DiGeorge Anomaly
DiGeorge anomaly is a congenital immunodeficiency disorder in which the thymus gland is absent or underdeveloped at birth.
Usually, DiGeorge anomaly is due to a chromosomal abnormality but is not usually hereditary. The fetus does not develop normally, and abnormalities of the heart, parathyroid gland, face, and thymus gland often result. The thymus gland is necessary for the normal development of T lymphocytes. Consequently, people with this disorder have a low number of T lymphocytes, limiting their ability to fight many infections. Infections begin soon after birth and recur often. However, the degree to which the immune system is affected varies considerably.
Typically, children with DiGeorge anomaly also have symptoms that are unrelated to immunodeficiency, such as congenital heart disease and unusual facial features, with low-set ears, a small jawbone that recedes, and wide-set eyes. They also are born without parathyroid glands, which help regulate the calcium levels in the blood. The resulting low calcium levels lead to muscle spasms (tetany).
For children who have some T lymphocytes, the immune system may function adequately without treatment. Infections that develop are treated promptly. For children who have very few or no T lymphocytes, transplantation of stem cells or thymus tissue can cure the immunodeficiency.
A low calcium level is treated with calcium supplements to prevent muscle spasms. Sometimes the heart disease is worse than the immunodeficiency, and surgery to prevent severe heart failure or death may be needed. The prognosis usually depends on the severity of the heart disease.
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