title: Extremely skewed X-chromosome inactivation patterns in women with recurrent spontaneous abortion.
abstract: BACKGROUND
  The role of extremely skewed X-chromosome inactivation (XCI) has been questioned in the pathogenesis of recurrent spontaneous abortion (RSA) but the results obtained were conflicting.
  
  
  OBJECTIVE
  We therefore investigated the XCI patterns in peripheral blood DNA obtained from 80 patients who had RSA and 160 age-matched controls.
  
  
  METHODS
  Pregnancy history, age, karyotype, and disease information was collected from all subjects. The methylation status of a highly polymorphic cytosine-adenine-guanine repeat in the androgen-receptor (AR) gene was determined by use of methylation-sensitive restriction enzyme HpaII and polymerase chain reaction.
  
  
  RESULTS
  Skewed XCI (> 85% skewing) was observed in 13 of the 62 patients informative for the AR polymorphism (20.9%), and eight of the 124 informative controls (6.4%) (P = 0.0069; chi2 test). More importantly, extremely skewed XCI, defined as > 90% inactivation of one allele, was present in 11 (17.7%) patients, and in only two controls (P = 0.0002; chi2 test).
  
  
  CONCLUSIONS
  These results support the interpretation that disturbances in XCI mosaicism may be involved in the pathogenesis of RSA.
authors.affiliation: Department of Molecular Biology and Genetics, Faculty of Science, Bilkent University, Ankara, Turkey.
authors.forename: Sevgi
authors.initials: S
authors.lastname: Bagislar
authors.forename: Isik
authors.initials: I
authors.lastname: Ustuner
authors.forename: Bora
authors.initials: B
authors.lastname: Cengiz
authors.forename: Feride
authors.initials: F
authors.lastname: Soylemez
authors.forename: Cemaliye Boylu
authors.initials: CB
authors.lastname: Akyerli
authors.forename: Serdar
authors.initials: S
authors.lastname: Ceylaner
authors.forename: Gulay
authors.initials: G
authors.lastname: Ceylaner
authors.forename: Aynur
authors.initials: A
authors.lastname: Acar
authors.forename: Tayfun
authors.initials: T
authors.lastname: Ozcelik
mesh_terms: D000026:Abortion, Habitual / Q000235:genetics*; D000483:Alleles; D004247:DNA / Q000097:blood; D019175:DNA Methylation; D005260:Female; D006801:Humans; D009030:Mosaicism; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011944:Receptors, Androgen / Q000235:genetics*; D049951:X Chromosome Inactivation
chemical_list: D011944:Receptors, Androgen; D004247:DNA