母体血循环中胎儿游离DNA的检测

目的寻找一种无创性产前基因检测孕妇血浆中胎儿游离DNA的新方法。方法提取32名健康孕妇血浆标本中胎儿游离DNA，经套式聚合酶链反应（PCR）扩增其性别决定基因（sex-determiningregion Y，SRY），并引入内参照基因序列ArrLl；并采用16个短串联重复序列（shorttandemrepeat，STR）多态性位点的多重荧光PCR方法对血浆标本中DNA进行STR等位基因扩增。同时，检测孕妇及其丈夫的外周血白细胞DNA，进行基因扫描及对照分析。结果经SRY-PCR检测发现，17名妊娠男胎孕妇血浆中均出现基因扩增带，其余15名妊娠女胎孕妇中有2名出现假阳性，性别总符合率为94％（30／32）。经STR-PCR检测发现，均从孕妇血浆中检测出父源性胎儿DNA的存在。结论应用孕妇血浆中胎儿DNA作产前诊断准确性较高，是一种无创性产前基因诊断方法，具有广泛的临床应用前景。

Detection of circulating fetal DNA in maternal plasma for non-invasive prenatal diagnosis

Objective To explore the application of fetal DNA in maternal plasma for non-invasive prenatal diagnosis.Methods The DNA template was extracted by QIAamp Blood DNA midi kit from 32 maternal (12-37 weeks) plasma. Using the nested polymerase chain reaction (PCR), the 130 bp SRY gene-specific sequence and the 261 bp ATL1 gene-specific sequence were amplified simultaneously. The results were confirmed by examination of newborns after delivery. Multiplex polymerase chain reaction amplification at sixteen different polymorphic short tandem repeat (STR) loci was also used to detect the fetal DNA in maternal plasma.Results The concordance rate between real fetal sex and sex determined by amplification of the SRY gene was 94% (30/32). The paternally inherited fetal alleles were detected by short tandem repeat detection in all cases. Conclusion Circulating fetal DNA analysis can be used as a possible alternative tool in routine laboratory prenatal diagnosis in the near future.