy, email our team at

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