Williams Syndrome

What Is Williams Syndrome?

Williams syndrome is a genetic condition that occurs in about 1 in 7,500 people. In most cases, the genetic change that causes Williams syndrome occurs de novo, meaning it appears for the first time in the person affected by the condition.

The condition impacts many different body systems, although the symptoms, medical concerns and their severity vary widely. The heart and blood vessels (cardiovascular system) and digestive tract (gastrointestinal system) are among the most affected systems in the body. In addition, children with Williams syndrome may have developmental delays and individuals often have a specific learning profile.  

What Causes Williams Syndrome?

Williams syndrome is caused by a missing segment of genetic material (DNA) in one of our chromosomes. Chromosomes come in pairs and humans have 23 pairs. We inherit one chromosome of each pair from our mother and the other from our father. Missing DNA is called a deletion.

Our genes are made of DNA, which is packaged into the chromosomes. Each gene has instructions for making a specific product our body needs to grow and function. When some of the instructions are missing, as in a deletion, this can cause medical concerns.

In Williams syndrome, the deletion occurs in a specific region or location on chromosome number 7, designated 7q11.23. This region is often referred to as the Williams-Beuren syndrome critical region (WBSCR) or the Williams syndrome critical region (WSCR). This region spans 26 to 28 different genes, and the loss of the DNA instructions for making these gene products causes the phenotype (or symptoms) associated with Williams syndrome.

Researchers are working to better understand the impact of each of the genes in this region. To date, one of the best understood genes associated with Williams syndrome is the ELN gene. This gene has instructions for a protein called elastin which gives connective tissue throughout the body its elastic and stretchy properties. Connective tissue supports and gives structure to other tissues and organs, including skin, joints and blood vessels. Having only one copy of this gene is felt to cause some of the signs and symptoms seen in someone with Williams syndrome.

What Are Signs & Symptoms of Williams Syndrome?

Although signs and symptoms vary, they may include:

  • Heart and blood vessel (cardiovascular) disease
  • Digestive (gastrointestinal) problems
  • High levels of calcium in the blood (hypercalcemia)
  • Feeding difficulties
  • Short height
  • Low muscle tone
  • Joint problems
  • Early developmental delays
  • Unique personality traits

How Is Williams Syndrome Diagnosed?


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Williams syndrome may be suspected based on a child’s medical history, but genetic testing is necessary to confirm a diagnosis. For example, a cardiologist may suspect Williams syndrome if a child is born with supravalvular aortic stenosis, which is a narrowing of the major blood vessel of the body (the aorta), but genetic testing would be needed to confirm the diagnosis.

Fluorescent in Situ Hybridization (FISH) Test

The first diagnostic genetic test for Williams syndrome was a fluorescent in situ hybridization (FISH) test. This test uses a special fluorescent probe that binds to the ELN gene. A control probe is also used to be sure the test is working correctly. FISH can detect if someone is missing one copy of the ELN gene, which indicates a deletion in the critical region on chromosome 7.

Chromosome Microarray

More and more today, the genetic test used to diagnose Williams syndrome is called a chromosome microarray. This test can pinpoint the deletion on chromosome number 7 that is characteristic of Williams syndrome and also tells us the size of the deletion. Most people with Williams syndrome have chromosome deletions of similar size, yet others have smaller or bigger deletions which encompass a fewer or a greater number of genes. This may be important information in the future as we better understand the roles that these individual genes play in the body.

How Is Williams Syndrome Treated?

There is no cure for Williams syndrome, yet there are published, evidence-based healthcare guidelines. Treatment is lifelong and focuses on the management of symptoms. This is best achieved with a multidisciplinary healthcare team. Treatment plans and periodic medical screenings are based on the specific needs of each individual and should follow the age-based guidelines published by the American Academy of Pediatrics.  

Make an Appointment

Our Williams syndrome care team is proud to partner with the Williams Syndrome Association as we create a new program dedicated to the care and support of individuals with Williams syndrome and their families. Please join us as we build the only specialized Williams syndrome clinic in the Chicagoland area.

To schedule an appointment with Joshua Baker, DO, and genetic counselor Sarah Jurgensmeyer, MS, CGC, for the Williams syndrome clinic, please call the Division of Genetics at 312.227.6120.   

Resources & Support

For additional information on Williams syndrome, please visit the websites below:

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