Multiple active X chromosomes in myelofibrosis with myeloid metaplasia.
A woman with myelofibrosis and myeloid metaplasia had a karyotype of 47,X,del(X)(q22),+del(X)(q22) in unstimulated peripheral blood and bone marrow aspirate cultures. The normal X chromosome was late replicating, and the two deleted X chromosomes always replicated early and synchronously. The karyotype from phytohemagglutin-stimulated peripheral blood cultures was uniformly 46,XX. Structurally abnormal X chromosomes are exceedingly rare in myeloproliferative disease. The abnormal karyotype very likely reflects monoclonal proliferation of an abnormal myeloid cell line. The X chromosome inactivation process, which acts upon embryonic somatic cells of all mammals, apparently does not react to postembryonic nondisjunction of the active X chromosome.
D001853:Bone Marrow / Q000473:pathology; D002869:Chromosome Aberrations / Q000235:genetics*; D002871:Chromosome Banding; D025063:Chromosome Disorders; D002904:Chromosomes, Human, 21-22 and Y; D005260:Female; D006801:Humans; D007621:Karyotyping; D008875:Middle Aged; D055728:Primary Myelofibrosis / Q000235:genetics* / Q000473:pathology; D012730:Sex Chromosomes; D014960:X Chromosome