两种遗传标记系统鉴定母血中有核红细胞来源

Determination of fetal nucleated erythrocytes circulating in maternal peripheral blood using two separate systems of genetic markers.

目的探讨母血中胎儿有核红细胞的鉴定方法及其对无创性产前诊断的意义。方法86例孕妇外周血,以血红蛋白γ链染色结合显微操作分离获取胎儿有核红细胞。经PEP扩增胎儿细胞基因组后,共70例进行SRY基因检测;32例进行X-STR位点DXS101、DXS6797分析并与双亲基因型对比,判断模板细胞来源及胎儿性别。结果所有孕妇血样均检出胎儿有核红细胞。SRY基因判断胎儿性别的准确率为97.14%(68/70)。联用DXS101、DXS6797对胎儿细胞鉴定及性别判断的准确率达100%(32/32)。16例同时接受2种方法,检测结果均一致。结论采用SRY基因或多X-STR位点作为母血中胎源细胞鉴定系统,两种方法均能有效判断细胞来源,且各有优缺点,两者结合将有更广阔的应用前景。

Objective： To evaluate two methods of detection of fetal nucleated red blood ceils in maternal circulation and their applicability in noninvasive prenatal diagnosis. Methods： 86 peripheral blood samples were obtained from pregnant women. Fetal nucleated erythrocytes were discerned by heamoglobin γ chain staining and micromanipulated separately. After primer extension preamplification （PEP）, single candidate cells from 70 cases were subjected to amplification of SRY gene, and 32 cases accepted analysis of two X - （DXS101, DXS6797） in which fetal sex was judged by comparing the genotype of fetus with those of its parents. 16 samples accepted both SRY gene and STR loci detection. Results ： Fetal nucleated red blood cells were obtained from all samples. The accurate rate of detecting SRY gene was 97. 14% （68/70）. And fetal sex was accurately diagnosed in each case by analysis of DXS101 and DXS6797, with a concordance rate of 100% （32/32）. The results of two methods for the same case were in coincidence with each other. Conclusion ： SRY gene and multiple X - specific STRs are both effective markers in confirmation of fetal cells in maternal blood. As each system has its own advantages and disadvantages, it is suggested that association of them may gain wider use in noninvasive prenatal diagnosis.