Cardiovascular disease in Williams syndrome

Williams syndrome (WS), also referred to as Williams-Beuren syndrome (Online Mendelian Inheritance in Man 194050), is a congenital, multisystem disorder involving the cardiovascular, connective tissue, and central nervous systems.1 WS occurs in ≈1 in 10 000 live births2 as a result of the de novo deletion of ≈1.55 to 1.83 Mb on chromosome 7q11.23.3 Familial cases can occur but are far less common than de novo cases.4 The deletion involves 26 to 28 genes, including the ELN gene, which codes for the protein elastin.5 Hemizygosity of the ELN gene coding for elastin has been demonstrated to be responsible for the vascular pathology in WS.6 The remaining 25 to 27 deleted genes contribute to the phenotypic findings in patients with WS and have recently been reviewed in detail elsewhere.5 In 1961, Williams et al7 reported their experience with 4 patients with supravalvar aortic stenosis (SVAS), mental retardation, and abnormal facial features. The following year, Beuren and colleagues8 reported similar findings in 5 patients, and they subsequently reported detailed cardiac and angiographic data from 10 such patients.9 Their findings, combined with other characteristic features, led both groups to theorize that a previously unrecognized syndrome was the likely origin, a theory that led to the eponym Williams-Beuren syndrome. After the reports of Williams et al7 and Beuren et al8 were published, the basis for the diagnosis of WS was the presence of a constellation of distinctive phenotypic characteristics. Genetic analysis at that time was limited essentially to karyotyping and microscopic inspection of individual chromosomes, which Beuren et al9 reported in 3 of their patients. With improved molecular genetics diagnostic techniques, Ewart et al10 used fluorescent in situ hybridization to demonstrate hemizygosity of the ELN locus in patients with WS. …