应用巢式PCR检测母体尿液中胎儿遗传信息

Detection of targeted fetal DNA in urine with nested PCR for non-invasive prenatal diagnosis

目的依据孕妇血浆中存在游离胎儿DNA的理论,评价从母体尿液中分离游离胎儿DNA的可行性及其在临床应用的可行性。方法提取41例健康孕妇尿液标本中游离胎儿DNA,经巢式PCR扩增其性别决定基因(sex-determ in ingregion Y,SRY),并引入X染色体上特异的内参照基因序列ATL1,同时以其丈夫及未孕女性的外周血作对照分析。结果 41例孕妇所孕胎儿22例为男性,19例为女性。22例怀有男胎孕妇尿液标本经SRY扩增后,8例为阳性,其中6例第1、2次扩增均为阳性,2例第2次扩增后方出现阳性扩增带;其余14例怀有男胎孕妇和19例怀有女胎孕妇尿液标本扩增结果均为阴性。结论孕妇尿液中的确存在着游离胎儿DNA,需进一步提高其检出阳性率。

Objective：To explore the application of fetal DNA in urine for non-invasive prenatal diagnosis.Methods： The DNA template was extracted by QIAamp Blood DNA midi kit from 41 maternal（39±2weeks） urine.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.Results： In 19 samples from female-bearing pregnant women,the SRY gene was not detected in any cases,with a false-positive rate of 0 while 22 samples from male-bearing pregnant women,the SRY gene was detected in 8 cases.The positive rate of detection of SRY gene was 36.33%（8/ 22） and the false negative rate was 55.55% while false positive rate was 0.6 out of the 8 cases with positive results showed positive for 2 times and two out of the 8 cases only showed positive at the second time.Conclusion： Circulating fetal DNA in urine can be used as a possible alternative tool in detection of fetal sex,however,still with a rather low positive rate.