Williams Syndrome

Hallie Omohundro

Synonyms

  • Beuren Syndrome
  • Early Hypercalcemia Syndrome with Elfin Facies
  • Elfin Facies with Hypercalcemia
  • Hypercalcemia-Supravalvar Aortic Stenosis
  • WBS
  • Williams-Beuren Syndrome
  • WMS

General Description

Williams syndrome is a rare genetic disorder characterized by growth delays before and after birth, short stature, a varying degree of mental deficiency, and distinctive facial features that typically become more pronounced with age. Such characteristic facial features may include a round face, full cheeks, thick lips, a large mouth that is usually held open, and a broad nasal bridge with nostrils that flare forward. Affected individuals may also have unusually short eyelid folds , flared eyebrows, a small lower jaw, and prominent ears. Dental abnormalities may also occur including abnormally small, underdeveloped teeth with small, slender roots. Williams syndrome may also be associated with heart defects, abnormally increased levels of calcium in the blood during infancy, musculoskeletal defects, and/or other abnormalities.

Signs and Symptoms

Some children with Williams syndrome may have a low birth weight, feed poorly, and fail to gain weight and grow at the expected rate. Symptoms such as vomiting, gagging, diarrhea, and constipation are common during infancy. Some affected infants may have elevated levels of calcium in their blood, leading to loss of appetite, irritability, confusion, weakness, easy fatigability, and/or abdominal and muscle pain.

Newborns with Williams syndrome have characteristic “elfin-like” facial features including an unusually small head, full cheeks, an abnormally broad forehead, puffiness around the eyes and lips, a depressed nasal bridge, broad nose, and/or an unusually wide and prominent open mouth. Additional features may include a vertical skin fold on the inner corners of the eyes, a small pointed chin, prominent ears, and/or an unusually long vertical groove in the center of the upper lip. Some infants with Williams Syndrome may have dental abnormalities including malformed teeth, small teeth, and upper and lower teeth that do not meet properly.

A star-like pattern in the iris of the eye may be apparent in about 50 percent of children with this disorder. Affected infants may also experience inward deviation of the eyes and farsightedness.

Children with Williams syndrome are extremely sensitive to sound and may overreact to unusually loud or high-pitched sounds. Chronic middle ear infections are often present.

Motor development may be delayed. The development of secondary sexual characteristics may occur prematurely in children with this disorder. Breast development and menstruation may occur earlier than expected in females with Williams syndrome. Individuals with this disorder may also have an unusually hoarse voice.

Causes

Most cases of Williams syndrome appear to occur spontaneously (sporadically) for unknown reasons. However, some familial cases of the disorder have also been reported. Ongoing research indicates that sporadic and familial Williams syndrome result from deletions of genetic material from adjacent genes (contiguous genes) located on the long arm (q) of chromosome 7 (7q11.23). This chromosomal region has been designated “Williams-Beuren Syndrome chromosome region 1” (WBSCR1).

Affected Populations

Williams syndrome is a rare disorder that affects males and females in equal numbers and infants of any race may be affected. The prevalence of this disorder is approximately one in 10,000-20,000 births in the United States.

Related Disorders

Noonan syndrome

Idiopathic infantile hypercalcemia

Leprechaunism

Pulmonary artery stenosis

Diagnosis

The diagnosis of Williams syndrome may be confirmed by a thorough clinical evaluation that includes a detailed patient history and specialized blood tests that may detect elevated levels of calcium in the blood. Another test, known as fluorescent in situ hybridization [FISH], may be used to determine whether a deletion of one elastin gene on chromosome 7 is present.

Standard Therapies

Infants with Williams syndrome who have elevated levels of calcium in their blood may be placed on a diet that restricts the intake of vitamin D. Calcium intake may also be restricted.

Some children with Williams Syndrome who have severe heart defects may require surgical treatment to repair the defect.

Centers for developmentally disabled children and special education services in schools may be beneficial for children with Williams syndrome to reach their personal potential.

Genetic counseling may be of benefit for people with Williams syndrome and their families. Other treatment is symptomatic and supportive.

Supporting Organizations

Williams Syndrom Association

Canadian Association for Williams Syndrome

The Arc

Williams Syndrom Family of Hope

Williams Syndrome Foundation