Kinetics of SRY gene appearance in maternal serum: detection by real time PCR in early pregnancy after assisted reproductive technique

Abstract

Fetal DNA is found in maternal serum even before the fetal circulation is established, which is highly suggestive that it is released, at least in part, from the trophoblast. Detection of fetal DNA in maternal serum very early in pregnancy may have clinical implications such as with the management of pregnant women carrying a fetus at risk for congenital adrenal hyperplasia.

Accurate and Robust Quantification of Circulating Fetal and Total DNA in Maternal Plasma from 5 to 41 Weeks of Gestation

“…Most subsequent investigations have focused on a particular trimester (15,16 ), and more recently, fetal DNA has been detected as early as 5 weeks of gestation (17,18 ). However, few groups have monitored the concentrations of both fetal and total DNA in maternal plasma across all three trimesters or included the steps taken to ensure accurate quantification.…”

Prenatal diagnosis: progress through plasma nucleic acids

“…For one thing, paleopolyploid events might be too infrequent 4 . The most recent polyploidy event in the evolutionary lineage of Arabidopsis thaliana occurred anywhere from 25 million years to 100 million years ago 5,6 , too long ago to contribute to differences in genome size and chromosomal number between A. thaliana and its closest relatives.…”

“…The first demonstration of the presence of cell-free fetal DNA in the plasma of pregnant women was the detection of Y-chromosomal DNA cell-free DNA that is present in maternal plasma 5 . The earliest gestational age at which circulating fetal DNA is detectable in maternal plasma is day 18 after embryo transfer by assisted reproduction 6 . Fetal DNA concentrations seem to increase as gestation progresses 5 ; following delivery, fetal DNA is cleared extremely rapidly from maternal plasma, with a mean half-life of about 16 minutes 7 .…”

Cell-Free Fetal DNA in Prenatal Screening

“…Bu "fetal fraksiyon" en erken beşinci gebelik haftasından itibaren saptanebilmekle beraber, dokuzuncu gebelik haftasından itibaren yeterli düzeylere ulaş-maktadır. 10 Yirminci gebelik haftasına kadar daha yavaş olarak (haftada yaklaşık %0,1) artış gösteren bu kısım, 20. haftadan sonra hızla (haftada yaklaşık %1,0) artmaktadır. 11 Fetal fraksiyonun %4'ün altında olması yetersiz olarak kabul edilmekte ve test sonuç-suzluğunun en önemli nedenini oluşturmaktadır.…”