期刊名称：Revista Virtual de Estudos da Linguagem - ReVEL
电子版ISSN：1678-8931
出版年度：2005
卷号：3
期号：5
出版社：Gabriel de Ávila Othero
摘要：The Williams-Beuren syndrome (Williams et al. 1961; Beuren et al. 1962) is included in the so called “rare diseases”2. It is a genetic disease caused by the microdeletion in chromosome 7 in the band q.11.23 (Ewart et al. 1993). A map of 17 genes deleted in this region has been traced (Osborne et al, 2001). Its incidence is 1 per each 25.000 new borns. Deletions in the same area seem to be present in 98% of the population with Williams syndrome, that is called the “clasical pattern” or “common Williams syndrome” (Mervis et al. in press); nevertheless, there is another 2% which present variations that can be explained not by a deletion in the genetic pattern, but by an inverted genetic pattern that results in an atypical Williams syndrome (Morris and mervis, 2000); atypical Williams syndrome share most of the particular characteristics the Williams syndrome present: mental retardation, attentional deficits, facial features and the pattern of behaviour; albite Tassabehji et al. (1999) have seen that there are patients with the chromosomical deletion who do not present the typical dismorphic features as the Williams syndrome subjects do.
