The deletion occurs near the middle of the chromosome at a location designated q The features of this syndrome vary widely, even among affected members of the same family. People with 22q In affected individuals, the muscles that form the roof of the mouth palate may not close completely, even though the tissue covering them does, resulting in a condition called submucosal cleft palate. The abnormal palate is often highly arched and there may be a split in the soft flap of tissue that hangs from the back of the mouth bifid uvula. Submucosal cleft palate can also interfere with normal speech by causing air to come out of the nose during speech, leading to nasal-sounding speech.
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DiGeorge Syndrome is a primary immunodeficiency disease caused by abnormal migration and development of certain cells and tissues during fetal development. As part of the developmental defect, the thymus gland may be affected and T-lymphocyte production may be impaired, resulting in low T-lymphocyte numbers and frequent infections. DiGeorge Syndrome DGS is a primary immunodeficiency, often but not always, characterized by cellular T-cell deficiency, characteristic facies, congenital heart disease and hypocalcemia.
DGS is caused by abnormal formation of certain tissues during fetal development. During fetal development, various tissues and organs often arise from a single group of embryonic cells.
Although the tissues and organs that ultimately develop from this group of embryonic cells may appear to be unrelated in the fully formed child, they do have a similar origin. Thus another name for this syndrome is the 22q Other names include velocardiofacial syndrome and conotruncal anomaly face syndrome. While the genetic defect is the same in the majority of patients with DGS, they all do not present in the same way. For example, some patients with DGS have severe cardiac anomalies; some have none at all.
Some have major learning disabilities; others have none. This is called phenotypic variability. There is wide phenotypic variability in patients with DGS. Unusual facial appearance - Features may include an underdeveloped chin, eyes with heavy eyelids, ears that are rotated back and small upper portions of their ear lobes.
These facial characteristics vary greatly from person to person and may not be prominent in many patients. Heart defects - These include a variety of heart or cardiac defects. The defects usually involve the aorta and the part of the heart from which the aorta develops. In some patients, heart defects may be very mild or absent.
Thymus gland abnormalities - The thymus is crucial in the development of the cellular T-cell immune system. It is normally located in the upper area of the front of the chest behind the breastbone. The thymus begins its development high in the neck during the first three months of fetal development.
As the thymus matures and gets bigger, it drops down into the chest to its ultimate location under the breastbone and in front of the heart. Patients with a small thymus produce fewer T-lymphocytes than those with a normally sized thymus. T-lymphocytes are essential for protection against infections.
Some T-lymphocytes, the cytotoxic T-lymphocytes, directly kill viruses. T-lymphocytes also help B-lymphocytes to develop into antibody producing plasma cells.
Patients with DGS may have poor T-cell production compared to their peers, and as a result, have an increased susceptibility to viral, fungal and bacterial infections.
As with the other defects in DGS, the T-lymphocyte defect varies from patient to patient. In a very small number of patients with DGS the thymus is completely absent, so the number of T-cells is severely low. These patients require prompt medical attention since they are severely immunocompromised.
The majority of patients with DGS have less severe or mild deficiencies. Autoimmunity - Patients with DGS develop autoimmune disease at a rate that is higher than in the general population. Autoimmune disease occurs when the immune system inappropriately attacks its own body. The most common autoimmune diseases in DGS are idiopathic thrombocytopenia purpura antibodies against platelets , autoimmune hemolytic anemia antibodies against red blood cells , autoimmune arthritis, and autoimmune disease of the thyroid gland.
Parathyroid gland abnormalities - These glands may be underdeveloped in patients with DGS, causing hypoparathyroidism. People with DGS may have trouble maintaining normal levels of calcium, and this may cause seizures convulsions. In some cases, the parathyroid abnormality is not present at all, relatively mild or only a problem during times of stress such as severe illness or surgery.
The parathyroid defect often becomes less severe over time. Miscellaneous clinical features - Patients with DGS may have a variety of other developmental abnormalities including cleft palate, poor function of the palate, delayed acquisition of speech and difficulty in feeding and swallowing.
In addition, some patients have learning disabilities, behavioral problems, psychiatric disorders and hyperactivity. For example schizophrenia occurs at a higher rate in patients with DGS compared to the rate in the general population. The diagnosis of DGS is made on the basis of signs and symptoms that are present at birth, or develop soon after birth, along with confirmatory genetic testing.
Some infants may have facial features that are characteristic of DGS. Affected infants may also show signs of low blood calcium levels as a result of hypoparathyroidism. Affected infants may also show signs and symptoms of a heart defect.
These may include a heart murmur that is detected on a routine physical exam. Affected infants may also develop infection because of their low T-lymphocyte levels. In some children, all of the classical features are present and the diagnosis of DGS is made very early. In other people, all of the different organs and tissues may not be affected, and the organs and tissues that are involved may be impaired to different degrees so that the presentation is more subtle and the diagnosis is not made until later on in life when a speech delay, feeding problems or autoimmune disease are noted.
In the past, the diagnosis of DGS was usually made when all the characteristic findings described above were present without obtaining a confirmatory genetic test.
Unfortunately, this caused many mild cases to be missed. In recent years, the genetic test has been more widely used. But once the diagnosis has been made, genetic counseling is critically important and testing should be offered to parents and other family members. DGS is the most common microdeletion syndrome. The rate of occurrence is estimated at approximately 1 in 4, people.
For patients who do not have the 22q11 microdeletion, a DGS diagnosis can still be made on the basis of the characteristic combination of clinical features and by excluding a diagnosis of other syndromes. Therapy for DGS is aimed at correcting the defects in the affected organs or tissues. Therefore, therapy depends on the nature of the different defects and their severity. In general, patients with DGS have the same response rates to therapies as do the general population. Treatment of the low calcium and hypoparathyroidism may involve calcium supplementation and replacement of the missing parathyroid hormone.
A heart or cardiac defect may require medications or corrective surgery to improve the function of the heart.
Surgery can be performed before any immune defects are corrected. If there is a problem with the T-cells, precautions must be taken as with other children with congenital T-cell immunodeficiencies. These include irradiating all blood products to prevent graft vs. The need for therapy of the T-lymphocyte defect varies.
Most people with DGS have normal T-lymphocyte function and do not require therapy for immunodeficiency. Other children initially have mild defects in T-lymphocyte function that improve, as they grow older. In these cases the small amount of thymus tissue present provides adequate T-lymphocyte function. Immunologic care for patients with DGS includes monitoring the overall immune system including the numbers and function of T-lymphocytes.
Patients who have initially been deemed immunocompetent but then develop frequent, severe or unusual infections should have their immune system reevaluated. This is a serious, potentially fatal, condition that is similar to Severe Combined Immune Deficiency.
In this situation, T-cells must be reconstituted for the infant to survive. This can be achieved with a thymus transplant available only on a research basis or by stem cell transplantation.
In some patients with DGS, the T-lymphocyte defect is significant enough to cause the B-lymphocytes to fail to make sufficient antibodies. This occurs because antibodies are produced by B-lymphocytes under the direction of a specific subset of T-lymphocytes. Immunoglobulin replacement therapy is sometimes required. The outlook for people with DGS depends on the function of each affected organ system. The severity of heart disease is usually the most important determining factor.
Early diagnosis is important and optimal management of patients with DGS requires a multidisciplinary approach including an immunologist as part of the team of specialists. This page contains general medical information which cannot be applied safely to any individual case. Medical knowledge and practice can change rapidly. Therefore, this page should not be used as a substitute for professional medical advice.
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Sign up for action alerts. Get peer support. Designed by BackOffice Thinking. Skip to main content. DiGeorge Syndrome. You are here Home. Definition of DiGeorge Syndrome DiGeorge Syndrome DGS is a primary immunodeficiency, often but not always, characterized by cellular T-cell deficiency, characteristic facies, congenital heart disease and hypocalcemia.
Patients with DGS may have any or all of the following: Unusual facial appearance - Features may include an underdeveloped chin, eyes with heavy eyelids, ears that are rotated back and small upper portions of their ear lobes.
Diagnosis of DiGeorge Syndrome The diagnosis of DGS is made on the basis of signs and symptoms that are present at birth, or develop soon after birth, along with confirmatory genetic testing. Management of DiGeorge Syndrome Immunologic care for patients with DGS includes monitoring the overall immune system including the numbers and function of T-lymphocytes. Description of DiGeorge from the Online Mendelian Chromosome 22q Related Videos.
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From Wikimedia Commons, the free media repository. T cell deficiency disease that is the result of a large deletion of chromosome 22 which includes the DGS gene needed for development of the thymus and related glands with subsequent lack of T-cell production. Angelo DiGeorge. Q Library of Congress authority ID: sh Subcategories This category has the following 2 subcategories, out of 2 total. Media in category "DiGeorge syndrome" The following 4 files are in this category, out of 4 total.
DiGeorge Syndrome is a primary immunodeficiency disease caused by abnormal migration and development of certain cells and tissues during fetal development. As part of the developmental defect, the thymus gland may be affected and T-lymphocyte production may be impaired, resulting in low T-lymphocyte numbers and frequent infections. DiGeorge Syndrome DGS is a primary immunodeficiency, often but not always, characterized by cellular T-cell deficiency, characteristic facies, congenital heart disease and hypocalcemia. DGS is caused by abnormal formation of certain tissues during fetal development. During fetal development, various tissues and organs often arise from a single group of embryonic cells. Although the tissues and organs that ultimately develop from this group of embryonic cells may appear to be unrelated in the fully formed child, they do have a similar origin.
DiGeorge syndrome, more accurately known by a broader term — 22q This deletion results in the poor development of several body systems. The term 22q Medical problems commonly associated with 22q The number and severity of symptoms associated with 22q