Williams syndrome

Definition

Williams syndrome is a rare genetic disorder that can lead to problems with development.

Alternative Names

Williams-Beuren syndrome

Causes, incidence, and risk factors

Williams syndrome is a rare condition caused by missing genes. Parents may not have any family history of the condition. However, a person with Williams syndrome has a 50% chance of passing the disorder on to each of his or her children. The cause usually occurs randomly.

Williams syndrome occurs in about 1 in 8,000 births.

One of the 25 missing genes is the gene that produces elastin, a protein that allows blood vessels and other tissues in the body to stretch. It is likely that having only one copy of this gene results in the narrowing of blood vessels seen in this condition.

Symptoms

• Delayed speech that may later turn into strong speaking ability and strong learning by hearing
• Developmental delay
• Easily distracted, attention deficit disorder (ADD)
• Feeding problems including colic, reflux, and vomiting
• Inward bend of the small finger (clinodactyly)
• Learning disorders
• Mild to moderate mental retardation
• Personality traits including being very friendly, trusting strangers, fearing loud sounds or physical contact, and being interested in music
• Short compared to the rest of the person's family
• Sunken chest (pectus excavatum)
• Unusual appearance of the face
  • Flattened nasal bridge with small upturned nose
  • Long ridges in the skin that run from the nose to the upper lip (philtrum)
  • Prominent lips with an open mouth
  • Skin that covers the inner corner of the eye (epicanthal folds)
  • Partially missing teeth, defective tooth enamel, or small, widely spaced teeth

Signs and tests

Signs include:

• Blood vessel narrowing including supravalvular aortic stenosis, pulmonary stenosis, and pulmonary artery stenosis
• Farsightedness
• High blood calcium level (hypercalcemia) that may cause seizures and rigid muscles
• High blood pressure
• Slack joints that may change to stiffness as patient gets older
• Unusual pattern ("stellate" or star-like) in iris of the eye

Tests for Williams syndrome:

• Blood pressure check
• Blood test for missing chromosome (FISH test)
• Echocardiography combined with Doppler ultrasound
• Kidney ultrasound

Treatment

There is no cure for Williams syndrome. Avoid taking extra calcium and vitamin D. Treat high levels of blood calcium, if present. Blood vessel narrowing can be a significant health problem and is treated based on its severity.

Physical therapy is helpful to patients with joint stiffness. Developmental and speech therapy can also help these children (for example, verbal strengths can help make up for other weaknesses). Other treatments are based on a patient's symptoms.

It can help to have treatment coordinated by a geneticist who is experienced with Williams syndrome.

Support Groups

Williams Syndrome Foundation -- www.wsf.org

Williams Syndrome Association -- www.williams-syndrome.org

Expectations (prognosis)

About 75% of those with Williams syndrome have some mental retardation.

Most patients will not live as long as normal, due to complications.

Most patients require full-time caregivers and often live in supervised group homes.

Complications

• Calcium deposits in the kidney and other kidney problems
• Death (in rare cases from anesthesia)
• Heart failure due to narrowed blood vessels
• Pain in the abdomen

Calling your health care provider

Many of the symptoms and signs of Williams syndrome may not be obvious at birth. Call your health care provider if your child has features similar to those of Williams syndrome. Seek genetic counseling if you have a family history of Williams syndrome.

Prevention

There is no known way to prevent the genetic problem that causes Williams syndrome. Prenatal testing is available for couples with a family history of Williams syndrome who wish to conceive.