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Williams syndrome is caused by a microdeletion in the chromosomal region 7q11.23. The deleted genes included the elastin gene. The typical vasculopathy consists of progressive supravalvular aortic stenosis and nonprogressive or improving pulmonary artery stenosis. Other lesions may include aortic arch obstructions and involvement of innominate or carotid arteries, localised coarctation, and abnormalities of mitral and aortic valves. The diagnosis can be confirmed by demonstrating hemizygosity for the elastin gene by fluorescence in situ hybridisation (FISH). The cardiovascular manifestations have been described in a large retrospective follow up study in Finland (M Eronen and colleagues.
The study included 75 patients aged 0.3–76 years (median 22.7 years) with Williams syndrome confirmed clinically and by FISH. Neonatal manifestations recorded in hospital records consisted of a heart murmur in 28 patients, heart failure in four, cyanosis in two, and absent femoral pulses in one. Twenty-seven of these 35 neonates had structural cardiovascular disease. Altogether 44 of the 75 patients had structural cardiovascular disease demonstrated at some time.
Cardiovascular disease was diagnosed in infancy in 23 patients. Twenty-one of these infants had supravalvular aortic stenosis (6), pulmonary artery stenosis (4), or both (11), and five with both also had coarctation, hypoplastic aortic arch, and hypertrophic cardiomyopathy. One infant had cardiomyopathy alone and one had the tetralogy of Fallot. Fourteen of these infants needed heart surgery or balloon dilatation either in infancy or later. Two died.
Fourteen children had a cardiovascular diagnosis made between the ages of 1 and 15 years. Eleven of these had supravalvular aortic stenosis alone, two had pulmonary artery stenosis alone, and one had a mitral valve defect. Three of the patients with supravalvular aortic stenosis had surgery at ages 8,11, and 45 years. None of these 14 children died during follow up.
Seven patients were older than 15 years when a cardiovascular diagnosis was made. The diagnoses were supravalvular aortic stenosis alone (3), aortic valve defect (2), mitral valve defect (1), and both supravalvular aortic stenosis and mitral valve defect (1). None of these patients had a cardiac intervention but three died. Two of the three cases of supravalvular aortic stenosis alone were diagnosed only at autopsy. Twenty-three of 42 patients over the age of 15 years were hypertensive and 14 of these were treated with antihypertensive drugs.
Cardiovascular disease associated with Williams syndrome may be diagnosed at any age but most commonly in infancy. Surgery or other procedures are often necessary. Hypertension is common in adults with the syndrome.