An Overview of Williams Syndrome

Table of Contents
View All
Table of Contents

Williams Syndrome is a genetic disorder characterized by developmental delays and certain medical conditions such as heart problems and low muscle tone. People with Williams syndrome also often have advanced language skills, outgoing personalities, and a love for music. It is caused by a chromosome abnormality and affects how a person grows and develops.

Pediatrician checking height of girl in examination room
Hero Images / Getty Images


People with Williams syndrome often have certain facial characteristics that are distinct and unique to the syndrome. Young children tend to have broad foreheads, short noses, full cheeks, and a wide mouth with full lips. Once teeth come in, they may be crooked, small, widely spaced, or missing. Older children and adults may have faces that appear long and gaunt.

Other than outward appearance, people with Williams syndrome can have a variety of differences from their typically developing peers. They may experience developmental delays and learning difficulties.

Common medical issues include:

  • Cardiovascular problems: such as supravalvular aortic stenosis (SVAS) and high blood pressure
  • Hypercalcemia: high levels of calcium in the blood in infants
  • Low birth weight or slow weight gain
  • Feeding difficulty
  • Colic/irritability during infancy
  • Dental abnormalities
  • Kidney abnormalities: some people with Williams syndrome have problems with kidney structure and/or function
  • Hernias: inguinal and umbilical
  • Sensitivity to sound
  • Low muscle tone


Genetically, Williams syndrome is caused by a deletion of 26-28 genes on the 7th chromosome. This spontaneous deletion occurs either in the egg or the sperm and is believed to be present at the time of conception. Williams syndrome is estimated to occur in one out of every 7500 to 10,000 people.

In most cases, Williams syndrome occurs randomly with no family history of the disorder. However, a person with Williams syndrome has a 50% chance of passing it on to their children.


If a physician or healthcare provider suspects a child may have Williams syndrome due to physical characteristics, they should order genetic testing to confirm the diagnosis. There are two tests that can be performed to provide a diagnosis of Williams syndrome.

FISH Testing

This test is performed by drawing 5mL of blood from the baby or child with suspected Williams syndrome. Fluorescent in situ hybridization (FISH) testing "is a type of specialized chromosome analysis utilizing specially prepared elastin probes. If a patient has two copies of the elastin gene (one on each of their chromosomes #7), they probably do not have Williams syndrome. If the individual only has one copy, the diagnosis of Williams syndrome will be confirmed," according to the Williams Syndrome Association.

The results of this test may take several weeks to come back and it is only performed at specialized labs, so a healthcare provider will need to ensure the test can be done before the blood is drawn and sent off.

Microarray Testing

The other type of genetic testing that can be performed is a chromosomal microarray which uses markers to determine if there are missing or extra pieces of DNA anywhere on a person's chromosomes.

These tests are only performed in certain labs as well, so a healthcare provider will need to ensure they are ordering the correct test. The turnaround time is typically 2-4 weeks for this type of test as well.

Therapy and Treatment

Williams syndrome is a genetic disorder and there is no cure. However, there are many therapies and resources available to help support children and families. They can help babies, children, and adults with skills that may be difficult, allowing them greater independence and inclusion in school and community settings.

Most children with Williams syndrome can benefit from physical therapy, occupational therapy, and speech therapy to help with developmental delays and motor skills. In the United States, there are early intervention programs that provide these therapies as needed with a physician's referral until the age of three.

After the age of three, these services are typically provided through the local school system. There are many private therapy services available as well that may or may not be covered by health insurance. Other therapies that may help people with Williams syndrome include music therapy, hippotherapy (horseback riding), aquatic therapy, and sound therapy.

Once a child with Williams syndrome enters the school system, they typically qualify for an Individualized Education Plan (IEP). Families work with teachers, school staff, and therapists to determine individual educational and developmental goals for the child. Once a child with Williams syndrome reaches an age or a cognitive level where they can meaningfully participate, they will often be included in these meetings and decisions as well.


Receiving a diagnosis of Williams syndrome for a child can be life-altering. Life will likely look much different than anticipated. However, that change does not have to be a bad one.

Although there may be challenges in raising a child with Williams syndrome, there will be many positive aspects as well. Parents, guardians, and siblings of children with Williams syndrome often report that their lives are better than they expected.

If a child has been recently diagnosed, focus on immediate medical issues first. If a child has any heart or other medical conditions that need to be addressed, make those your priority.

Once the child is physically stable, you can focus on the emotional and mental adjustments that you may need to make to cope. Many parents or guardians of children with disabilities report that they experienced a period of grief after their child's diagnosis, which is completely normal.

Talking to other parents or guardians of children and adults with Williams syndrome may be helpful. Joining a local or online support group is helpful to many as well. When you are ready, finding people that have experience with Williams syndrome is often the best resource.

Learn what you can about the condition because you will need to educate others about the child's strengths and weaknesses. The Williams Syndrome Association has helpful information for parents, guardians, family members, caregivers, and healthcare providers.

A Word From Verywell

If you have recently received a diagnosis of Williams syndrome for a child, know that it will take time to adjust but you are not alone. There are many resources and other families that have experienced life in your shoes before and things will likely get better.

Although there are no guarantees in life, raising a child with Williams syndrome may not be as difficult as it initially seems. Don't be afraid to reach out for help when you need it and take advantage of the resources available to you.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  • What is Williams Syndrome? Williams Syndrome Association. Published January 26, 2010.
  • Miller DT, Adam MP, Aradhya S, et al. Consensus Statement: Chromosomal Microarray Is a First-Tier Clinical Diagnostic Test for Individuals with Developmental Disabilities or Congenital Anomalies. Am J Hum Genet. 2010;86(5):749-764. doi:10.1016/j.ajhg.2010.04.006

  • Williams syndrome. Genetics Home Reference.

By Kristina Duda, RN
Kristina Duda, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention.