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Severe hypohidrotic ectodermal dysplasia in a girl caused by a de novo 9;X insertion that includes XIST and disrupts the EDA gene
Author(s) -
Ørstavik Karen Helene,
Knudsen Gun Peggy S.,
Nordgarden Hilde,
Ormerod Eli,
Strømme Petter,
Lazarou Lazarous P.,
Rosser Lyndon G.,
Prescott Trine,
Houge Gunnar
Publication year - 2007
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.31797
Subject(s) - hypohidrotic ectodermal dysplasia , xist , locus (genetics) , x inactivation , biology , genetics , x chromosome , breakpoint , ectodermal dysplasia , gene , chromosome , microbiology and biotechnology
X‐linked hypohidrotic ectodermal dysplasia (XLHED) is caused by mutations in the EDA gene. A girl with severe hypohidrotic ectodermal dysplasia and normal mental development had completely skewed X chromosome inactivation with only the paternal X active in peripheral blood cells. Routine chromosome analysis and sequencing of the EDA gene were normal. However, whole chromosome painting revealed a 9;X insertion. FISH analyses with BAC probes towards the EDA gene and the more distal region containing the XIST locus showed that an X chromosome fragment of at least 4 Mb containing XIST was inserted into 9p13 in conjunction with a de novo pericentric inversion of chromosome 9. The proximal breakpoint was within the EDA gene and the distal breakpoint was distal to the XIST locus. Both parents had normal chromosomes, and the mother had random X inactivation in peripheral blood cells. Because XIST was lacking on the X chromosome with the disrupted EDA gene, the normal X chromosome was inactivated resulting in severe XLHED. © 2007 Wiley‐Liss, Inc.