[Analysis of chromosome mosaicism in preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization].
OBJECTIVE
To investigate the mechanism and factors affecting mosaicism in human preimplantation embryos by using 2 sequential rounds of fluorescence in situ hybridization(FISH).


METHODS
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.


RESULTS
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%).


CONCLUSIONS
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.
Ren
Xiu-lian
XL
Reproductive Medical Center, the First Affiliated Hospital, SUN Yat-sen University, Guangzhou, Guangdong, 510080 PR China.
Xu
Yan-wen
YW
Zhou
Can-quan
CQ
Zhuang
Guang-lun
GL
D000782:Aneuploidy; D001755:Blastocyst; D002877:Chromosomes, Human; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D009030:Mosaicism / Q000139:chemically induced / Q000196:embryology*; D019836:Preimplantation Diagnosis