The majority of individuals with Williams syndrome have some type of heart or blood vessel problem. Typically, there is narrowing in the aorta (producing supravalvular aortic stenos is SVAS), or narrowing in the pulmonary arteries. There is a broad range in the degree of narrowing, ranging from trivial to severe (requiring surgical correction of the defect). Since there is an increased risk for development of blood vessel narrowing or high blood pressure over time, periodic monitoring of cardiac status is necessary.
Some young children with Williams syndrome have elevations in their blood calcium level. The true frequency and cause of this problem is unknown. When hypercalcemia is present, it can cause extreme irritability or “colic-like” symptoms. Occasionally, dietary or medical treatment is needed. In most cases, the problem resolves on its own during childhood, but lifelong abnormality in calcium or Vitamin D metabolism may exist and should be monitored.
Most children with Williams syndrome have a slightly lower birth-weight than their brothers or sisters. Slow weight gain, especially during the first several years of life, is also a common problem and many children are diagnosed as “failure to thrive”. Adult stature is slightly smaller than average.
Many infants and young children have feeding problems. These problems have been linked to low muscle tone, severe gag reflex, poor suck/swallow, tactile defensiveness etc. Feeding difficulties tend to resolve as the children get older.
Many infants with Williams syndrome have an extended period of colic or irritability. This typically lasts from 4 to 10 months of age, then resolves. It is sometimes attributed to hypercalcemia. Abnormal sleep patterns with delayed acquisition of sleeping through the night may be associated with the colic.
Slightly small, widely spaced teeth are common in children with Williams syndrome. They also may have a variety of abnormalities of occlusion (bite), tooth shape or appearance. Most of these dental changes are readily amenable to orthodontic correction.
There is a slightly increased frequency of problems with kidney structure and/or function.
Inguinal (groin) and umbilical hernias are more common in Williams syndrome than in the general population.
Children with Williams syndrome often have more sensitive hearing than other children; Certain frequencies or noise levels can be painful an/or startling to the individual. This condition often improves with age.
Young children with Williams syndrome often have low muscle tone and joint laxity. As the children get older, joint stiffness (contractures) may develop. Physical therapy is very helpful in improving muscle tone, strength and joint range of motion.
Most people with Williams syndrome mild to severe learning disabilities and cognitive challenges. Young children with Williams syndrome often experience developmental delays. Milestones such as walking, talking and toilet training are often achieved somewhat later than is considered normal. Distractibility is a common problem in mid-childhood, which can improve as the children get older.
Older children and adults with Williams syndrome often demonstrate intellectual “strengths and weaknesses.” There are some intellectual areas (such as speech, long term memory, and social skills) in which performance is quite strong, while other intellectual areas (such as fine motor and spatial relations) show significant weakness.