Differing Microdeletion Sizes and Breakpoints in Chromosome 7q11.23 in Williams-Beuren Syndrome Detected by Chromosomal Microarray Analysis.

Williams-Beuren syndrome (WBS) manifests as supravalvular aortic stenosis, intellectual disability, developmental delay and characteristic facial features. The common WBS deletion region ranges from 1.55 to 1.84 Mb and primarily contains the ELN gene. We analyzed 10 patients diagnosed with 7q11.23 microdeletion syndrome by chromosomal microarray analysis. The clinical features of these patients varied from classic WBS to normal phenotype. All 10 patients exhibited different sizes and breakpoints of chromosome microdeletions ranging from 44 kb to 9.88 Mb. The hemizygosity of the ELN gene was detected in 7 patients, while a normal ELN gene was present in 3 other patients with small deletions. We observed that the phenotypic features of WBS varied in fetuses, children and adults, influenced by the genes, deletion size and breakpoint. Our findings provide more information on the genotype-phenotype correlations of WBS. However, further research is needed to explore the size and breakpoint effect and functions of the genes on chromosome 7q11.23.