Introduction to DiGeorge syndrome

DiGeorge syndrome is a rare congenital disease that affects an infant's immune system and that is due to a large deletion from chromosome 22. The syndrome is marked by the absence or underdevelopment of the thymus and parathyroid glands. It is named for the pediatrician who first described it in 1965.

Normally the thymus gland is located below the thyroid gland in the neck and front of the chest and is the primary gland of the primary gland of the lymphatic system, which is necessary for normal functioning of the immune system. The parathyroid glands, located on the sides of the thyroid gland, are responsible for the maintenance of normal levels of calcium in the blood. In children with DiGeorge syndrome, the thymus and parathyroid glands are missing or undeveloped. The symptoms of this disorder vary, depending on the extent of missing thymus and parathyroid tissue. The primary problem for children who survive with DiGeorge syndrome is repeated infections due to a defective immune system.

DiGeorge syndrome is sometimes described as a "CATCH 22" disorder, so named because of their characteristics- cardiac defects (C), abnormal facial features (A), thymus underdevelopment (T), cleft palate (C), and hypocalcemia due to hypothyroidism (H)- all resulting from deletion of portions of chromosome 22. Specific facial features associated with DiGeorge syndrome include low-set ears, wide-set eyes, a small jaw, and a short groove in the upper lip.

DiGeorge syndrome is also called congenital thymic hypoplasia, or third and fourth pharyngeal pouch syndrome because the congenital abnormalities occur in areas known as the third and fourth pharyngeal pouches, which later develop into the thymus and parathyroid glands.