Overview Of Williams-Beuren Syndrome (WBS)
Williams-Beuren syndrome (WBS) is a rare developmental disorder that affects multiple parts of the body. This condition is characterized by mild to moderate learning problems or intellectual disabilities, unique personality characteristics, distinctive facial features, and cardiovascular problems.
People with Williams-Beuren syndrome usually have difficulty with visual-spatial tasks. These tasks include activities such as drawing and puzzles. However, they tend to do well on tasks that involve spoken language, music, and learning by repetition. Individuals with this condition also have friendly, outgoing personalities, and tend to adopt an extreme interest in other people. In the same vein, attention deficit disorder (ADD), issues with anxiety, and phobias are common.
Young children with Williams-Beuren syndrome have distinctive facial features. For example, these features include a broad forehead, a short nose with a broad tip, full cheeks, and a wide mouth with full lips. Many also have dental problems such as wide spaces and crooked, missing, or small teeth. In older children and adults, the face appears longer and more gaunt.
Supravalvular aortic stenosis (SVAS), a form of cardiovascular disease, often occurs in people with Williams syndrome. In SVAS, a narrowing of the aorta occurs. If the patient does not treat this condition, the aortic narrowing can result in chest pain, shortness of breath, and heart failure. People with Williams-Beuren syndrome also report other heart and blood vessel problems, including high blood pressure.
Other signs and symptoms of this condition include abnormalities of the body’s connective tissue. For example, this includes joint problems and soft, loose skin. Affected people may experience hypercalcemia in infancy, or increased levels of calcium in the blood, developmental delays, problems with coordination, and short stature. Medical issues involving the eyes, vision, digestive tract, and urinary system are also possible.
Commonly Associated With
- Beuren syndrome
- Elfin facies syndrome
- Elfin facies with hypercalcemia
- Hypercalcemia-supravalvar aortic stenosis
- Infantile hypercalcemia
- Supravalvar aortic stenosis syndrome
- Williams-Beuren syndrome
Causes OfWilliams-Beuren Syndrome (WBS)
Williams-Beuren syndrome is caused by the deletion of up to 28 genes from a specific region of chromosome 7. And, researchers believe that a loss of these genes likely contributes to the characteristic features of this disorder.
Some of the genes that are typically deleted in people with Williams-Beuren syndrome include CLIP2, ELN, GTF2I, GTF2IRD1, and LIMK1. Similarly, professionals associate the loss of the ELN gene with certain characteristic features of this condition. This includes the connective tissue abnormalities and cardiovascular disease (specifically supravalvular aortic stenosis) present in many people with Williams Syndrome.
In addition, studies indicate that the deletion of CLIP2, GTF2I, GTF2IRD1, LIMK1, and perhaps other genes may help explain the characteristic challenges with visual-spatial tasks, unique behavioral characteristics, and other cognitive difficulties seen in this condition. Moreover, the deletion of GTF2IRD1 may also contribute to the distinctive facial features associated with Williams-Beuren syndrome.
In people with Williams-Beuren syndrome, researchers believe that the risk of developing hypertension is related to the presence or absence of the NCF1 gene on chromosome 7. For example, when the NCF1 gene is included in the part of the chromosome that is deleted, affected individuals are less likely to develop hypertension. Therefore, the loss of this gene looks to be a protective factor. When the NCF1 gene is not deleted in People with Williams syndrome, they have a higher risk of developing hypertension.
In regards to the signs and symptoms of Williams-Beuren syndrome, the connection between other genes in the deleted region of chromosome 7 is currently under investigation (or is presently not known).
Symptoms OfWilliams-Beuren Syndrome (WBS)
Symptoms of Williams-Beuren syndrome include:
- Feeding problems, such as colic, reflux, and vomiting
- An Inward bend of the small finger
- A sunken chest
- Heart disease or blood vessel problems
- Developmental delay
- Mild to moderate intellectual disability and learning disorders
- Delayed speech that may later turn into strong speaking ability and strong learning by hearing
- Easily distracted, attention deficit hyperactivity disorder (ADHD)
- Personality traits including being very friendly, trusting strangers, fearing loud sounds or physical contact, and an interest in music
- Short, compared to the rest of the person’s family
The face and mouth of someone with Williams-Beuren syndrome may show the following:
- A flattened nasal bridge with small upturned nose
- Long ridges in the skin that run from the nose to the upper lip
- Prominent lips with an open mouth
- Skin that covers the inner corner of the eye
- Partially missing teeth, defective tooth enamel, or small, widely spaced teeth
Exams & Tests
Signs include the following:
- Narrowing of some blood vessels
- Dental problems, including teeth that are widely spaced
- High blood calcium level that may cause seizures and rigid muscles
- High blood pressure
- Loose joints that may change to stiffness as the person ages
- Unusual star-like pattern in iris of the eye
Tests for Williams-Beuren syndrome include:
- Checking blood pressure
- Blood test for a missing piece of chromosome 7 (FISH test)
- Blood and urine tests for calcium level
- Echocardiography combined with Doppler ultrasound
- Kidney ultrasound
Treatment Of Williams-Beuren Syndrome (WBS)
No cure currently exists for Williams-Beuren syndrome. As a result, treatment is based on how severe it is. Avoid taking extra calcium and vitamin D and treat high blood calcium if it occurs. Further, narrowing of the blood vessels can be a major health problem. For people with joint stiffness, physical therapy is helpful. Developmental and speech therapy can also help as having strong verbal skills can make up for other weaknesses. Other treatments are based on the person’s symptoms. Subsequently, it can help to have a geneticist with experience in Williams syndrome coordinate a person’s treatment.
Williams-Beuren syndrome affects roughly 1 in 7,500 to 10,000 individuals. Certainly, most cases of Williams syndrome are not inherited. Instead, they occur as random events during the formation of reproductive cells (eggs or sperm) in a parent of an affected person. These cases arise in people with no family history of the disorder.
In short, Williams-Beuren syndrome is considered an autosomal dominant condition. This is because one copy of the altered chromosome 7 in each cell is sufficient enough to cause the disorder. In a small percentage of cases, people with this condition inherit the chromosomal deletion from a parent with the disorder.