Objective: The prevalence and types of various cardiovascular diseases in different age groups as well as the outcomes of cardiac surgery and other interventions were assessed in a population of 75 Williams syndrome (WS) patients aged 4 months to 76 years (median 22.7 years).

Study design: The diagnosis of WS was in each case confirmed by the clinical phenotype and by a FISH test showing elastin hemizygosity. Clinical and operative data were collected from all hospitals where the patients had been treated.

Results: Cardiovascular symptoms were evident in 35 of 75 (47%) WS children at birth. During follow up, 44 of 75 (53%) WS patients were found to have cardiovascular defects. Among them, the definitive diagnosis was made before 1 year of age in 23 (52%) infants, between 1 year and 15 years of age in 14 (32%) children, and older than 15 years of age in 7 (16%) adults. Multiple obstructive cardiovascular diseases were found in six infants. Supravalvular aortic stenosis (SVAS) was diagnosed in 32/44 (73%), pulmonary arterial stenosis (PAS) in 18/44 (41%), aortic or mitral valve defect in 5/44 (11 %) of cases, and tetralogy of Fallot in one (2%) case. Altogether, 17/44 (39 %) underwent surgery or intervention. Surgery was most frequently performed in the infant group (6% v 21% v 0%, p=0.004). After 1 year of age, seven patients underwent SVAS relief and two cases PAS relief. Postoperatively there was no mortality (median follow up time 6.9 years). Arterial hypertension was found in 55% of adults. In three adults, arterial vasculopathy was not diagnosed until necropsy.

Conclusions: Our data indicate the following in WS. Cardiac symptoms are common in neonates. Heart disease diagnosed in infancy frequently requires operation. After 1 year of age, PAS tends to improve and SVAS to progress. Life long cardiac follow up is necessary because of the risks of developing vasculopathy or arterial hypertension.