Williams syndrome (WS), also Williams–Beuren syndrome, is a developmental disorder that affects many parts of the body. This condition is characterized by mild to moderate intellectual disability or learning problems, unique personality characteristics, distinctive facial features, and heart and blood vessel (cardiovascular) problems.
Williams syndrome affects an estimated 1 in 7,500 to 20,000 people.
Williams syndrome is caused by the deletion of genetic material from a specific region of chromosome 7. The deleted region includes more than 25 genes, and researchers believe that a loss of several of these genes probably contributes to the characteristic features of this disorder.
Most cases of Williams syndrome are not inherited, but occur as random events during the formation of reproductive cells (eggs or sperm) in a parent of an affected individual. These cases occur in people with no history of the disorder in their family.
Williams syndrome is considered an autosomal dominant condition because one copy of the altered chromosome 7 in each cell is sufficient to cause the disorder. In a small percentage of cases, people with Williams syndrome inherit the chromosomal deletion from a parent with the condition.
People with Williams syndrome typically have difficulty with visual-spatial tasks such as drawing and assembling puzzles, but they tend to do well on tasks that involve spoken language, music, and learning by repetition (rote memorization). Affected individuals have outgoing, engaging personalities and tend to take an extreme interest in other people. Attention deficit disorder (ADD), problems with anxiety, and phobias are common among people with this disorder.
Young children with Williams syndrome have distinctive facial features including:
- A broad forehead
- A short nose with a broad tip
- Full cheeks
- A wide mouth with full lips
- Small, widely spaced teeth and teeth that are crooked or missing
In older children and adults, the face appears longer and more gaunt.
A form of cardiovascular disease called supravalvular aortic stenosis (SVAS) occurs frequently in people with Williams syndrome. Supravalvular aortic stenosis is a narrowing of the large blood vessel that carries blood from the heart to the rest of the body (the aorta). If this condition is not treated, the aortic narrowing can lead to shortness of breath, chest pain, and heart failure. Other problems with the heart and blood vessels, including high blood pressure (hypertension), have also been reported in people with Williams syndrome.
Additional signs and symptoms of Williams syndrome include:
- Abnormalities of connective tissue (tissue that supports the body’s joints and organs) such as joint problems and soft, loose skin
- Increased calcium levels in the blood (hypercalcemia) in infancy
- Developmental delays
- Problems with coordination
- Short stature
- Medical problems involving the eyes and vision
- Problems with the digestive tract
- Problems with the urinary system
There is no cure for Williams syndrome. Treatment begins with cardiology evaluations, developmental and psychoeducational assessment. Patients should avoiding taking extra calcium and vitamin D, and treating high levels of blood calcium, if present. Blood vessel narrowing can be a significant health problem as well, and is treated on an individual basis. Physical therapy is helpful to patients with joint stiffness. Developmental and speech therapy may also be beneficial.