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Prader–Willi syndrome phenocopy due to duplication of Xq21.1–q21.31, with array CGH of the critical region
Author(s) -
Gabbett MT,
Peters GB,
Carmichael JM,
Darmanian AP,
Collins FA
Publication year - 2008
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1111/j.1399-0004.2007.00960.x
Subject(s) - gene duplication , biology , phenocopy , comparative genomic hybridization , genetics , breakpoint , tandem exon duplication , x chromosome , karyotype , non allelic homologous recombination , phenotype , copy number variation , chromosome , gene , genome , genetic recombination , recombination
We report on a 4‐year‐old male with an interstitial tandem duplication of Xq21.1–q21.31 who presented with clinical features of Prader–Willi syndrome (PWS). The duplication was maternally inherited. Abnormalities of the X chromosome have previously been reported in association with a PWS phenotype, but to date, specific duplications of Xq21.1–q21.31 have not. We refined the chromosomal breakpoints seen on initial G‐banded karyotyping in our case with comparative genomic hybridization by microarray (array CGH). The duplication was between 11.1 and 14.4 Mb in length and overlaps with three loci to which mental retardation with PWS‐like features have been previously mapped, showing the utility of array CGH in helping to identify candidate genes. We conclude that duplication of chromosomal region Xq21.1–q21.31 potentially results in a PWS‐like phenotype. Reviewing the literature on similar duplications, we further conclude that distal Xq duplications can result in features typically seen in infants with PWS, while proximal duplications can result in features typically seen in older children and adults with PWS. Duplications of chromosome Xq should be considered in the differential diagnosis of PWS, especially in males.