[Preliminary analysis of chromosome mosaicism in preimplantation embryos].

OBJECTIVE

Using fluorescence in situ hybridization to analyze chromosome mosaicism in human preimplantation embryos and access the influence of mosaicism on in vitro fertilization-embryo transfer (IVF-ET) and preimplantation genetic diagnosis.

METHODS

Normal fertilized embryos, which were not suitable for embryo transfer and cryopreservation, and male embryos in preimplantation gender diagnosis were analyzed by fluorescence in situ hybridization.

RESULTS

Two hundred and ninety three nucleuses were found among 38 embryos. The hybridization rate was 96.2%. Twelve embryos (31.6%) were normal. Twenty-eight embryos (73.7%) were diploid embryos, which included normal diploid embryos and embryos with diploid moscaicism. In addition, 19 (50.0%) embryos were considered to be chromosomal mosaics due to diploid mosaicism and abnormal mosaicsm. The frequency of mosaicism increased from 18.2% in < or = 4 cell-stage embryos to 68.4% and 50.0% in 5-8 cell-stage and > or = 9 cell-stage embryos respectively.

CONCLUSION

The frequency of Mosaicism increases with successive cleavage divisions. Moscaicism may be one of the important factors affecting the success rates in IVF-ET. Identification of sex by analysis of a single cleavage cell is accurate; however, it would be better to biopsy 2 cells to reduce errors in preimplantation genetic diagnosis of single gene diseases.