{Reference Type}: Case Reports
{Title}: A case of a parthenogenetic 46,XX/46,XY chimera presenting ambiguous genitalia.
{Author}: Kawamura R;Kato T;Miyai S;Suzuki F;Naru Y;Kato M;Tanaka K;Nagasaka M;Tsutsumi M;Inagaki H;Ioroi T;Yoshida M;Nao T;Conlin LK;Iijima K;Kurahashi H;Taniguchi-Ikeda M;
{Journal}: J Hum Genet
{Volume}: 65
{Issue}: 8
{Year}: Aug 2020
{Factor}: 3.755
{DOI}: 10.1038/s10038-020-0748-4
{Abstract}: 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.