The features of this syndrome vary widely, even among members of the same family, and affect many parts of the body. Characteristic signs and symptoms may include birth defects such as congenital heart disease, defects in the palate, most commonly related to neuromuscular problems with closure (velo-pharyngeal insufficiency), learning disabilities, mild differences in facial features, and recurrent infections. Infections are common in children due to problems with the immune system's T-cell mediated response that in some patients is due to an absent or hypoplastic thymus. 22q11.2 deletion syndrome may be first spotted when an affected newborn has heart defects or convulsions from hypocalcemia due to malfunctioning parathyroid glands and low levels of parathyroid hormone (parathormone). Affected individuals may also have any other kind of birth defect including kidney abnormalities and significant feeding difficulties as babies. Autoimmune disorders such as hypothyroidism and hypoparathyroidism or thrombocytopenia (low platelet levels), and psychiatric illnesses are common late-occurring features. Microdeletions in chromosomal region 22q11.2 are associated with a 20 to 30-fold increased risk of schizophrenia.
Studies provide various rates of 22q11.2 deletion syndrome in schizophrenia, ranging from 0.5 to 2% and averaging about 1%, compared with the overall estimated 0.025% risk of the 22q11.2 deletion syndrome in the general population. Medical students may use the mnemonic CATCH-22 to describe DiGeorge's syndrome, with the 22 to remind one the chromosomal abmormality is found on the 22 chromosome:
Cardiac Abnormality (especially Tetralogy of Fallot)
Abnormal facies
Thymic aplasia
Cleft palate
Hypocalcemia
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