22q11.2 microdeletion (the cause of 22q deletion syndrome)

22q11.2 microdeletion, an absence of a small piece of chromosome 22,1  happens in about 1 in 1000 pregnancies.2,3  It is the second most common genetic cause of heart defects and developmental delay after Down syndrome,4 and is the underlying cause of DiGeorge and velocardiofacial syndromes (VCFS). 22q11.2 microdeletion is not reliably detected by routine prenatal screening or karyotype.4 Unlike trisomies, maternal age is not a risk factor for the microdeletion2 and family history cannot reliably predict its occurrence as more than 90% of affected individuals have no family history.

For more detailed information about 22q11.2 microdeletion including pregnancy management, health care guidelines, advocacy and support for families:




Learn more about the Harmony prenatal test for 22q11.2 microdeletion.


1. Rauch et al. Am J Med Genet A. 2006 Oct 1;140(19):2063-74

2. McDonald-McGinn et al. Genet Med. 2001 Jan-Feb;3(1):23-9

3. McDonald-McGinn et al. Genet Couns. 1999;10(1):11-24

4. Bassett et al. J Pediatr. 2011 Aug;159(2):332-9