Ring chromosome X in a child with manifestations of Kabuki syndrome.

TitleRing chromosome X in a child with manifestations of Kabuki syndrome.
Publication TypeJournal Article
Year of Publication1997
AuthorsMcGinniss MJ, Brown DH, Burke LW, Mascarello JT, Jones MC
JournalAmerican journal of medical genetics
Volume70
Issue1
Pagination37-42
Date Published1997 May 2
Abstract

A female patient with the karyotypei 45,X/46, X, r(X)(p11.2 q13) and severe developmental delay, prominent fingertip pads, long palpebral fissuresi, short stature, and history of hypotonia had a phenotypei reminiscent of Kabuki syndrome. We hypothesized that overexpression of X chromosomei-derived sequences might be associated with the Kabuki-like phenotype observed. The nature and parental origin of this small-ring X were ascertained using a combination of genotyping with microsatellite markers and quantitative Southern blotting. PCR-based genotyping demonstrated heterozygosityi at X-linked loci SBMA (Xq11-q12) and DXS227 (Xq13.1). Hemizygosity was observed at several loci: DMD STR-49 (Xp21.2), DXS1003 (Xp11.23), DXS988 (Xp11.21), DXS101 (Xq21.3), FMR-1 (Xq27.3), and DXYS64 (Xq28). This ring X chromosome is paternally derived since only maternal alleles are inherited at three informative microsatellite loci. Results of FISH and RT-PCR experiments indicate that the XIST locusi is missing in the ring X chromosome and not expressed. These data indicated a large deletion of the X chromosome consistent with a small-ring X chromosome with approximate breakpoints near p11.2 and q13. These results are comparable to the observation of others where an atypically severe phenotype has been associated with the presence of an r(X), or small mar(X).

Alternate JournalAm. J. Med. Genet.
Citation Key9129739