Williams syndrome is caused by the spontaneous deletion of 26-28 genes on chromosome #7 at the time of conception.  The deletion can occur in either the egg or the sperm. It is likely that the elastin gene In most families, the child with Williams syndrome is the only one to have the condition in his or her entire extended family. 

WS affects 1 in 10,000 people worldwide – an estimated 20,000 to 30,000 people in the United States. It is known to occur equally in both males and females and in every culture.

Children with Williams syndrome tend to be social, friendly, and endearing.  

But there are major struggles as well. Mild to life-threatening cardiovascular problems can be present at birth or become evident while children are still infants and toddlers. Children with WS need costly and ongoing medical care and early interventions (such as speech, physical and occupational therapy) to help overcome developmental delays. As they grow, children struggle with things like spatial relations, numbers, abstract reasoning, and executive functions, which can make daily tasks a challenge. As adults, most people with Williams syndrome will need supportive housing to live to their fullest potential. However,  adults with Williams syndrome contribute to their communities as volunteers or paid employees; often working at assisted living homes for senior citizens, hospitals and libraries, as store greeters or veterinary aides, and more. Both employment and housing opportunities for individuals with Williams syndrome are increasing and improving annually.   

Due to their friendly nature and need for companionship, opportunities for social interaction are important to those with Williams syndrome throughout their lives. However, people with Williams syndrome often don’t process nuanced social cues often making it difficult to form lasting relationships. As people with Williams syndrome mature – beyond the structure of school and family activities – they often experience intense isolation which can lead to increased anxiety and depression.   

There are many features common to those with Williams syndrome. The elastin deletion is responsible for many of the physical features. Other medical and developmental problems are likely caused by the deletions of the additional genetic material near the elastin gene on chromosome #7. However, every child is an individual - the number of features present, and which features are present varies from child to child, even though more than 95% of individuals have an identical 26-28 gene deletion.