Familial Williams-Beuren syndrome showing varying clinical expression

Abstract

Williams-Beuren syndrome (WBS) is a contiguous gene syndrome that occurs mainly sporadically, with an estimated frequency of 1:13,700 to 1:25,000 [Grimm and Wesselhoeft, 1980; Martin et al., 1984; Udwin, 1990]. The cases of monozygotic twins concordant for WBS and dizygotic twins discordant for the syndrome have been reported. In addition, a few familial cases have been described since 1993. The clinical diagnosis has been supported by molecular genetic findings in only two patients, however. We herein report on two families in which the WBS was inherited in girls from their mothers. All four patients showed the typical hemizygous deletion at 7q11.23 [46,XX, ish,del(7)(q11.23q11.23) (ELN/LIMK1/D7S-613x1, D7S486/D7S522x2)], but the clinical picture was strikingly variable within and between families.

Copy number variants at Williams–Beuren syndrome 7q11.23 region

“…In contrast to the rarity of parental transmission in the WBS Ounap et al 1998;Pankau et al 2001;Sadler et al 1993), and again similar to other duplication syndromes (Brunetti-Pierri et al 2008;Ou et al 2008), there is a high frequency of parental transmission in 7q11.23 duplication patients. Clearly, an important consideration in genetic counseling for the 7q11.23 duplication syndrome is the potential for reduced penetrance and variable expressivity, which has also been reported for wellcharacterized syndromes, such as 22q11.2 microdeletion, where phenotypically mild deletion carriers have escaped clinical recognition until they had children with more severe manifestation (Wilson et al 1992).…”

Severely Calcified Valvular Aortic Stenosis Firstly Diagnosed in Monozygotic Male Twins With Suspected Williams-Beuren Syndrome

“…1,4,5) A dletailed review of the literature did not reveal any records other than valvular calcific aortic stenosis in monozygotic twins. 5) These monozygotic twins were 62 years old and it was found during surgery that one had a native bicuspid and the other a native tricuspid aortic valve.…”

Clinical Manifestations and Molecular Investigation of 50 Patients with Williams Syndrome in the Greek Population

“…The estimated frequency of WS is~1 in 20,000, and the syndrome is mainly sporadic, although there are reports of a few cases following autosomal dominant inheritance (3)(4)(5). WS is one of the contiguous gene syndromes.…”