XL Williams-Beuren consists of an orange-labeled probe hybridizing to the ELN/LIMK1 gene region at 7q11.23 and a green-labeled probe hybridizing to a region at 7p11.2.

Probe maps are created in accordance with the intended purpose of the product. Solid colored bars do not necessarily indicate that the probe fully covers the indicated genomic region. Therefore, caution is advised when interpreting results generated through off-label use. Probe map details based on UCSC Genome Browser GRCh37/hg19. Map components not to scale. Further information is available on request.

Williams-Beuren syndrome (WBS) is a contiguous gene deletion syndrome with an estimated prevalence of 1:7.500 to 1:25.000 newborns. WBS phenotype is complex, age-dependent and varies between individuals. Newborns have characteristic ´elfin-like´ facial features with full cheeks, small head, flat nasal bridge, broad forehead, prominent open mouth, broad nose and puffiness around eyes and lips. Patients have a wide spectrum of features affecting the cardiovascular system, development and cognition, teeth, endocrine system, gastrointestinal tract, acoustic perception, nose and throat. One of the most fatal and characteristic complications is supravalvular aortic stenosis (SVAS).
WBS is associated with a chromosomal microdeletion in region 7q11.23. The common critical region is about 1.6Mb in size and contains more than 20 genes, including ELN (elastin) and LIMK1 (LIM domain kinase 1). Haploinsufficiency of ELN correlates with cardiovascular problems and is responsible for the SVAS phenotype of WBS patients. Deletions in region 7q11.23 are a consequence of non-allelic homologous recombination between low copy repeat elements flanking the WBS deleted region. Most WBS cases are sporadic, only few cases are transmitted vertically.

Clinical Applications

• Microdeletion Syndrome (MicroDel)

XL Williams-Beuren hybridized to lymphocytes. One normal metaphase is shown.

• Wu et al (1998) Am J Med Genet 78:82-89
• Bayés et al (2003) Am J Hum Genet 73:131-151
• Jurado (2003) Horm Res 59 (suppl 1):106-113