Mosaic or chimera? Revisiting an old hypothesis about the cause of the 46,XX/46,XY hermaphrodite

J Pediatr. 2002 Jun;140(6):732-5. doi: 10.1067/mpd.2002.124321.


Objectives: A cell lineage in a hermaphrodite infant showing a 46,XX/46,XY karyotype was analyzed to determine the genetic contribution from both parents and identify the underlying mechanism.

Study design: Genotype analysis was performed by using 57 microsatellite markers, 39 distributed on 9 autosomes and 18 on the X-chromosome. Two X- and Y-specific markers were analyzed to confirm the presence and percentages of cells containing a Y-chromosome.

Results: The proband revealed a single maternal and paternal allele for all of the informative autosomal and X-chromosome markers. Analysis of the X- and Y-specific markers confirmed that approximately 20% of the patient's peripheral blood cells contained the Y chromosome.

Conclusions: The data suggest that the patient's hermaphroditism was the result of a mosaic embryo and not a chimera. The most likely mechanism involved 2 separate nondisjunction events, resulting in the loss of 47,XXY cells during early embryonic development.

Publication types

  • Case Reports

MeSH terms

  • Chimera*
  • Disorders of Sex Development / genetics*
  • Fertilization / genetics*
  • Genotype
  • Humans
  • Infant, Newborn
  • Male
  • Microsatellite Repeats*
  • Mosaicism*