Analysis of chromosome mosaicism in preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization / 中华医学遗传学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the mechanism and factors affecting mosaicism in human preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization(FISH).</p><p><b>METHODS</b>Totally 51 normal fertilized embryos, which were not suitable for embryo transfer and cryopreservation, were analyzed on day 3 after fertilization by using two sequential rounds of FISH. Chromosomes 13, 16, 18, 21, 22, X and Y were analyzed.</p><p><b>RESULTS</b>Among 51 embryos, 16 (31.4%) were mosaic, 12 (23.5%) were chaotic, and the remaining were either normal (27.5%) or non-mosaic abnormal (17.6%). The incidence of mosaic embryos was related to embryo developmental stage, for the incidence of mosaicism increased from 12.5% in embryos <or= 4 cell stage to 40.0% in 5-8 cell stage embryos. The aneuploidy rate for the patients over 35 years of age was significantly higher than that of the patients under 35 years (57.1% vs 23.3%).</p><p><b>CONCLUSION</b>Mosaicism is common in human preimplantaion embryos, which may be one of the important factors affecting the success rates in IVF-ET. Most of the chromosomal abnormalities can be identified by two sequential rounds of FISH.</p>