T-cell deficiency characterized by severe infections, absent thymus, abnormal parathyroid and heart, abnormal ears, congenital defects of the great vessels, and micrognathia. Male predominance is 2 to 1. Death occurs within 1st months of life. Cause is defect on chromosome 22q11. When receiving transfusions, patients require irradiated blood. There are normal levels of plasma cells and circulating antibodies. Causes include deletions on chromosome 22 (22q11.2q11.2) and chromosome 10, fetal alcohol syndrome, and retinoic acid embryopathy. Also with obsessive behavior and schizophreniform disorder.