22q11.2 deletion syndrome → σύνδρομο έλλειψης 22q11.2, σύνδρομο DiGeorge

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22q11.2 deletion syndromeσύνδρομο διαγραφής του 22q11.2, σύνδρομο DiGeorge;

22q11.2 deletion syndrome, which has several presentations including DiGeorge syndrome (DGS), DiGeorge anomaly, velo-cardio-facial syndrome, Shprintzen syndrome, conotruncal anomaly face syndrome, Strong syndrome, congenital thymic aplasia, and thymic hypoplasia is a syndrome caused by the deletion of a small piece of chromosome 22. The deletion occurs near the middle of the chromosome at a location designated q11.2 i.e., on the long arm of one of the pair of chromosomes 22, on region 1, band 1 , sub-band 2. It has a prevalence estimated at 1:4000. The syndrome was described in 1968 by the pediatric endocrinologist Angelo DiGeorge.

« Last Edit: 08 Feb, 2012, 10:09:52 by Thomas »
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deletion → εξάλειψη, απάλειψη, έλλειψη

This classic example of isolated T cell deficiency results from maldevelopment of thymic epithelial elements derived from the third and fourth pharyngeal pouches. The gene defect has been mapped to chromosomal position 22q11 in most patients with the diGeorge syndrome, and to 10p in others. Defective development of organs dependent on cells of embryonic neural crest origin includes congenital cardiac defects, particularly those involving the great vessels; hypocalcemic tetany, due to failure of parathyroid development; and absence of a normal thymus. Facial abnormalities may include abnormal ears, shortened philtrum, micrognathia, and hypertelorism. Serum immunoglobulin concentrations are frequently normal, but antibody responses, particularly of IgG and IgA isotypes, are usually impaired. T cell levels are reduced, whereas B cell levels are normal. Affected individuals often have a small, histologically normal thymus located near the base of the tongue or in the neck, allowing most patients to develop functional T cells in numbers that may or may not be adequate for host defense.
(Εσωτερική Παθολογία Harrison)

« Last Edit: 08 Feb, 2012, 10:11:00 by Thomas »


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