The 22q11 Deletion Syndromes (DiGeorge, Shprintzen, Takao)


The contiguous gene deletion syndromes comprise a group of disorders defined by characteristic dysmorphisms or behaviors in association with a submicroscopic chromosome deletion that is detected using fluorescence in situ hybridization (FISH) or microarray technologies. In each case, the deleted segment contains multiple genes that play varying roles in producing a particular phenotype. Angelman, Beckwith-Wiedemann, Wolf-Hirschhorn (4p-), Prader-Willi, and 22q11 deletion syndromes are among the best delineated contiguous gene deletion syndromes.

22q11 Deletion Syndrome (the long arm of chromosome 22 at band 11), which occurs in approximately 1 in 4,000 births, is the most common of the contiguous gene deletion syndromes. 22q11 deletion syndrome should be suspected in any child who has a conotruncal heart defect (eg, tetralogy of Fallot, double-outlet right ventricle, truncus arteriosus), especially if accompanied by developmental delay, dysmorphic features, or recurrent upper respiratory tract infections. Testing for the condition involves sending blood for FISH (it must be specified that the region of interest is 22q11) or for microarray analysis, assuming the array covers the 22q11 region. DiGeorge, Takao and Shprintzen syndromes are all manifestations of the submicroscopic deletions in the 22q11 region.

DiGeorge syndrome (Mnemonic: CATCH 22)

Takao syndrome

Shprintzen (velocardiofacial):

Isolated outflow tract defects of the heart also occur

Mnemonic: CATCH 22

CHLA board review course 2005
Baraitser and Winter, 1996. Color Atlas of Congenital Malformation Syndromes