The XA 21q22 specific probe allows detecting copy number variations for chromosomes 21. The orange labeled probe hybridizes to a region at 21q22 including the DSCR4 (Down syndrome critical region 4).

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.

Numerical aberrations of autosomes 13, 18, 21, and sex chromosomes X and Y account for 95% of birth defects in newborns. FISH applied to uncultured amniocytes provides a method to identify those aberrations much faster than conventional chromosome analysis. It has become a standard to provide preliminary results for the detection of anomalies in less than 12 hours.

Duplications of chromosome bands 21q22.13-q22.2 have been shown to define the smallest region implicated in the causation of Down syndrome.

XA 21q22 was hybridized to normal lymphocytes. A metaphase is shown with orange signals hybridized to 21q22.

• Tepperberg et al (2001) Prenat Diagn 21:293-301
• Ronan et al (2007) J Med Genet 44:448-451
• Korbel et al (2009) Proc Natl Acad Sci USA 106:12031-12036