孕DOWN综合征胎儿妇女血浆游离胎儿DNA浓度定量研究

Quantitative analysis of cell-free fetal DNA levels in maternal plasma with DOWN syndrome and normal pregnancies.

目的探讨实时定量PCR方法检测妊娠DOWN综合征胎儿妇女血浆游离胎儿DNA的可行性。方法SRY基因为胎儿游离DNA的标志，应用实时定量PCR分别检测10例妊娠DOWN综合征胎儿（男胎7例，女胎3例）妇女与20例妊娠正常胎儿（男胎14例，女胎6例）妇女血浆标本中游离胎儿DNA含量。结果7例妊娠DOWN综合征男胎妇女SRY基因当量为（318．03±96．74）拷贝／ml（95％可信区间228．26—407．50拷贝／ml），妊娠正常男胎组SRY基因当量为（154．40±39．43）拷贝／ml（95％可信区间131．63～177．16拷贝／ml）；2组差异有统计学意义（t=3．33，P=0．004）。妊娠女胎组妇女血浆中SRY基因当量均为0拷贝／ml。结论妊娠DOWN综合征男胎儿妇女血浆游离胎儿DNA的量较妊娠正常男胎儿妇女高。

Objective To investigate the application of real-time quantitative PCR in quantification of cellfree fetal DNA maternal plasma in patients bearing fetuses affected with DOWN syndrome. Methods Cell-free fetal DNA in maternal serum was isolated from 30 samples（7 male DOWN syndrome fetal,3 female DOWN syndrome fetal,14 male euploid fetal,6 female euploid fetal）. Cell-free fetal DNA levels in maternal serum were measured using real-time quantitative PCR using SRY as marker. Results The median cell-free fetal DNA levels in pregnant carrying male fetuses（n =7） and the controls（pregnant carrying male euploid fetuses,n = 14）were 318.03 ±96.74 genome-equivalents/ml and 154.40 ± 39.43 genome-equivalents/ml of maternal serum, respectively （ t = 3.33, P = 0.004 ）, which was o in women with female fetuses. Conclusion The cell-free fetal DNA levels in pregnant women with DOWN syndrome fetuses are higher than that in pregnant women with normal fetuses.