Alberry M, Maddocks D, Jones M, Abdel Hadi M, Abdel-Fattah S, Avent N, Soothill P W
St. Michael's Hospital, Southwell Street, Bristol, UK.
Prenat Diagn. 2007 May;27(5):415-8. doi: 10.1002/pd.1700.
To test the hypothesis that free fetal DNA (ffDNA) circulating in maternal plasma originates mainly from the placenta we studied ffDNA levels in anembryonic pregnancies.
Maternal blood samples were collected from 15 normal first-trimester pregnancies in which fetal sex was subsequently determined and nine patients with a diagnosis of anembryonic gestation (AG). The Y chromosome DYS14 gene was quantified by real-time quantitative PCR (RT-PCR) for the determination of fetal sex in both plasma and chorionic tissue samples. Fetal sex in chorionic tissue samples was also determined using quantitative fluorescence PCR (QF-PCR).
The correct sex result was obtained from maternal plasma in all. Four AG pregnancies were female (DYS14 negative) results. In five of the AG cases, the chorionic tissue was found to be male (by both QF-PCR and RT-PCR which agreed) and positive male signal was found in maternal plasma by RT-PCR. There was no statistical difference between median free fetal DNA concentration in plasma between the AG male cases (148.3 GE/mL) and controls (145.8 GE/mL).
Since ffDNA levels are normal in pregnancies without a fetus, the data support the hypothesis that the trophoblastic cells are the major source ffDNA in maternal plasma.
为验证母血中循环的游离胎儿DNA（ffDNA）主要来源于胎盘这一假说，我们研究了空孕囊妊娠中的ffDNA水平。
采集了15例正常早孕孕妇的母血样本，这些孕妇随后均确定了胎儿性别，同时采集了9例诊断为空孕囊妊娠（AG）患者的母血样本。通过实时定量PCR（RT-PCR）对血浆和绒毛组织样本中的Y染色体DYS14基因进行定量，以确定胎儿性别。绒毛组织样本中的胎儿性别也采用定量荧光PCR（QF-PCR）进行测定。
所有孕妇血浆中均获得了正确的性别结果。4例AG妊娠为女性（DYS14阴性）结果。在5例AG病例中，绒毛组织经QF-PCR和RT-PCR检测均显示为男性，且RT-PCR在母血中检测到阳性男性信号。AG男性病例血浆中游离胎儿DNA浓度中位数（148.3 GE/mL）与对照组（145.8 GE/mL）之间无统计学差异。
由于无胎儿妊娠中ffDNA水平正常，数据支持滋养层细胞是母血中ffDNA主要来源的假说。
