immune disorders
DiGeorge Syndrome
Introduction
DiGeorge syndrome is a congenital immunodeficiency disorder in which the thymus gland is absent or underdeveloped at birth, causing problems with T cells , a type of white blood cell that helps identify and destroy foreign or abnormal cells. Other birth defects also are present. Children with DiGeorge syndrome are born with several abnormalities, including heart defects, underdeveloped or absent parathyroid glands, an underdeveloped or absent thymus gland, and characteristic facial features. T-cell problems cause recurrent infections. Doctors do blood tests, take a chest x-ray to look for and evaluate the thymus gland, and usually do echocardiography to check for heart defects. If children have no T cells, transplantation of thymus tissue or stem cells is necessary to preserve life. (See also Overview of Immunodeficiency Disorders .) DiGeorge syndrome is a Primary immunodeficiency . Usually, it is due to a The fetus does not develop normally, and abnormalities often occur in the following: Children are often born with a Overview of Heart Defects (a heart defect present at birth). Parathyroid gland:Children are usually born with underdeveloped or no parathyroid glands (which help regulate calcium levels in the blood). As a result, calcium levels are low, leading to muscle spasms (tetany). Spasms usually start within 48 hours after birth. Face:Typically, children have characteristic facial features, with low-set ears, a small jawbone that recedes, and wide-set eyes. They may have a split in the roof of the mouth (cleft palate). The thymus gland is necessary for the normal development of T cells . Because this gland is missing or underdeveloped, the number of T cells is low, limiting their ability to fight many infections. Infections begin soon after birth and recur often. However, how well T cells function varies considerably. Also, T cells may spontaneously start functioning better. The prognosis usually depends on the severity of the heart disorder. 