目的:建立适合中国广东地区人群特点的唐氏综合征快速产前诊断技术,并评价其临床应用价值.方法:选取21号染色体上杂合度较高的3个短串联重复序列(STR,D21S1411、D21S1412、D21S1270)作为遗传标记,采用多重荧光定量聚合酶链反应(QF-PCR)扩增技术,对广东地区106例无亲缘关系的正常人外周血DNA进行分析,计算这3个STR位标的多态性信息含量(PIC);用该方法对25例唐氏综合征患儿外周血和10例正常孕妇羊水的DNA进行检测,并与染色体核型分析结果进行对照分析.结果:21号染色体上的3个STR(D21S1411、D21S1412、D21S1270)的PIC分别为0.913、0.835、0.856,确立了QF-PCR产前诊断唐氏综合征的方法.对25例唐氏综合征患儿外周血和10例孕妇羊水同时进行QF-PCR检测与染色体核型分析,两种方法均检测到27例唐氏综合征,结果吻合.结论:本研究所选STR位标在中国广东人群中呈现较高的遗传多态性,符合Hardy-Weinberg平衡定律;所构建的QF-PCR技术产前诊断唐氏综合征具有准确、快速、高效等特点,有较高的临床使用价值.%Objective: To establish the technique of quantitative fluorescence multiplex polymerase chain reaction ( QF - PCR)and evaluate its clinical application in prenatal diagnosis of Down syndrome in Guangdong Province.Methods: Three high polymorphic short tandem repeat (STR) (D21S1411 、D21S1412、D21S1270) markers in chromosomes of 21 were selected,in which aneuploidies occurred more often than others.A total of 106 peripheral blood DNA samples of normal Guangdong hans without genetic relationship were analysed with QF - PCR amplification and three STR - bit target polymorphism information contents (PICs) were calculated.A total of 25 peripheral blood samples of Down Syndrome patients and 10 amniotic fluid samples of normal pregnant women were tested with the technique established.All the samples were performed the routine chromosome karyotype analysis simultaneously.Results: The PICs of D21S1411, D21S1412 and D21S1270 were 0.913,0.835 and 0.856, respectively.A QF - PCR method for prenatal diagnosis of Down syndrome was established.The test results of 25 blooed samples and 10 amniotic fluid samples using this technique were coincident with those of chromosome karyotype analysis.Twenty-seven cases of Down syndrome were detected.Conclusion: The STR markers selected are all highly polymorphic and in accordance with Hardy - Weinberg principle.And the application of QF - PCR in prenatal diagnosis of Down Syndrome has higher clinical values and better market prospects for its high sensitivity and efficient.
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