Mapping of the distal boundary of the X-inactivation center in a rearranged X chromosome from a female expressing XIST.


Journal Article

A female patient with primary amenorrhea, immature secondary sexual characteristics, and tall stature was found to have a normal X chromosome and a rearranged X [rea(X)] chromosome that resembled an 'isochromosome' Xp, but retained the proximal portion of Xq. The rea(X) was interpreted as rec(X)dup p,inv(X)(p11.4q13). Replication studies demonstrated that the rea(X) was always the late-replicating and, therefore, presumably inactive X chromosome, which must contain the X-inactivation center. Consistent with this interpretation, fluorescence in situ hybridization demonstrated that the rea(X) retained the XIST gene, and reverse transcription polymerase chain reaction analysis showed that XIST was expressed in the patient's cells. By fluorescence in situ hybridization with previously mapped probes, the breakpoint of the rea(X) was located within an approximately 500-kb region located approximately 200 to 700 kb distal to the XIST locus. This is the closest breakpoint distal to XIST in an inactivated X chromosome and, therefore, defines a new distal boundary for the X-inactivation center in humans.

Full Text

Cited Authors

  • Leppig, KA; Brown, CJ; Bressler, SL; Gustashaw, K; Pagon, RA; Willard, HF; Disteche, CM

Published Date

  • July 1993

Published In

Volume / Issue

  • 2 / 7

Start / End Page

  • 883 - 887

PubMed ID

  • 8364571

Pubmed Central ID

  • 8364571

Electronic International Standard Serial Number (EISSN)

  • 1460-2083

International Standard Serial Number (ISSN)

  • 0964-6906

Digital Object Identifier (DOI)

  • 10.1093/hmg/2.7.883


  • eng