Fetal DNA In Maternal Circulation Research Articles

A-339 Utomated Flow of a Non-invasive Fetal Gender Determination Lab-developed Molecular Test

Abstract Background The discovery of cell-free fetal DNA in maternal circulation during pregnancy fostered the introduction of non-invasive tests. Fetal gender determination may be determined at early pregnancy by real-time PCR, identifying the presence or absence of Y chromosome markers in maternal plasma. Dasa has been offering this test for more than 10 years. In 2022, the assay was adapted to an automated flow. Methods The Flow Solution platform, powered by Roche®, was adapted to the in-house test, allowing the processing of 94 samples. Whole blood is obtained from pregnant women from the 8th week of pregnancy onwards. Each maternal plasma sample is extracted once and the DNA eluate submitted to real-time amplification targeting the DYS14 gene from the Y chromosome, in triplicate. The human RNAseP gene is co-amplified as an internal control. Full process takes 5 hours, with the possibility of overlapping a new routine every 2 hours, with a daily capacity of 12 routines (1128 samples/day). Results In 2022, 129 849 fetal gender determination results were released. Of these, 49% of the results indicated male and 51% female fetuses.A few samples displayed indeterminate results, showing amplification curves but with cycle threshold values that are above the cutoff. Other samples do not reach internal quality metrics and the analysis is repeated from the plasma or a new collection is requested. Results that, after the second collection, remain indeterminate, are forwarded with the patient's clinical history to the medical board. In contact with the patient, possible causes for inconclusive results are explained. In 2022, for every 10 000 tests there were 8 were medical contacts.The automated methodology developed and implemented, allowed a high processing volume, with 129 849 tests released in 2022, an increase of 33% compared to 2021 when the method had manual steps. The Total Service Time (TST) from collection to results release in 2022 was approximately 5 days, a 20% reduction compared to 2021, and the repetition rate of 2.43% in 2022 was 0.9% lower than 2021. Recollections also diminished from 1% in 2021 falling to 0.8% in 2022. Conclusion A new automated flow was successfully implemented in 2022 improving the productivity and quality of the service, achieving a high accuracy and leading to a significant reduction in errors and repetitions while reducing the turnaround time and recollections.

Vers une généralisation du diagnostic prénatal non-invasif des maladies monogéniques ? État des lieux et perspectives

The screening of fetal aneuploidies and non-invasive prenatal diagnosis of monogenic diseases (NIPD-MD) both rely on the study of free fetal DNA in maternal circulation, but their respective rise was unequal. Development of NIPD-MD has taken longer as it represents a less attractive commercial dynamic for industry, but also because it usually involves the development of tailored tests specific to each pathogenic variant. We have carried out a review of the literature on the various indications and technologies involved in the use of NIPD-MM. We present its current implementation and its development in France. To date, NIPD-MD has been routinely offered in France for several years by the laboratories of the French NIPD-MD network but remains mostly limited to the exclusion of paternal or de novo variants, the exclusion DPNI-MD. Indeed, it is still difficult to study the transmission of maternal variants from circulating free DNA analysis, due to its biological complexity: coexistence and predominance of similar DNA sequences of maternal origin. Different strategies, either direct or indirect, are being evaluated to establish fetal status regardless of the parental origin of the disease or its transmission mode. The emergence of commercial screening solutions for monogenic diseases complements the arsenal of prenatal exploration tools for these diseases. The multitude of existing technologies and protocols may complicate the information provided during antenatal consultations, but mastery of know-how and knowledge of ethical issues of NIPD-MD will ensure optimal service and better management of pregnancies at risk of transmitting monogenic disease.

Methods of detection and isolation of trophoblast cells from trans-cervical specimens – a historical overview

Abstract Trophoblast cells can be detected and isolated from the cervical epithelial cells obtained via various techniques of trans-cervical samples collection such as a mucus aspiration, endocervical lavage, or standard cervical brushing in the early first trimester, even from the 5 weeks’ gestation. Isolated fetal cells can be used in the early prediction of fetal sex, prenatal diagnostics of the most common aneuploidies, and any other genetic abnormalities. Nevertheless, the collection of trophoblastic cells has limited efficacy compared to currently used methods of detection of free fetal DNA in maternal circulation or other protocols of invasive prenatal diagnostics available at later stages of pregnancy. In the past years, trans-cervical cell samples were collected mainly in women before planned pregnancy termination. The early trophoblastic cells isolation from women in ongoing pregnancies opens new perspectives for further studies focused on the elucidation of pathophysiology of numerous pregnancy-related complications.

Non-invasive Prenatal Diagnosis of β-Thalassemia by Detection of the Cell-Free Fetal DNA in Maternal Circulation

β-thalassemia is one of the most frequent autosomal recessive diseases that has a high recurrence in people of the Mediterranean zone, the Middle East, Tropical Africa, and the Caribbean. Parents who are both carriers for β-thalassemia have a 25% danger to give a child with β-thalassemia major. The most accessible strategies for pre-birth diagnosis are chorionic villus sampling (CVS) somewhere in the range of 11 and 14 weeks and amniocentesis following 15 weeks and both are invasive procedures and cause dangers to the fetus and mother, having a danger of abortion 1 in 100–200 and 1 in 200–400, respectively. The accuracy of these methods is estimated to be 98–99%. Cell-free fetal DNA (cff-DNA) can be found in maternal plasma following 18 days from fertilized egg implantation in Pregnancies after lab conception and resembles extracellular DNA. The discovery of cff-DNA in maternal plasma has led to the evolution of noninvasive prenatal diagnosis(NIPND). Some genomic loci of cff-DNA show methylated sequences unique in relation to circling maternal DNA, this trademark can be utilized to evaluate and demonstrate the presence of fetal DNA during pregnancy, independent of the sex of the embryo. the two major limitations for (NIPND) are the small amount of cff-DNA in maternal blood and its co-existence with maternal free DNA.we study investigations used in the detection of inherited mutation of β-thalassemia in maternal plasma during pregnancy using cell-free fetal DNA and evaluate the diagnostic test performance of cff-DNA for this issue.

Prenatal screening for chromosomal abnormalities in IVF patients that opted for preimplantation genetic screening/diagnosis (PGS/D): a need for revised algorithms in the era of personalized medicine.

Obstetricians offer prenatal screening for most common chromosomal abnormalities to all pregnant women including those that had in vitro fertilization (IVF) and preimplantation genetic screening/diagnosis (PGS/D). We propose that free fetal DNA in maternal circulation together with the second trimester maternal serum alfa feto protein (MSAFP) and ultrasound imaging is the best prenatal screening test for chromosomal abnormalities and congenital anomalies in IVF-PGD/S patients because risk estimations from all other prenatal screening algorithms for chromosomal abnormalities depend heavily on maternal age which is irrelevant in PGS/D patients.

Non-invasive prenatal diagnosis of β-thalassemia by detection of the cell-free fetal DNA in maternal circulation: a systematic review and meta-analysis.

The discovery of fetal DNA (f-DNA) opens the possibility of early non-invasive procedure for detection of paternally inherited mutation of beta-thalassemia. Since 2002, some studies have examined the sensitivity and specificity of this method for detection of paternally inherited mutation of thalassemia in pregnant women at risk of having affected babies. We conducted a systematic review of published articles that evaluated using this method for early detection of paternally inherited mutation in maternal plasma. A sensitive search of multiple databases was done in which nine studies met our inclusion criteria. The sensitivity and specificity was 99 and 99%, respectively. The current study found that detection of paternally inherited mutation of thalassemia using analysis of cell-free fetal DNA is highly accurate. This method could replace conventional and invasive methods.

Cell free fetal DNA in the plasma of pregnant women with preeclampsia

Objective: Insufficient cytotrophoblast invasion to the myometrium is associated with preeclampsia, especially with the early-onset preeclampsia (before 34 gestational weeks). Several investigations have marked changes in the concentration of cell free fetal DNA in the maternal circulation of women with preeclampsia. However, these studies were not performed for early or late preeclampsia subgroups individually. The present authors planned to determine the levels of the cell free both fetal and maternal DNA in the maternal circulation in early preeclampsia subgroup and compare it with normotensive control cohort. Materials and Methods: A total of 16 women; eight of these with preeclampsia and eight normotensive control cohorts with singleton male pregnancy between 28 and 32 gestational weeks were included in the study. Real-time PCR analysis was performed for determining the circulating cell free DNA levels. Results: Cell free fetal DNA concentrations were higher in early preeclamptic women than control subjects. The authors found no statistically significant difference in each levels of maternal and total DNA between hypertensive and normotensive groups. Conclusions: The present findings suggest that the levels of cell free fetal DNA in maternal circulation were higher in pregnancies which are complicated with early preeclampsia than normotensive controls.

Does rat fetal DNA induce preeclampsia in pregnant rats?

Cell-free fetal DNA in maternal circulation is higher during preeclampsia. It is unclear whether it is the cause or the consequence of the disease. The aim of this study was to prove whether injected rat fetal DNA induces preeclampsia-like symptoms in pregnant Wistar rats. They received daily i.p. injections of water or rat fetal DNA (400 μg) from gestation day 14 to 18. Blood pressure, proteinuria, placental and fetal weight were measured at gestation day 19. Plasma DNase activity, proteinuria and creatinine clearance were assessed. There was no significant difference in any of the measured parameters. The results of this study do not confirm the hypothesis that fetal DNA might induce preeclampsia. This is in contrast to others using human fetal DNA in mice. Further studies should be focused on the effects of fetal DNA from the same species protected from DNase activity.

96: Quantification of cell free fetal DNA in maternal circulation as a marker of adverse pregnancy outcomes

96: Quantification of cell free fetal DNA in maternal circulation as a marker of adverse pregnancy outcomes

Prenatal Diagnosis of Hemoglobinopathies: From Fetoscopy to Coelocentesis

Prenatal diagnosis of hemoglobinopathies involves the study of fetal material from blood, amniocytes, trophoblast coelomatic cells and fetal DNA in maternal circulation. Its first application dates back to the 70s and it involves globin chain synthesis analysis on fetal blood. In the 1980s molecular analysis was introduced as well as amniocentesis and chorionic villi sampling under high-resolution ultrasound imaging. The application of direct sequencing and polymerase chain reactionbased methodologies improved the DNA analysis procedures and reduced the sampling age for invasive prenatal diagnosis from 18 to 16–11 weeks allowing fetal genotyping within the first trimester of pregnancy. In the last years, fetal material obtained at 7–8 weeks of gestation by coelocentesis and isolation of fetal cells has provided new platforms on which to develop diagnostic capabilities while non-invasive technologies using fetal DNA in maternal circulation are starting to develop.

A New Era in Prenatal Diagnosis: The Use of Cell-Free Fetal DNA in Maternal Circulation for Detection of Chromosomal Aneuploidies

Prenatal screening for chromosomal aneuploidies is a fundamental part of routine obstetric care in most countries. Typically, maternal age, weight, ethnicity, serum biomarkers (including pregnancy-associated plasma protein A, human chorionic gonadotropin, α-fetoprotein, inhibin A, and estriol), and sonographic features (i.e., nuchal translucency) are included in a risk algorithm to determine the probability of the fetus being affected. Pregnant women identified as at high risk according to the prenatal screen can then undergo invasive procedures, such as amniocentesis and chorionic villus sampling, to confirm the diagnosis. Current prenatal-screening methods are able to identify approximately 90% of pregnancies affected by trisomy 21 (Down syndrome) at a false-positive rate of approximately 5%. Given that the prevalence of chromosomal aneuploidies is generally quite low, a false-positive rate of 5% means that a large number of women with unaffected pregnancies undergo invasive procedures, putting the fetus at an unnecessary risk for miscarriage. The discovery of fetal cell-free DNA in the plasma of pregnant women 14 years ago opened up the possibility of identifying chromosomal abnormalities noninvasively, through a single blood sample. Approximately 10% of cell-free DNA in the maternal circulation is of fetal origin, and this property was initially exploited to determine rhesus D status and the sex of the unborn fetus. The advent of next-generation DNA sequencing, however, has allowed prenatal detection of chromosomal aneuploidies, including trisomy 21, from maternal blood. In brief, the proportion of chromosome 21 DNA molecules in maternal plasma is measured directly; an increase above a predetermined threshold is indicative of trisomy 21. The clinical performance of this noninvasive prenatal test has been promising, with recent clinical studies having shown a diagnostic sensitivity of 100% and a diagnostic specificity of 98%–99%, compared with full karyotyping by invasive means. When used as a second-tier screening procedure, this technology also has the …

Non-invasive prenatal diagnosis from the perspective of a low-resource country

Current clinical practice in obstetrics has shifted the paradigm from a conventional prenatal approach based on invasive procedures, risking both fetus and mother, to non-invasive prenatal testing for some fetal conditions via the analysis of cell-free fetal DNA in maternal blood. In the past 15years, much research has been devoted to refining the methodology for measuring cell-free fetal DNA in maternal circulation and to exploring clinical applications of this technology as a potential tool for prenatal diagnosis. Since the rapid spread around the world of prenatal diagnosis based on cell-free fetal DNA, it is time to start thinking how this cutting-edge technology might influence current practice of obstetrics in low-resource countries.

Cell‐free fetal DNA in maternal circulation after chorionic villous sampling

This study aims to estimate whether chorionic villous sampling (CVS) causes a significant increase of cell-free fetal DNA (cffDNA) in maternal circulation. Fifty pregnant women with singleton pregnancy were recruited prior to CVS. Maternal peripheral blood was collected before and after CVS. A methylation-sensitive restriction enzyme digestion was used to select the placental-derived hypermethylated promoter of the RASSF1A gene in maternal plasma, thus differentiating cffDNA from mother's cell-free DNA (cfDNA), where the RASSF1A gene is normally hypomethylated. Total cfDNA and cffDNA amounts were compared before and after CVS in each patient. Data were compared using the Student t-test. No significant difference before and after CVS was found between the following: (i) total cfDNA concentration in plasma (p = 0.695); (ii) cffDNA concentration in plasma (p = 0.612); and (iii) percentage of fetal DNA in plasma (p = 0.835). After dividing the cases on the basis of the sex of the fetus, maternal age, gestational age, number of pregnancies, position of the placenta, and presence of trisomy of the fetus, no difference in fetal and total DNA concentrations before and after CVS was observed. The CVS does not seem to significantly disrupt the maternal-placental interface, as no significant increase of cffDNA in maternal plasma following CVS was observed.

ACMG statement on noninvasive prenatal screening for fetal aneuploidy

Noninvasive assessment of the fetal genome is now possible using next-generation sequencing technologies. The isolation of fetal DNA fragments from maternal circulation in sufficient quantity and sizes, together with proprietary bioinformatics tools, now allows patients the option of noninvasive fetal aneuploidy screening. However, obstetric care providers must become familiar with the advantages and disadvantages of the utilization of this approach as analysis of cell-free fetal DNA moves into clinical practice. Once informed, clinicians can provide efficient pretest and posttest counseling with the goal of avoiding patient harm. It is in the public's best interest that test results contain key elements and that laboratories adhere to established quality control and proficiency testing standards. The analysis of cell-free fetal DNA in maternal circulation for fetal aneuploidy screening is likely the first of major steps toward the eventual application of whole fetal genome/whole fetal exome sequencing.

Prenatal screening methods for aneuploidies

Aneuploidies are a major cause of perinatal morbidity and mortality. Therefore, it is the most common indication for invasive prenatal diagnosis. Initially, screening for aneuploidies started with maternal age risk estimation. Later on, serum testing for biochemical markers and ultrasound markers were added. Women detected to be at high-risk for aneuploidies were offered invasive testing. New research is now focusing on non-invasive prenatal testing using cell-free fetal DNA in maternal circulation. The advantage of this technique is the ability to reduce the risk of miscarriage associated with invasive diagnostic procedures. However, this new technique has its own set of technical limitations and ethical issues at present and careful consideration is required before broad implementation

Analysis of the earliest appearance of cell free fetal DNA in maternal circulation

Cell free fetal (CFF) DNA in the maternal circulation represents a readily available source of material to investigate the genetic status of the fetus. As molecular technologies improve, CFF testing will allow earlier and less invasive evaluation of a variety of disorders including single gene defects. The stage of development when sufficient CFF is present to allow meaningful testing has not been determined. ART provides a precise model as gestational age (GA) is unequivocally established. This study seeks to determine when sufficient CFF DNA may be present in detectable quantities.

Uses of cell free fetal DNA in maternal circulation

For over a decade, researchers have focused their attention on the development of non-invasive prenatal diagnosis tests based on cell-free fetal DNA circulating in maternal blood. With the possibility of earlier and safer testing, non-invasive prenatal diagnosis has the potential to bring many positive benefits to prenatal diagnosis. Non-invasive prenatal diagnosis for fetal sex determination for women who are carriers of sex-linked conditions is now firmly established in clinical practice. Other non-invasive prenatal diagnosis-based tests are set to follow, as future applications, suchas the detection of single-gene disorders and chromosomal abnormalities, are now well within reach. Here, we review recent developments in non-invasive prenatal diagnosis for genetic conditions and chromosomal abnormalities, and provide an overview of research into ethical concerns, social issues and stakeholder view points.

Relative quantitation of cell-free fetal DNA in maternal plasma using autosomal DNA markers

BackgroundCell-free fetal DNA in maternal plasma presents interest as it can possibly serve as a pregnancy associated biomarker. For its quantitation, we investigate the use of fluorescent polymerase chain reaction (PCR) amplification of short tandem repeats (STRs) in pregnancies irrespective of sex. MethodsArtificially chimeric DNA samples were prepared so as to simulate cell-free fetal DNA in maternal plasma at different proportions. The samples were tested with fluorescent PCR amplification of informative STRs and the percentage of the population simulating fetal DNA was plotted against a relative ratio of the alleles detected in each sample. The graphs were used for the quantitation of cell-free fetal DNA in 50 maternal plasma samples. ResultsDetection of at least one paternally inherited fetal STR was possible in 46/50 pregnancies leading to the estimation of the relative percentage of cell-free fetal DNA. Four pregnancies failed to reveal any fetal allele which may reflect undetectable levels (<1%) of fetal DNA. Among pregnancies fetal DNA ranged from 0 to 20% (mean value of 7%). ConclusionOur system can readily estimate the relative levels of cell-free fetal DNA in maternal circulation, normal gestations of either sex and can be exploited for estimating possible variations of this analyte between normal and pathological pregnancies.

877 Measuring the level of genomic distortion in breast tumours with increasing histological grade – aprogression model

Current clinical practice in obstetrics has shifted the paradigm from a conventional prenatal approach based on invasive procedures, risking both fetus and mother, to non-invasive prenatal testing for some fetal conditions via the analysis of cell-free fetal DNA in maternal blood. In the past 15 years, much research has been devoted to refining the methodology for measuring cell-free fetal DNA in maternal circulation and to exploring clinical applications of this technology as a potential tool for prenatal diagnosis. Since the rapid spread around the world of prenatal diagnosis based on cell-free fetal DNA, it is time to start thinking how this cutting-edge technology might influence current practice of obstetrics in low-resource countries.

Genomic Medicine in Prenatal Diagnosis

Prenatal diagnostics has seen a rapid increase in the number of genetic disorders amenable to prenatal detection owing to advances in technology and research into the genetic etiology of many conditions. This article reviews the more traditional prenatal diagnostic techniques, such as amniocentesis and chorionic villus sampling for chromosome abnormalities and single gene disorders, and chromosome analysis of products of conception to determine the etiology of a spontaneous abortion, plus more recent advances such as rapid aneuploidy detection via fluorescence in situ hybridization and polymerase chain reaction, preimplantation genetic diagnosis, noninvasive analysis of cell-free fetal DNA in maternal circulation, and array-based comparative genomic hybridization.