[Importance of aneuploidy screening in preimplantation genetic diagnosis for the couples of chromosome translocation carriers]

Abstract

Objective: To determine the importance of aneuploidy screening in preimplantation genetic diagnosis for the couples of chromosome translocation carriers.

Methods: To perform 11 prenatal genetic diagnosis (PGD) cycles for 7 couples of chromosome translocation carriers from January 2006 to March 2009 in the Reproductive Medical Center, First Affiliated Hospital of Zhengzhou University. To re-analyze the well-fixed, non-multinuclear and non-debris nuclei using the probes of LSI 13, 18, 21, CEPX, CEPY to detect the aneuploidy rate which come from the PGD cycles of the couples of chromosome translocation carriers. The euploid embryo was defined as two fluorescence in situ hybridization (FISH) signals of LSI 13, 18, 21 respectively and two signals of CEPX, or one signal of CEPX and one signal of CEPY. The other abnormal signals were defined as aneuploid embryo.

Results: (1) A total of 130 nuclei from 11 PGD cycles got the integrated re-FISH signals. Nine hundred and thirty-seven FISH signals were analyzed, including 304 signals from 38 euploid nuclei and the others from 92 aneuploid nuclei. (2) The number of the aneuploid nuclei from grade I, II and III embryo was 20 (22%), 36 (39%), and 36 (39%). The number of the euploid nuclei from grade I, II and III embryo was 13(34%), 17 (45%), and 8 (21%). There was no significant difference of aneuploidy rate between the embryos form different grades (P > 0.05). However, the rate of aneuploid nucleus from good quality embryos (grade I + grade II) was 60% (59/92). (3) The euploidy rate was 71.4% (30/42) from balanced embryos, while 9.1% (8/88) from unbalanced embryos. There was significant difference between them (χ² = 53.4, P < 0.05). The rate of aneuploidy from balanced embryos was lower than those from unbalanced embryos (P < 0.05).

Conclusions: Since higher rate of aneuploidy was detected in embryos of the couples of chromosome translocation carriers. It is advisable to recommend the FISH re-analysis for aneuploidy screening to preimplantation genetic diagnosis for the couples of chromosome translocation carriers.