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A developmental defect of derivatives of the third and fourth pharyngeal pouches, almost always associated with agenesis or hypoplasia of the thymus and parathyroid gland, characteristic facies with downslanting palpebral fissures and ocular and nasal anomalies, hypocalcemia, cardiovascular anomalies, immunodeficiency, and other variable abnormalities. Patients who survive infancy are usually mentally retarded. DiGeorge syndrome is considered by some researchers as a developmental field defect consisting of several casually distinct disorders, rather than a distinct syndromic entity. Conditions associated with the development of DiGeorge syndrome include diabetic embryopathy, fetal alcohol syndrome, and Zellweger syndrome. Major features of this syndrome have been designated by the Newcastle Upon Tyne Group CATCH 22 (Cardiac, Abnormal facies, Thymic hypoplasia, Cleft palate, and Hypocalcemia), the number 22 indicating deletion of the long arm of chromosome 22 (22q11).
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Branchial arch defects with craniofacial abnormalities, hearing loss, short stature, and learning difficulty.
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Deletion of the long arm of chromosome 22 with variable dysmorphic features consisting of a round face, almond-shaped palpebral fissures, bulbous nose, malformed ears, hypotonia, short stature, mental retardation, and other anomalies. Deletion of the proximal long arm of chromosome 22 (22q11) has been associated with familial DiGeorge and velocardiofacial syndromes and terminal deletion was found in Goldenhar syndrome. Abnormalities of chromosome 22 are also suspected of being involved in the etiology of neoplastic diseases.
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