双色共变性荧光原位杂交产前诊断胎儿唐氏综合征

目的 探讨双色共变性荧光原位杂交用于非侵入性产前诊断胎儿唐氏综合征的可行性。方法 对11例孕妇外周血中的胎儿有核红细胞进行抗血型糖蛋白磁珠直接标记，再经磁激活细胞分选法富集，以Y和21号染色体专一探针对分离的胎儿有核红细胞行双色共变性荧光原位杂交，预测胎儿21号染色体倍性和性别，并用羊水染色体核型分析结果，验证预测准确性。结果 11例胎儿21号染色体倍性均正常，与羊水染色体核型分析结果相符。其中5例为男性胎儿，男性胎儿有核红细胞数量为9－65个，平均为25个，男性胎儿有核红细胞纯度为1．4％－18．8％；6例为女性胎儿，孕妇外周血中未见男性胎儿有核红细胞；性别预测结果与羊水染色体型分析结果一致。结论 双色共变性荧光原位杂交用于分析胎儿21号染色体倍性及性别，诊断胎儿唐氏综合征准确、可靠。

Non-invasive prenatal diagnosis of fetal Down syndome by dual-color fluorescence in situ hybridization with co-denaturation

OBJECTIVE: To explore the possibility of non-invasive prenatal diagnosis of Down syndrome by dual color fluorescence in situ hybridization with co-denaturation. METHODS: Fetal nucleated red blood cells labeled by anti-glycophorin a monoclonal immunomagnetic microbeads were enriched from maternal peripheral blood by magnetic activated cell sorting. The ploidy of chromosome 21 and sex of fetuses were determined using two-color fluorescence in situ hybridization with 21 and Y chromosome probes denatured by codenaturation. The accuracy of prediction was verified according to the karyotype of fetuses by analysis of amniotic cells. RESULTS: The ploidy of chromosome 21 of fetuses from 11 pregnant women was predicted normal. The results were correctly identified by the fetal karyotypes. 5 pregnant women were predicted carrying male fetuses. The number and mean number of male fetal nucleated red blood cells were 9-65 and 25 per 2 ml, respectively. The purity of male fetal erythrocytes enriched from maternal peripheral blood was 1.4%-18.8%; 6 pregnant women were predicted carrying female fetuses, and no male fetal nucleated red blood cell was found. The results of sex prediction were consistent with the kayotypes of fetuses by analysis of amniotic cells. CONCLUSION: It is possible to predict the ploidy of chromosome 21 and the sex of fetuses when fetal nucleated erythrocytes enriched by direct immunomagnetic labeling followed by magnetic activated cell sorting are analyzed using two-color fluorescence in situ hybridization with Y and 21 chromosome probes through codenaturation.