About Williams Syndrome
The New York Center for Rare Diseases supports the mission and guidelines of the Genetic and Rare Diseases Information Center (GARD). The following information is provided by the NIH.
Summary
Williams syndrome is a genetic condition that affects many parts of the body. Signs and symptoms include mild to moderate intellectual disability; unique personality traits; distinctive facial features; and heart and blood vessel problems. Williams syndrome is caused by a person missing more than 25 genes from a specific area of chromosome 7 (a “deletion”). The loss of these genes contributes to the characteristic features. Although Williams syndrome is an autosomal dominant condition, most cases are not inherited and occur sporadically in people with no family history of Williams syndrome.
Causes
What Causes This Disease?
Genetic Mutations: Williams syndrome is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these.
If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team.
Chromosomal Changes: Williams syndrome is caused by a change in the number of chromosomes a person has, or a change in their structure. Chromosomes are structures within cells that hold all our genes. People usually have 46 chromosomes, 23 come from the biological mother and 23 come from the biological father. Most of the time, chromosomal changes occur randomly in the sperm or egg, but some changes are known to be passed on from parent to child.
Given the known chromosomal changes for this disease, you may want to ask your health care team if chromosome testing is right for you. Results from chromosome testing can confirm or rule out a suspected chromosomal disease or help determine a person’s chance of passing on a disease.
Can This Disease Be Passed Down From Parent to Child?
Yes. It is possible for a biological parent to pass down genetic mutations that cause or increase the chances of getting this disease to their child. This is known as inheritance. Knowing whether other family members have previously had this disease, also known as family health history, can be very important information for your medical team.
There are multiple ways, or patterns, a disease can be inherited depending on the gene(s) involved. Based on GARD’s current data, this disease can be inherited in the following pattern(s):
Autosomal Dominant: Autosomal means the gene involved is located on one of the numbered chromosomes. Dominant means that a child only needs to inherit one copy of the mutated gene, from either biological parent, to be affected by the disease.
People affected by an autosomal dominant disease have a 50% chance of passing on the mutated gene to their biological child.