PDF(Pubmed)
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.
摘要：
性染色体不一致嵌合体（XX/XY嵌合体）是人类罕见的染色体疾病。我们报道了一个生殖器模糊和尿道下裂的男孩，外周血细胞中显示46，XY[26]/46，XX[4]。为了阐明这种嵌合体是如何发生的机制，我们使用SNP阵列和微卫星分析进行了全基因组基因分型.SNP阵列的B等位基因频率显示三个和五个等位基因组合的混合物，排除了镶嵌性，但不排除嵌合体，并建议两个胚胎融合或两个亲本细胞之间共享的亲本单倍型。所有微卫星标记显示单个母体等位基因。从这些结果来看,我们得出结论，该XX/XY嵌合体由两个不同的父系等位基因和一个重复的母系基因组组成。这种XX/XY嵌合体可能是由受精前通过母体基因组内复制形成的二倍体母体细胞产生的，用X和Y精子受精。
