胚胎染色体非整倍体筛查用于平衡易位携带者植入前的遗传学诊断

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

目的探讨胚胎染色体非整倍体筛查在平衡易位携带者植入前遗传学诊断（PGD）中的价值。方法2006年1月至2009年3月，郑州大学第一附属医院生殖医学中心对7对平衡易位携带者夫妇进行了11个PGD周期，从中选择固定良好、无多核、无核碎片的细胞核，应用荧光原位杂交（nSH）分析技术筛查13、18、21、X、Y染色体的非整倍体情况。如13、18、21号染色体有2个杂交信号，2个X性染色体杂交信号或1个X染色体杂交信号和1个Y染色体杂交信号者，则诊断为整倍体胚胎；异常杂交信号的胚胎则诊断为非整倍体胚胎。结果（1）11个平衡易位的PGD周期中，选出杂交信号完整的130个细胞核进行分析，FISH共分析了937个荧光杂交信号，其中整倍体细胞核38个，共有304个杂交信号；其余92个为非整倍体细胞核。（2）在92个非整倍体细胞核中，Ⅰ、Ⅱ及Ⅲ级胚胎的比例分别为20个（22％）、36个（39％）及36个（39％）；38个整倍体细胞核中，Ⅰ、Ⅱ及Ⅲ级胚胎的比例分别为13个（34％）、17个（45％）及8个（21％），两者的Ⅰ、Ⅱ及Ⅲ级胚胎数分别比较，差异均无统计学意义（P〉0．05）。虽然染色体整倍体率在不同级别胚胎中的分布比较，差异均无统计学意义（P〉0．05），但优质胚胎（Ⅰ级＋Ⅱ级）中非整倍体率仍为60％（56／92）。（3）平衡胚胎来源的卵裂球细胞核整倍体率（71．4％，30／42）明显高于非平衡胚胎来源的卵裂球细胞核整倍体率（9．1％，8／88），两者比较，差异有统计学意义（P〈0．05）。平衡胚胎来源的卯裂球细胞核非整倍体率（包括三体、单体、复杂非整倍体、单倍体、多倍体）明显低于非平衡胚胎来源的卵裂球细胞核非整倍体率（P〈0．05）。结论平衡易位携带者的胚胎中有较高的非整倍体率，因此，胚胎非整倍体筛查在平衡易位携带者的PGD中有重要价值和临床意义。

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 disgnosis （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 tolal of 130 nuclei from 11 PGD cycles got the integrated re-FISH signals. Nine hundred and thirty-seven FISH signals were analysized, 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 （ X^2 = 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.