title: X chromosome-inactivation patterns of 1,005 phenotypically unaffected females.
abstract: X-chromosome inactivation is widely believed to be random in early female development and to result in a mosaic distribution of cells, approximately half with the paternally derived X chromosome inactive and half with the maternally derived X chromosome inactive. Significant departures from such a random pattern are hallmarks of a variety of clinical states, including being carriers for severe X-linked diseases or X-chromosome cytogenetic abnormalities. To evaluate the significance of skewed patterns of X inactivation, we examined patterns of X inactivation in a population of >1,000 phenotypically unaffected females. The data demonstrate that only a very small proportion of unaffected females show significantly skewed inactivation, especially during the neonatal period. By comparison with this data set, the degree of skewed inactivation in a given individual can now be quantified and evaluated for its potential clinical significance.
authors.affiliation: Department of Genetics, Case Western Reserve Univeristy, Cleveland, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Amos-Landgraf
authors.forename: Amy
authors.initials: A
authors.lastname: Cottle
authors.forename: Robert M
authors.initials: RM
authors.lastname: Plenge
authors.forename: Mike
authors.initials: M
authors.lastname: Friez
authors.forename: Charles E
authors.initials: CE
authors.lastname: Schwartz
authors.forename: John
authors.initials: J
authors.lastname: Longshore
authors.forename: Huntington F
authors.initials: HF
authors.lastname: Willard
mesh_terms: D000328:Adult; D002452:Cell Count; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D010641:Phenotype; D013234:Stem Cells / Q000166:cytology; D049951:X Chromosome Inactivation / Q000235:genetics*