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 for selected products have been updated. These updates ensure a consistent presentation of all gaps larger than 10 kb including adjustments to markers, genes, and related elements. This update does not affect the device characteristics or product composition. Please refer to the list to find out which products now include updated probe maps.

Probe map details are based on UCSC Genome Browser GRCh37/hg19, with map components not to scale.

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