The DiGeorge syndrome is an example of a selective T-cell deficiency caused by the failure of development of the third and fourth pharyngeal pouches.
These pouches give rise to the following structures:
- aortic arch
- portions of the lips and ears
Consequently, DiGeorge syndrome may present with as immune deficiency state - usually T cells, but sometimes B cells, and also aberrant calcium metabolism, congential heart disease and abnormal facies.