Chromosomal constitution of embryos derived from tripronuclear zygotes studied by fluorescence in situ hybridization using probes for chromosomes 4, 13, 18, 21, X, and Y

초록

This study was designed to assess the chromosomal constitution and segregation patterns of cleaving embryos derived from tripronuclear zygotes. Thirty-two embryos obtained from 19 conventional IVF patients were analyzed by fluorescence in situ hybridization (FISH) using probes for chromosomes 4, 13, 18, 21, X, and Y. Sixteen embryos (50.0%) exhibited uniform, non-mosaic patterns. These embryos showed pure triploid (n = 7), pure diploid ( n = 7), or pure haploid ( n = 2). The remaining 16 embryos showed mosaic patterns; 1 was triploid-diploid mosaics, 9 were diploid-haploid, and 4 were haploid only. Autosomal aneuploidy occurred in 2 embryos showing a triploid complement. The sex chromosomal constituent XXX: XXY: XYY was 3: 4: 2 in embryos showing a pure triploid complement ( including 2 embryos with aneuploidy). This ratio was not significantly different from the expected 1: 2: 1 ( p = 0.96). Pure triploid was found in 41.7% of 2-cell embryos, but no triploid complement was found in 3-cell embryos. The present study also supports the diandric origin of tripronuclear zygotes in the conventional IVF, and, to our knowledge, is the first study to use simultaneous six-color FISH for chromosomes 4, 13, 18, 21, X, and Y in human embryos. However, no additive information was obtained about chromosome 4. Copyright (C) 2005 S. Karger AG, Basel.

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