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Variable immune deficiency related to deletion size in chromosome 22q11.2 deletion syndrome
Author(s) -
Crowley Blaine,
Ruffner Melanie,
McDonald McGinn Donna M.,
Sullivan Kathleen E.
Publication year - 2018
Publication title -
american journal of medical genetics part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.064
H-Index - 112
eISSN - 1552-4833
pISSN - 1552-4825
DOI - 10.1002/ajmg.a.38597
Subject(s) - deletion syndrome , immune system , biology , digeorge syndrome , breakpoint , t cell , immunodeficiency , gene duplication , chromosome , genetics , immunology , phenotype , gene
The clinical features of 22q11.2 deletion syndrome include virtually every organ of the body. This review will focus on the immune system and the differences related to deletion breakpoints. A hypoplastic thymus was one of the first features described in this syndrome and low T cell counts, as a consequence of thymic hypoplasia, are the most commonly described immunologic feature. These are most prominently seen in early childhood and can be associated with increased persistence of viruses. Later in life, evidence of T cell exhaustion may be seen and secondary deficiencies of antibody function have been described. The relationship of the immunodeficiency to the deletion breakpoints has been understudied due to the infrequent analysis of people carrying smaller deletions. This manuscript will review the immune deficiency in 22q11.2 deletion syndrome and describe differences in the T cell counts related to the deletion breakpoints. Distal, non‐ TBX1 inclusive deletions, were found to be associated with better T cell counts. Another new finding is the relative preservation of T cell counts in those patients with a 22q11.2 duplication.