Nonrandom inactivation of the Y-bearing X chromosome in a 46, XX individual: Evidence for the etiology of 46, XX true hermaphroditism

Patricia Y. Fechner, C. Rosenberg, G. Stetten, C. B. Cargile, P. L. Pearson, K. D. Smith, C. J. Migeon, G. D. Berkovitz

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We previously reported a subject with 46, XX true hermaphroditism who had a 46, X, del(X) karyotype and Y- chromosomal sequences in genomic DNA. We hypothesized that the Y-chromosomal sequences were translocated to the deleted X chromosome and that the incomplete testis determination of this individual was the result of inactivation of the translocated X chromosome. In situ hybridization studies demonstrated that the Y-chromosomal sequences were located on the distal portion of the short arm of the deleted X chromosome. Investigation of the replication of the X chromosome, using a modified R-banding technique and localization of Y-chromosomal sequences by in situ hybridization, showed that the translocated X chromosome was late replicating in all 100 EBV-transformed lymphoblasts that were examined. By- contrast, when cells from a subject with 46, XX maleness were studied, the translocated X chromosome was late replicating in only 21 of 47 cells. As the late-replicating X chromosome is presumed to be the inactive X chromosome, selection of cells in which the Y-bearing X chromosome has been inactivated may play a role in the incomplete testis determination in subjects with “Y-positive” 46, XX true hermaphroditism.

Original languageEnglish (US)
Pages (from-to)22-261
Number of pages240
JournalCytogenetic and Genome Research
Issue number1
StatePublished - Jan 1 1994


ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Genetics(clinical)

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