Heart and Blood Vessel Issues in Williams Syndrome
A common health problem is cardiovascular disease, with a narrowing in the aorta (Supravalvar Aortic Stenosis - SVAS) being particularly common. This occurs in approximately 80% of individuals. The degree of narrowing ranges from minor to severe and can worsen over time, particularly in the first 5 years of life. In some instances, surgical correction may be required. If untreated, it can result in an increase in heart pressure, and possibly cardiac failure.
Additionally, the narrowing of the pulmonary arteries (Peripheral Pulmonary Stenosis - PPS), is quite common in infancy, however it usually improves over time.
Individuals may also experience elevated blood calcium levels, known as hypercalcemia, the cause of which is unknown. It can cause irritability and abnormal sleep patterns. This condition is usually treated with medication.