全染色体涂抹探针在女性罗伯逊易位携带者植入前遗传学诊断中的临床应用

目的应用全染色体涂抹探针（whole chromosome painting probe，WCP）对女性罗伯逊易位携带者进行卵母细胞第一极体的植入前遗传学诊断（preimplantation genetic diagnosis，PGD）。方法应用全染色体涂抹探针进行第一极体荧光原位杂交，对4例女方罗伯逊易位携带者进行了4个周期的PGD。患者染色体核型均为45，XX，der（13；14），（q10；q10）。所有周期取卵后6h内通过活检取出第一极体，采用WCP探针进行荧光原位杂交，受精后第3天选择染色体组成正常或平衡的胚胎进行宫腔内移植。结果4个周期共获卵61个，其中54个成熟可进行活检，活检成功率92．6％（50／54），固定成功率90．O％（45／50）。40个获得明确诊断，总体诊断率为74．1％（40／54）。卵胞浆内单精子注射后受精率64．8％（35／54），优质胚胎率为65．7％（23／35）。获得2例临床妊娠。其中1例于孕9周胚胎停止发育，绒毛染色体分析核型为45，X；另1例产前诊断证实核型为46，XX。2006年6月足月分娩一正常活女婴。结论全染色体涂抹探针可准确区分正常、平衡以及异常卵子，从而可有效应用于女性染色体易位携带者的PGD。

The clinical application of whole chromosome painting probes in preimplantation genetic diagnosis for translocation carriers

Objective To make preimplantation genetic diagnosis (PGD) for female translocation carriers by analyzing first polar bodies (1PBs) with whole chromosome painting probe (WCP). Methods WCP was used in fluorescence in situ hybridization (FISH) analysis of 1PBs for four female Robertsonian carriers presented for PGD with 45 XX, der(13;14)(q10;q10) karyotype. All the patients underwent ovarian stimulation and during 6 h after oocyte retrieval 1PBs were biopsied and WCP were used in FISH. On day 3 after fertilization embryos diagnosed as normal or balanced were transferred. Results A total of 61 oocytes were collected in 4 PGD cycles. Of the 54 matured oocytes, 50 were biopsied and 45 were fixed successfully. Results were obtained in 40 1PBs. Overall, 74.1%(40/54)oocytes were diagnosed. The fertilization rate and good embryo rate were 64.8%(35/54)and 65.7%(23/35)respectively. Two clinical pregnancies were obtained. One patient delivered a normal female baby with karyotype 46,XX in June 2006. For another patient, the fetus spontaneously aborted at 9th week of pregnancy with karyotype of 45, X confirmed by amniotic villus diagnosis. Conclusion WCP can differentiate normal, balanced and unbalanced oocytes accurately and can be used as an efficient PGD method for female carriers of translocation.