Supravalvular aortic stenosis is associated with deletions on chromosome 7 involving the elastin gene in Williams-Beuren syndrome.

Supravalvular aortic stenosis is associated with deletions on chromosome 7 involving the elastin gene in Williams-Beuren syndrome.

• A. Down syndrome
• B. Williams-Beuren syndrome
• C. Turner syndrome
• D. Noonan syndrome

Answer: (B)

Elastin gene deletion on chromosome 7 is the defining genetic change in Williams-Beuren syndrome, and supravalvular aortic stenosis is a hallmark cardiovascular feature. The ELN gene encodes elastin, a key protein in arterial elastic tissue. When one copy is missing (haploinsufficiency), the aortic media develops abnormally, leading to narrowing just above the aortic valve—this is supravalvular, not valvular, stenosis. This deletion on 7q11.23 explains why SVAS is so characteristic in Williams-Beuren syndrome. Other syndromes have different cardiac patterns, helping distinguish them: Down syndrome more often involves endocardial cushion defects; Turner syndrome frequently presents with coarctation of the aorta or a bicuspid aortic valve; Noonan syndrome often features pulmonary valve stenosis or hypertrophic cardiomyopathy.

Elastin gene deletion on chromosome 7 is the defining genetic change in Williams-Beuren syndrome, and supravalvular aortic stenosis is a hallmark cardiovascular feature. The ELN gene encodes elastin, a key protein in arterial elastic tissue. When one copy is missing (haploinsufficiency), the aortic media develops abnormally, leading to narrowing just above the aortic valve—this is supravalvular, not valvular, stenosis. This deletion on 7q11.23 explains why SVAS is so characteristic in Williams-Beuren syndrome.

Other syndromes have different cardiac patterns, helping distinguish them: Down syndrome more often involves endocardial cushion defects; Turner syndrome frequently presents with coarctation of the aorta or a bicuspid aortic valve; Noonan syndrome often features pulmonary valve stenosis or hypertrophic cardiomyopathy.