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An atypical 0.73 MB microduplication of 22q11.21 and a novel SALL4 missense mutation associated with thumb agenesis and radioulnar synostosis
Author(s) -
Diehl Adam,
Mu Weiyi,
Batista Denise,
GunayAygun Meral
Publication year - 2015
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.37066
Subject(s) - missense mutation , genetics , gene duplication , digeorge syndrome , biology , dysostosis , agenesis , chromosomal inversion , chromosomal deletion , mutation , medicine , chromosome , karyotype , gene , congenital disease
We describe a 0.73 Mb duplication of chromosome 22q11.21 between LCR‐B and LCR‐D and a missense mutation in a conserved C2H2 zinc finger domain of SALL4 in a cognitively normal patient with multiple skeletal anomalies including radioulnar synostosis, thumb aplasia, butterfly vertebrae, rib abnormalities, and hypoplasia of the humeral and femoral epiphyses. 22q11.21 is a common site for microdeletions and their reciprocal microduplications as a result of non‐allelic homologous recombination between its multiple low copy repeat regions (LCR). DiGeorge /Velocardiofacial syndrome (DG/VCFS) is classically caused by a 3 Mb deletion between LCR‐A and LCR‐D or a 1.5 Mb deletion between LCR‐A and LCR‐B. The reciprocal syndrome to DG/VCFS is the recently described 22q11.2 microduplication, which usually presents with the typical 3 Mb or 1.5 Mb duplication. Numerous atypical deletions and duplications have been reported between other LCRs. Typically, SALL4 ‐related Duane‐radial ray syndrome is caused by deletions or nonsense mutations; the only missense SALL4 mutation described prior was thought to result in gain of function and produced cranial midline defects. The skeletal anomalies presented in this report have not been previously described in association with 22q11.2 microduplication nor SALL4 mutations. © 2015 Wiley Periodicals, Inc.