We present 2 cases of double mosaic aneuploidy harboring 2 or more different aneuploid cell lines, but no line with a normal chromosome constitution. One of these cases presented mosaicism of sex chromosome aneuploid cell lines (47,XXX/45,X) along with another line containing an autosomal trisomy (47,XX,+8), while the other case showed mosaicism of 2 different autosomal trisomy cell lines (47,XY,+5 and 47,XY,+8). To elucidate the mechanisms underlying these mosaicisms, we conducted molecular cytogenetic analyses. Genotyping data from the SNP microarray indicated that 2 sequential meiotic or early postzygotic segregation errors likely had occurred followed by natural selection. These cases suggest that frequent segregation errors and selection events in the meiotic and early postzygotic stages lead to this condition.

中文翻译：

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两例双镶嵌非整倍体起源分析

我们提出了 2 例双镶嵌非整倍体，其中包含 2 个或更多不同的非整倍体细胞系，但没有具有正常染色体构成的细胞系。其中一个病例表现出性染色体非整倍体细胞系 (47,XXX/45,X) 的嵌合现象以及另一条含有常染色体三体性 (47,XX,+8) 的细胞系，而另一个病例表现出 2 个不同的常染色体三体细胞的嵌合线（47,XY,+5 和 47,XY,+8）。为了阐明这些镶嵌现象背后的机制，我们进行了分子细胞遗传学分析。来自 SNP 微阵列的基因分型数据表明，在自然选择之后可能发生了 2 个连续的减数分裂或早期合子后分离错误。这些案例表明减数分裂和合子后早期阶段频繁的分离错误和选择事件导致了这种情况。