Course : MOC Part IV: 22q11.2 Deletion Syndrome
Assessment and Management of Patients with 22q11.2 deletion syndrome
The 22q11.2 deletion syndrome is one of the most common chromosome abnormalities, with an estimated prevalence of 1 in 4000 individuals. While a large number of congenital anomalies and health issues have been described in association with this condition, it is unlikely that any given affected person will have every feature. The most common findings include:
- Congenital heart defects, particularly conotruncal heart defects
- Abnormalities of the palate (cleft palate, velopharyngeal insufficiency)
- Hypocalcemia, either present at birth or during periods of physical stress
- Immunological deficiencies
- Learning disabilities
- Characteristic facial features
The condition is due most commonly to a recurrent deletion of approximately 2.54-Mb on chromosome 22q11.2 which includes TBX1. The deletion can be detected through various methods, including FISH analysis, multiplex ligation-dependent probe amplification (MLPA), or chromosomal microarray. Individuals who have known* atypical deletions or who have duplication of this region should not be included in this module.
*FISH analysis does not determine the size of the deletion; individuals who have a positive FISH for the 22q11.2 deletion may be included in this module. In rare instances, these patients may actually have deletions that are smaller or larger than the typical deletion, which may be unrecognized in the absence of further studies to accurately determine the extent of the deletion.
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