Mutational mechanisms of Williams-Beuren syndrome deletions.

ABSTRACT: Williams-Beuren syndrome (WBS) is a segmental aneusomy syndrome that results from a heterozygous deletion of contiguous genes at 7q11.23. Three large region-specific low-copy repeat elements (LCRs), composed of different blocks (A, B, and C), flank the WBS deletion interval and are thought to predispose to misalignment and unequal crossing-over, causing the deletions. In this study, we have determined the exact deletion size and LCR copy number in 74 patients with WBS, as well as precisely defined deletion breakpoints in 30 of them, using LCR-specific nucleotide differences. Most patients (95%) exhibit a 1.55-Mb deletion caused by recombination between centromeric and medial block B copies, which share approximately 99.6% sequence identity along 105-143 kb. In these cases, deletion breakpo

SUBMITTER: Bayes M 

PROVIDER: S-EPMC1180575 | biostudies-literature | 2003 Jul

REPOSITORIES: biostudies-literature