A case of a parthenogenetic 46,XX/46,XY chimera presenting ambiguous genitalia

Rie Kawamura, Takema Kato, Shunsuke Miyai, Fumihiko Suzuki, Yuki Naru, Maki Kato, Keiko Tanaka, Miwako Nagasaka, Makiko Tsutsumi, Hidehito Inagaki, Tomoaki Ioroi, Makiko Yoshida, Tomoya Nao, Laura K. Conlin, Kazumoto Iijima, Hiroki Kurahashi, Mariko Taniguchi-Ikeda

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Sex-chromosome discordant chimerism (XX/XY chimerism) is a rare chromosomal disorder in humans. We report a boy with ambiguous genitalia and hypospadias, showing 46,XY[26]/46,XX[4] in peripheral blood cells. To clarify the mechanism of how this chimerism took place, we carried out whole-genome genotyping using a SNP array and microsatellite analysis. The B-allele frequency of the SNP array showed a mixture of three and five allele combinations, which excluded mosaicism but not chimerism, and suggested the fusion of two embryos or a shared parental haplotype between the two parental cells. All microsatellite markers showed a single maternal allele. From these results, we concluded that this XX/XY chimera is composed of two different paternal alleles and a single duplicated maternal genome. This XX/XY chimera likely arose from a diploid maternal cell that was formed via endoduplication of the maternal genome just before fertilization, being fertilized with both X and Y sperm.

Original languageEnglish
Pages (from-to)705-709
Number of pages5
JournalJournal of Human Genetics
Issue number8
Publication statusPublished - 01-08-2020

All Science Journal Classification (ASJC) codes

  • Genetics
  • Genetics(clinical)


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