22q11.2 deletion syndrome

22q11.2 deletion syndrome is a genetic disorder caused by loss of a segment of chromosome 22q11.2. Its effects vary widely and can involve the heart, immune system, palate, development, and mental health.

22q11.2: A chromosome 22 region on its long arm, near band q11.2, that contains genes commonly deleted in this syndrome. The syndrome is defined by loss of genetic material from this chromosomal region.
Chromosomal microarray: A laboratory method that detects gains and losses of DNA across the genome. It can identify the chromosome 22 deletion that establishes the diagnosis.
Angelo DiGeorge: An American pediatric endocrinologist who described a syndrome involving thymic and parathyroid underdevelopment and congenital heart disease. His observations anticipated a subset of features now associated with the deletion.
Hypocalcemia: An abnormally low concentration of calcium in the blood. Parathyroid underdevelopment can cause low calcium, sometimes emerging after infancy.
22q11.2 duplication syndrome: A genetic condition caused by an extra copy of a segment of chromosome 22q11.2. It involves increased rather than decreased dosage of material from the same region.
TBX1: A transcription-factor gene in 22q11.2 that contributes to development of the pharyngeal apparatus and related structures. Its dosage is linked to several characteristic developmental effects of the deletion.
Fluorescence in situ hybridization: A laboratory technique that uses fluorescent DNA probes to detect specific chromosome sequences. Targeted probes can detect common 22q11.2 deletions, though not every atypical deletion.
Robert Shprintzen: An American speech-language pathologist and researcher who characterized velocardiofacial syndrome. His clinical description overlaps substantially with 22q11.2 deletion syndrome.
Cleft palate: A congenital opening in the roof of the mouth caused by incomplete fusion during development. Palatal abnormalities can affect feeding, speech, and middle-ear health in the syndrome.
CHARGE syndrome: A genetic condition, usually caused by CHD7 variants, involving characteristic congenital anomalies. Some features overlap, but its usual genetic cause differs from the 22q11.2 deletion.

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