title: Molecular detection of altered X-inactivation patterns in the diagnosis of genetic disease.
abstract: It is widely assumed that when a female carrier of a genetic disorder exhibits clinical signs of the disorder it is due to chance non-random X-inactivation in particular tissues. Recently molecular methods have become available for the analysis of X-chromosome inactivation status. These are based either on the methylation patterns of DNA from the active and inactive chromosomes or on the rescue of active X chromosomes in somatic cell hybrids. As a consequence of the molecular studies, it has become obvious that there are some special cases of non-random X-inactivation patterns. These include females carrying X-linked immunodeficiencies and, sometimes, one of a pair of identical female twins.
authors.affiliation: Molecular Genetics Unit, Institute of Child Health, London, UK.
authors.forename: S
authors.initials: S
authors.lastname: Malcolm
mesh_terms: D004200:Diseases in Twins / Q000235:genetics; D004303:Dosage Compensation, Genetic; D005260:Female; D030342:Genetic Diseases, Inborn / Q000175:diagnosis* / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D008745:Methylation; D014430:Twins, Monozygotic; D014960:X Chromosome