Williams Syndrome Health Article

Williams Syndrome

A rare genetic disorder first described by J.C.P. Williams of New Zealand, characterized by an abnormality on chromosome seven.

Williams syndrome (WS) is a genetic disorder first described by J.C.P. Williams of New Zealand. It is estimated to occur in about 1 in 20,000 births. Research has indicated that individuals with Williams syndrome have a chromosomal abnormality. A blood test technique known as the fluorescent in situ hybridization (FISH) may be used to detect the deletion of the elastin gene on chromosome #7 of the individual's DNA. This chromosomal abnormality confirms the diagnosis of Williams syndrome. Williams syndrome is present from birth, although it often remains undiagnosed until a later stage of

development. After a child has missed several developmental milestones, the pediatrician may refer him or her to a specialist for diagnosis. Developmental delays that are typical include delay in sitting or walking. Also commonly observed are poor fine motor coordination and delayed development in language (although individuals with WS go on to develop excellent language skills). After reviewing the child's medical and family history, physical condition, and observing the child's behavior, a specialist in birth defects may identify symptoms of Williams syndrome. In many cases, a heart murmur or suspected heart disorder may lead a cardiologist to suspect Williams syndrome, since an estimated 70-75% of people with Williams syndrom have mild to severe cardiovascular problems.

Diagnosis and treatment

Williams syndrome cannot be cured, but the ensuing symptoms, developmental delays, learning problems, and behaviors can be treated. There is a wide variation in the number and severity of symptoms among the individuals with Williams syndrome.

Specialists who can be helpful in diagnosing and treating Williams syndrome include

• cardiologist, to diagnose and prescribe treatment for heart or circulatory problems;
• endocrinologist, to prescribe treatment if elevated calcium levels are detected in infancy;
• pediatrie radiologist, to conduct diagnostic renal and bladder ultrasound tests to diagnose and prescribe treatment for any abnormalities present; and
• occupational therapist, to assess development delays and prescribe a plan for therapy to acquire skills necessary for daily living.

Physical characteristics typical of Williams syndrome include a broad forehead, puffiness around the eyes, stellate eye pattern (in blue-eyed children), upturned nose, depressed nasal bridge, full lips, widely spaced teeth, and small chin. In addition, a child with Williams syndrome often exhibits one or more of these characteristics: sloping shoulders, and elongated neck. Many individuals with Williams syndrome have heart disorders, typically supravalvular aortic stenosis (narrowing) and pulmonary stenosis. Kidney and bladder problems are also common. Poor muscle tone and problems with the skeletal joints become evident as a person with Williams syndrome moves into adolescence.

Infancy and toddlerhood

Williams syndrome babies typically have low weight at birth, and are often diagnosed as failure to thrive. Elevated levels of calcium in the blood (hypercalcemia) may develop in infancy, but it usually is resolved within the first two years. Digestive system symptoms such as vomiting, constipation, and feeding difficulties may contribute to a misdiagnosis in the first months after birth. The infant may not be able to settle in a normal sleep pattern, and may seem to be extremely sensitive to noise (hyperacusis or sensitive hearing), exhibiting agitation or distress when exposed to high-pitched sounds, such as electrical appliances, motors, and loud bangs. This sensitivity most often goes away or diminishes greatly.