Williams syndrome is a genetic disorder characterized by mild mental retardation , distinctive facial appearance, problems with calcium balance, and blood vessel disease.
Causes, incidence, and risk factors
Williams syndrome is a genetic disorder characterized by developmental delay, unusual facial appearance, narrowing of the aorta (large artery that leaves the heart) and particular cognitive and personality profiles. It is a rare condition caused by missing genetic material on one copy of chromosome #7. The problem is usually caused by a random mutation, so 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 child. It occurs in about 1 in 20, 000 births. One of the missing genes is the gene that produces elastin, a protein that gives elasticity to blood vessels and other tissues in the body. It is likely that having only one copy of this gene results in the narrowing of blood vessels seen in this condition
Signs and tests
prominent lips with an open mouth flattened nasal bridge with small upturned nose epicanthal folds long philtrum (midline from upper lip margin to lower nose) unusual pattern in iris ("stellate" or star-like) partial absence of the teeth, defective tooth enamel, or small, widely-spaced teeth heart failure (depending on degree of heart defect) high blood calcium level, hypercalcemia , that may cause seizures and muscle rigidity
hypertension (depending on degree of blood vessel narrowing) echocardiography with Doppler (may show blood vessel narrowing) periodic blood pressure check kidney ultrasound (some patients have renal defects) blood test for chromosome deletion that is called a FISH test (genetic defect found in 99% of patients with Williams syndrome) far sightedness
Treatment
There is no cure for Williams syndrome. Supplemental calcium and vitamin D should be avoided. It is important to treat high levels of blood calcium if present. The blood vessel narrowing can be a significant health problems and are treated based on severity. Physical therapy is helpful to patients with joint stiffness. Developmental and speech therapy can also help these children; for example, their verbal strengths can help compensate for other weaknesses. Other treatments are individualized based on a particular patient's symptoms. Coordination of treatment by a geneticist experienced with Williams syndrome can be beneficial.
Support groups
Williams Syndrome Foundation www.wsf.org 949-UCI-7259 Williams Syndrome Association www.williams-syndrome.org 248-541-3630
Expectations (prognosis)
Some degree of mental retardation is found in about 75% of patients with Williams syndrome. Most patients have a shortened life expectancy, due to complications. The majority of patients do not live independently of care givers.
Complications
Blood vessel narrowing can cause heart failure. Elevated calcium can lead to calcium deposits in the kidney and other kidney problems. Abdominal pain is common for a variety of reasons.
Calling your health care provider
Many of the symptoms and signs of Williams syndrome may not be apparent at birth. Call your health care provider if you child has features that might be suggestive of Williams syndrome. Seek genetic counseling if there is a family history of Williams syndrome.
Prevention
There is no known prevention for the random mutation. If there is a family history of Williams syndrome prenatal genetic testing is available.