title: Skewed X chromosome inactivation may be not associated with premature ovarian failure.
abstract: BACKGROUND
  In view of the controversies about the skewed X chromosome inactivation (XCI) and premature ovarian failure (POF) association, a meta-analysis of the published data was performed to evaluate the relationship between XCI skewing and POF.
  
  
  METHODS
  We searched for all published articles indexed in MEDLINE (1950 approximately 2009) and CNKI (1994 approximately 2009). Any case-control or cohort study that tested the association between skewed XCI and POF was included and data were extracted independently by two reviewers. We performed this meta-analysis involving 325 cases and 403 controls with Review Manager 4.2 software.
  
  
  RESULTS
  Four eligible studies were selected for meta-analysis. It suggested that there was no significant difference between the incidence of skewed XCI (XCI >or=70% skewing) in POF cases comparing to healthy controls, odds ratio (OR) = 1.13 [95% confidence interval (CI): 0.84 approximately 1.53, P = 0.42]. The link between extremely skewed XCI (XCI >or=90% skewing) and POF was also analysed, and no significant difference was found, either, OR = 1.46 (95% CI: 0.79 approximately 2.69, P = 0.22).
  
  
  CONCLUSIONS
  Skewed XCI had no association with POF. However, more case-control and cohort studies are needed in the future.
authors.affiliation: Department of Obstetrics and Gynecology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Danhua
authors.initials: D
authors.lastname: Pu
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.forename: Jiayin
authors.initials: J
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D041321:Chromosomes, Human, X / Q000235:genetics*; D005260:Female; D006801:Humans; D008875:Middle Aged; D016649:Primary Ovarian Insufficiency / Q000235:genetics*; D049951:X Chromosome Inactivation / Q000235:genetics*; D055815:Young Adult