Open Access
Molecular mechanisms and diagnosis of chromosome 22q11.2 rearrangements
Author(s) -
Emanuel Beverly S.
Publication year - 2008
Publication title -
developmental disabilities research reviews
Language(s) - English
Resource type - Journals
eISSN - 1940-5529
pISSN - 1940-5510
DOI - 10.1002/ddrr.3
Subject(s) - non allelic homologous recombination , breakpoint , digeorge syndrome , genetics , biology , chromosomal translocation , chromosome 22 , gene duplication , chromosome , gene , recombination , genetic recombination
Abstract Several recurrent, constitutional genomic disorders are present on chromosome 22q. These include the translocations and deletions associated with DiGeorge and velocardiofacial syndrome and the translocations that give rise to the recurrent t(11;22) supernumerary der(22) syndrome (Emanuel syndrome). The rearrangement breakpoints on 22q cluster around the chromosome‐specific segmental duplications of proximal 22q11, which are involved in the etiology of these disorders. While the deletions are the result of nonallelic homologous recombination (NAHR) between low copy repeats or segmental duplications within 22q11, the t(11;22) is the result of rearrangement between palindromic AT‐rich repeats on 11q and 22q. Here we describe the mechanisms responsible for these recurrent rearrangements, discuss the recurrent deletion endpoints that are the result of NAHR between chromosome 22q specific low copy repeats as well as present current diagnostic approaches to deletion detection. © 2008 Wiley‐Liss, Inc. Dev Disabil Res Rev 2008;14:11–18.