Generating and modifying DiGeorge syndrome-like phenotypes in model organisms: is there a common genetic pathway?

Most DiGeorge syndrome (DGS) patients have a similar chromosomal 22q11.2 deletion (del22q11) but show great clinical variability, suggesting the presence of genetic modifiers. We review recent mouse studies describing DGS-like phenotypes associated with mutations in genes not. included in del22q11. It is reasonable to predict that mutations at these loci in humans might cause DGS in patients without del22q11, or could modify the del22q11 phenotype. We discuss how these loci might interact with the leading DGS candidate gene, the transcription factor Tbx1.