The 22q11 deletion syndrome is one of the most common multiple anomaly syndromes in humans and has historically been referred to as velocardiofacial syndrome, DiGeorge sequence, conotruncal anomalies face syndrome, CATCH 22, and Sedlackova syndrome, all different names describing the same disorder. This syndrome has an expansive phenotype with more than 180 clinical features that can involve every organ and system. The syndrome is caused by a microdeletion of chromosome 22 at the q11.2 band. The syndrome has a prevalence of approximately 1 in 3,000 to 6,000 live births in the United States. About 6% to 10% of cases are inherited, while the remainder are due to de novo mutations.

The majority of patients have a constellation of abnormalities resulting from an embryogenic disruption in the formation of the third and fourth aortic arches. The common clinical features are hypocalcemia, immunodeficiency, dysmorphic facial features, palatal and velopharyngeal dysfunction, renal anomalies, congenital heart disease (CHD), and intellectual disability. The DiGeorge variant is characterized by thymic and parathyroid aplasia or hypoplasia, cardiovascular defects, and dysmorphic facies. Depending on the extent of the thymic hypoplasia, clinical manifestations can range from frequent upper respiratory tract infections to severe immunodeficiency that can only be corrected with T-cell-replete hematopoietic stem cell transplantation (HSCT) or thymus transplantation.

References

• Bartik LE, Hughes SS, Tracy M, et al. 22q11.2 duplications: expanding the clinical presentation. Am J Med Genet A. 2022;188:779-787.
• Campbell IM, Sheppard SE, Crowley TB, et al. What is new with 22q? An update from the 22q and You Center at the Children's Hospital of Philadelphia. Am J Med Genet A. 2018;176:2058-2069.
• Cirillo A, Lioncino M, Maratea A, et al. Clinical manifestations of 22q11.2 deletion syndrome. Heart Fail Clin. 2022;18:155-164.
• Goldmuntz E. 22q11.2 deletion syndrome and congenital heart disease. Am J Med Genet C Semin Med Genet. 2020;184:64-72.