In recent years, through a variety of mouse mutants that carry multigene and single gene mutations, we have learned that mutation in a single gene, Tbx1, is responsible for most of the congenital defects seen in the mouse models and in patients.
Deletions within 22q11 have been associated with a wide variety of birth defects embraced by the acronym CATCH22 and including the DiGeorge syndrome, Shprintzen syndrome (velocardiofacial syndrome) and congenital heart disease.