title: Replication and inactivation of a dicentric X formed by telomeric fusion.
abstract: A woman complaining of secondary amenorrhea and infertility was found to have, in addition to a normal X chromosome, a long compound chromosome that consisted of two X chromosomes attached by telomeric fusion of the short arms without any apparent loss of genetic material, 46,X,dic(X)(pter), hereafter referred to as t(X;X). The t(X;X) chromosome was late replicating; the inactivation pattern was analyzed. It formed Barr bodies that were larger than normal, of which the majority were bipartite. Analysis of the X-chromatin masses supports our hypotheses that there is a region next to the centromere on the short arm of the inactive X chromosome that remains active and that there is an inactivation center located on Xq, a short distance from the centromere, around which the X chromatin condenses.
mesh_terms: D000328:Adult; D001345:Autoradiography; D002503:Centromere; D005260:Female; D006570:Heterochromatin; D006801:Humans; D012728:Sex Chromatin; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D014960:X Chromosome
chemical_list: D006570:Heterochromatin