22q11.2 deletion syndrome
The 22q11.2 deletion syndrome, also known as the DiGeorge syndrome or velocardiofacial syndrome, is a syndrome where a small portion of the chromosome 22 is lost and results in a variable but a recognisable pattern of physical and behavioural features.
The estimated incidence is at ~ 1 in 4000 live pregnancies 4.
CATCH 22 is the mnemonic to remember the chromosome and all the abnormalities.
- cleft lip +/- palate
- congenital heart disease (particularly conotruncal anomalies): often a major part of this syndrome
- characteristic facies
- elongated face
- long philtrum
- facial asymmetry
- prominent nose
- hypernasal speech
- learning disabilities
- decreased immunity
- malformation of 3rd and 4th pharyngeal pouches that result in the defective development of the parathyroid and thymus which can, in turn, lead to
There is a near-universal association with a deletion within chromosome 22q11.2. The majority of cases have de novo mutations. 22q11 deletions are associated with some types of conotruncal cardiac defects as well as conotruncal anomaly face syndrome 5.
History and etymology
First described in 1968 by Angelo DiGeorge.
- 1. Wilson DI, Burn J, Scambler P et-al. DiGeorge syndrome: part of CATCH 22. J. Med. Genet. 1993;30 (10): 852-6. doi:10.1136/jmg.30.10.852 - Free text at pubmed - Pubmed citation
- 2. Lipson AH, Yuille D, Angel M et-al. Velocardiofacial (Shprintzen) syndrome: an important syndrome for the dysmorphologist to recognise. J. Med. Genet. 1991;28 (9): 596-604. J. Med. Genet. (link) - Free text at pubmed - Pubmed citation
- 3. Alikaşifoğlu M, Malkoç N, Ceviz N et-al. Microdeletion of 22q11 (CATCH 22) in children with conotruncal heart defect and extracardiac malformations. Turk. J. Pediatr. 2000;42 (3): 215-8. Pubmed citation
- 4. Oskarsdóttir S, Vujic M, Fasth A. Incidence and prevalence of the 22q11 deletion syndrome: a population-based study in Western Sweden. Arch. Dis. Child. 2004;89 (2): 148-51. Free text at pubmed - Pubmed citation
- 5. Driscoll DA. Genetic basis of DiGeorge and velocardiofacial syndromes. Curr. Opin. Pediatr. 1995;6 (6): 702-6. Pubmed citation