母体血浆中游离胎儿DNA在无创性产前诊断中的应用研究

Research of Fetal DNA in Maternal Plasma in Prenatal Diagnosis

目的 建立一种从孕妇血浆中检测胎儿DNA的无创性产前诊断新方法。方法 对30例孕7～41周妇女血浆游离DNA进行聚合酶链反应,特异性扩增的胎儿基因为Y染色体上的DYZ1位点,扩增片段的大小为149bp。30例孕妇血浆均经过酚氯仿法提取DNA作为模板,进行聚合酶链反应。结果 20例妊娠男性胎儿孕妇中有17例出现DYZ1基因扩增条带,检出率为85.0％。10例妊娠女性胎儿孕妇中未出现阳性扩增条带,无假阳性结果。本研究中早、中、晚孕期性别符合率分别为80％,80％,90％,总符合率为85.0％。结论 用酚氯仿法提取血浆中的DNA,可以提高模板的浓度和纯度,可改善PCR条件,提高结果的准确性。

Objective To establish a new method for detection of fetal DNA in maternal plasma for non-invasive prenatal diagnosis. Methods A Y-chromosome-specific repeat sequence-DYZ1 gene of fetal DNA was amplified by PCR from 30 maternal plasma (7 ~ 41 weeks). A149bp specific fragment was obtained. The DNA template was obtained by Thenol-chloroform methods from maternal plasma. Results The fragment was identified in 17 of 20 male bearing pregnant women plasma.The diagnostic accordance rate was 85% ,none of the 10 female bearing pregnant women had positive results. Among the 30 pregnant women, the diagnostic coincidence rate was 80% at early pregnant stage,80% at medium pregnant stage,and 90% at late stage.The final accuracy of 85% was attained in all cases. Conclusion By Thenol-chloroform methods we increase the concentration and purity of the DNA template, and make the diagnosis more accurately. As the technique of uninvasive prenatal diagnosis, it can be applied to clinical work.