Comprehensive Recommendations for the Clinical Management of Pregnant Women With Noninvasive Prenatal Test Results Suspicious of a Maternal Malignancy.

In this article, we defined comprehensive recommendations for the clinical follow-up of pregnant women with a malignancy-suspicious NIPT result, on the basis of the vast experience with population-based NIPT screening programs in two European countries complemented with published large data sets. These recommendations provide a tool for classifying NIPT results as malignancy-suspicious, and guide health care professionals in structured clinical decision making for the diagnostic process of pregnant women who receive such a malignancy-suspicious NIPT result.

Early detection of active Human CytomegaloVirus (hCMV) infection in pregnant women using data generated for noninvasive fetal aneuploidy testing.

BACKGROUND: Prenatal hCMV infections can lead to severe embryopathy and neurological sequelae in neonates. Screening during pregnancy is not recommended by global societies, as there is no effective therapy. Recently, several groups showed that maternal-fetal hCMV transmission can be strongly reduced by administering anti-viral agents early in pregnancy. This calls for a screening method to identify at risk pregnancies at an appropriate gestational age, with the possibility for large-scale enrolment. Non-Invasive Prenatal Testing (NIPT) for fetal aneuploidy screening early in pregnancy is already implemented in many countries and performed on a large-scale basis. We investigated the use of whole genome cell-free DNA (cfDNA) sequencing data, generated for the purpose of NIPT, as (pre-)screening tool to identify women with active hCMV-infections, eligible for therapy. METHODS: Coded raw sequencing NIPT data from 204,818 pregnant women from three testing laboratories were analyzed for the presence of hCMV-cfDNA. Samples were stratified by cfDNA-hCMV load. For validation and interpretation, diagnostic hCMV-qPCR and serology testing were performed on a subset of cfDNA-hCMV-positive (n = 112) and -negative (n = 127) samples. FINDINGS: In 1930 samples (0.94%) hCMV fragments were detected. Validation by hCMV-qPCR showed that samples with high cfDNA-hCMV load tested positive and cfDNA-hCMV-negative samples tested negative. In 32/112 cfDNA-hCMV-positive samples (28.6%) the serological profile suggested a recent primary infection: this was more likely in samples with high cfDNA-hCMV load (78.6%) than in samples with low cfDNA-hCMV load (11.0%). In none of the cfDNA-hCMV-negative samples serology was indicative of a recent primary infection. INTERPRETATION: Our study shows that large-scale (pre-)screening for both genetic fetal aberrations and active maternal hCMV infections during pregnancy can be combined in one cfDNA sequencing test, performed on a single blood sample, drawn in the first trimester of pregnancy. FUNDING: This work was partly funded by the Prenatal Screening Foundation Nijmegen, the Netherlands.

Fetal fraction of cell-free DNA in noninvasive prenatal testing and adverse pregnancy outcomes: a nationwide retrospective cohort study of 56,110 pregnant women.

BACKGROUND: Noninvasive prenatal testing by cell-free DNA analysis is offered to pregnant women worldwide to screen for fetal aneuploidies. In noninvasive prenatal testing, the fetal fraction of cell-free DNA in the maternal circulation is measured as a quality control parameter. Given that fetal cell-free DNA originates from the placenta, the fetal fraction might also reflect placental health and maternal pregnancy adaptation. OBJECTIVE: This study aimed to assess the association between the fetal fraction and adverse pregnancy outcomes. STUDY DESIGN: We performed a retrospective cohort study of women with singleton pregnancies opting for noninvasive prenatal testing between June 2018 and June 2019 within the Dutch nationwide implementation study (Trial by Dutch Laboratories for Evaluation of Non-Invasive Prenatal Testing [TRIDENT]-2). Multivariable logistic regression analysis was used to assess associations between fetal fraction and adverse pregnancy outcomes. Fetal fraction was assessed as a continuous variable and as <10th percentile, corresponding to a fetal fraction <2.5%. RESULTS: The cohort comprised 56,110 pregnancies. In the analysis of fetal fraction as a continuous variable, a decrease in fetal fraction was associated with increased risk of hypertensive disorders of pregnancy (adjusted odds ratio, 2.27 [95% confidence interval, 1.89-2.78]), small for gestational age neonates <10th percentile (adjusted odds ratio, 1.37 [1.28-1.45]) and <2.3rd percentile (adjusted odds ratio, 2.63 [1.96-3.57]), and spontaneous preterm birth from 24 to 37 weeks of gestation (adjusted odds ratio, 1.02 [1.01-1.03]). No association was found for fetal congenital anomalies (adjusted odds ratio, 1.02 [1.00-1.04]), stillbirth (adjusted odds ratio, 1.02 [0.96-1.08]), or neonatal death (adjusted odds ratio, 1.02 [0.96-1.08]). Similar associations were found for adverse pregnancy outcomes when fetal fraction was <10th percentile. CONCLUSION: In early pregnancy, a low fetal fraction is associated with increased risk of adverse pregnancy outcomes. These findings can be used to expand the potential of noninvasive prenatal testing in the future, enabling the prediction of pregnancy complications and facilitating tailored pregnancy management through intensified monitoring or preventive measures.

Prevalence of chromosomal alterations in first-trimester spontaneous pregnancy loss.

Pregnancy loss is often caused by chromosomal abnormalities of the conceptus. The prevalence of these abnormalities and the allocation of (ab)normal cells in embryonic and placental lineages during intrauterine development remain elusive. In this study, we analyzed 1,745 spontaneous pregnancy losses and found that roughly half (50.4%) of the products of conception (POCs) were karyotypically abnormal, with maternal and paternal age independently contributing to the increased genomic aberration rate. We applied genome haplarithmisis to a subset of 94 pregnancy losses with normal parental and POC karyotypes. Genotyping of parental DNA as well as POC extra-embryonic mesoderm and chorionic villi DNA, representing embryonic and trophoblastic tissues, enabled characterization of the genomic landscape of both lineages. Of these pregnancy losses, 35.1% had chromosomal aberrations not previously detected by karyotyping, increasing the rate of aberrations of pregnancy losses to 67.8% by extrapolation. In contrast to viable pregnancies where mosaic chromosomal abnormalities are often restricted to chorionic villi, such as confined placental mosaicism, we found a higher degree of mosaic chromosomal imbalances in extra-embryonic mesoderm rather than chorionic villi. Our results stress the importance of scrutinizing the full allelic architecture of genomic abnormalities in pregnancy loss to improve clinical management and basic research of this devastating condition.

A cross-country comparison of pregnant women's decision-making and perspectives when opting for non-invasive prenatal testing in the Netherlands and Belgium.

BACKGROUND: The Netherlands and Belgium have been among the first countries to offer non-invasive prenatal testing (NIPT) as a first-tier screening test. Despite similarities, differences exist in counseling modalities and test uptake. This study explored decision-making and perspectives of pregnant women who opted for NIPT in both countries. METHODS: A questionnaire study was performed among pregnant women in the Netherlands (NL) (n = 587) and Belgium (BE) (n = 444) opting for NIPT, including measures on informed choice, personal and societal perspectives on trisomy 21, 18 and 13 and pregnancy termination. RESULTS: Differences between Dutch and Belgian women were shown in the level of informed choice (NL: 83% vs. BE: 59%, p < 0.001), intention to terminate the pregnancy in case of confirmed trisomy 21 (NL: 51% vs. BE: 62%, p = 0.003) and trisomy 13/18 (NL: 80% vs. BE: 73%, p = 0.020). More Belgian women considered trisomy 21 a severe condition (NL: 64% vs. BE: 81%, p < 0.001). Belgian women more frequently indicated that they believed parents are judged for having a child with trisomy 21 (BE: 42% vs. NL: 16%, p < 0.001) and were less positive about quality of care and support for children with trisomy 21 (BE: 23% vs. NL: 62%, p < 0.001). CONCLUSION: Differences in women's decision-making regarding NIPT and the conditions screened for may be influenced by counseling aspects and country-specific societal and cultural contexts.

All-in-one whole exome sequencing strategy with simultaneous copy number variant, single nucleotide variant and absence-of-heterozygosity analysis in fetuses with structural ultrasound anomalies: A 1-year experience.

OBJECTIVE: We performed a 1-year evaluation of a novel strategy of simultaneously analyzing single nucleotide variants (SNVs), copy number variants (CNVs) and copy-number-neutral Absence-of-Heterozygosity from Whole Exome Sequencing (WES) data for prenatal diagnosis of fetuses with ultrasound (US) anomalies and a non-causative QF-PCR result. METHODS: After invasive diagnostics, whole exome parent-offspring trio-sequencing with exome-wide CNV analysis was performed in pregnancies with fetal US anomalies and a non-causative QF-PCR result (WES-CNV). On request, additional SNV-analysis, restricted to (the) requested gene panel(s) only (with the option of whole exome SNV-analysis afterward) was performed simultaneously (WES-CNV/SNV) or as rapid SNV-re-analysis, following a normal CNV analysis. RESULTS: In total, 415 prenatal samples were included. Following a non-causative QF-PCR result, WES-CNV analysis was initially requested for 74.3% of the chorionic villus (CV) samples and 45% of the amniotic fluid (AF) samples. In case WES-CNV analysis did not reveal a causative aberration, SNV-re-analysis was requested in 41.7% of the CV samples and 17.5% of the AF samples. All initial analyses could be finished within 2 weeks after sampling. For SNV-re-analysis during pregnancy, turn-around-times (TATs) varied between one and 8 days. CONCLUSION: We show a highly efficient all-in-one WES-based strategy, with short TATs, and the option of rapid SNV-re-analysis after a normal CNV result.

Experiences of pregnant women with genome-wide non-invasive prenatal testing in a national screening program.

Pregnant women's perspectives should be included in the dialogue surrounding the expanding offers of non-invasive prenatal testing (NIPT), especially now that technological possibilities are rapidly increasing. This study evaluated women's experiences with the offer of genome-wide (GW) first-tier NIPT in a national screening program. A nationwide pre-and post-test questionnaire was completed by 473 pregnant women choosing between targeted NIPT (trisomies 21, 18 and 13 only) and GW-NIPT (also other findings) within the Dutch TRIDENT-2 study. Measures included satisfaction, reasons for or against choosing GW-NIPT, anxiety, and opinion on the future scope of NIPT. Most respondents (90.4%) were glad to have been offered the choice between GW-NIPT and targeted NIPT; 76.5% chose GW-NIPT. Main reasons to choose GW-NIPT were 'wanting as much information as possible regarding the child's health' (38.6%) and 'to be prepared for everything' (23.8%). Main reasons to choose targeted NIPT were 'avoiding uncertain results/outcomes' (33.7%) and 'not wanting to unnecessarily worry' (32.6%). Nearly all respondents received a low-risk NIPT result (98.7%). No differences were found in anxiety between women choosing GW-NIPT and targeted NIPT. Most respondents were favorable toward future prenatal screening for a range of conditions, including life-threatening disorders, mental disabilities, disorders treatable in pregnancy and severe physical disabilities, regardless of their choice for GW-NIPT or targeted NIPT. In conclusion, women who chose first-tier NIPT were satisfied with the choice between GW-NIPT and targeted NIPT, and most women were favorable toward a broader future screening offer. Our results contribute to the debate concerning the expansion of NIPT.

Clinical impact of additional findings detected by genome-wide non-invasive prenatal testing: Follow-up results of the TRIDENT-2 study.

In the TRIDENT-2 study, all pregnant women in the Netherlands are offered genome-wide non-invasive prenatal testing (GW-NIPT) with a choice of receiving either full screening or screening solely for common trisomies. Previous data showed that GW-NIPT can reliably detect common trisomies in the general obstetric population and that this test can also detect other chromosomal abnormalities (additional findings). However, evidence regarding the clinical impact of screening for additional findings is lacking. Therefore, we present follow-up results of the TRIDENT-2 study to determine this clinical impact based on the laboratory and perinatal outcomes of cases with additional findings. Between April 2017 and April 2019, additional findings were detected in 402/110,739 pregnancies (0.36%). For 358 cases, the origin was proven to be either fetal (n = 79; 22.1%), (assumed) confined placental mosaicism (CPM) (n = 189; 52.8%), or maternal (n = 90; 25.1%). For the remaining 44 (10.9%), the origin of the aberration could not be determined. Most fetal chromosomal aberrations were pathogenic and associated with severe clinical phenotypes (61/79; 77.2%). For CPM cases, occurrence of pre-eclampsia (8.5% [16/189] vs 0.5% [754/159,924]; RR 18.5), and birth weight <2.3rd percentile (13.6% [24/177] vs 2.5% [3,892/155,491]; RR 5.5) were significantly increased compared to the general obstetric population. Of the 90 maternal findings, 12 (13.3%) were malignancies and 32 (35.6%) (mosaic) pathogenic copy number variants, mostly associated with mild or no clinical phenotypes. Data from this large cohort study provide crucial information for deciding if and how to implement GW-NIPT in screening programs. Additionally, these data can inform the challenging interpretation, counseling, and follow-up of additional findings.

Noninvasive Prenatal Test Results Indicative of Maternal Malignancies: A Nationwide Genetic and Clinical Follow-Up Study.

PURPOSE: Noninvasive prenatal testing (NIPT) for fetal aneuploidy screening using cell-free DNA derived from maternal plasma can incidentally raise suspicion for cancer. Diagnostic routing after malignancy suspicious-NIPT faces many challenges. Here, we detail malignancy suspicious-NIPT cases, and describe the clinical characteristics, chromosomal aberrations, and diagnostic routing of the patients with a confirmed malignancy. Clinical lessons can be learned from our experience. METHODS: Patients with NIPT results indicative of a malignancy referred for tumor screening between April 2017 and April 2020 were retrospectively included from a Dutch nationwide NIPT implementation study, TRIDENT-2. NIPT profiles from patients with confirmed malignancies were reviewed, and the pattern of chromosomal aberrations related to tumor type was analyzed. We evaluated the diagnostic contribution of clinical and genetic examinations. RESULTS: Malignancy suspicious-NIPT results were reported in 0.03% after genome-wide NIPT, and malignancies confirmed in 16 patients (16/48, 33.3%). Multiple chromosomal aberrations were seen in 23 of 48 patients with genome-wide NIPT, and a malignancy was confirmed in 16 patients (16/23, 69.6%). After targeted NIPT, 0.005% malignancy suspicious-NIPT results were reported, in 2/3 patients a malignancy was confirmed. Different tumor types and stages were diagnosed, predominantly hematologic malignancies (12/18). NIPT data showed recurrent gains and losses in primary mediastinal B-cell lymphomas and classic Hodgkin lymphomas. Magnetic resonance imaging and computed tomography were most informative in diagnosing the malignancy. CONCLUSION: In 231,896 pregnant women, a low percentage (0.02%) of NIPT results were assessed as indicative of a maternal malignancy. However, when multiple chromosomal aberrations were found, the risk of a confirmed malignancy was considerably high. Referral for extensive oncologic examination is recommended, and may be guided by tumor-specific hallmarks in the NIPT profile.

Liquid biopsy: state of reproductive medicine and beyond.

Liquid biopsy is the process of sampling and analyzing body fluids, which enables non-invasive monitoring of complex biological systems in vivo. Liquid biopsy has myriad applications in health and disease as a wide variety of components, ranging from circulating cells to cell-free nucleic acid molecules, can be analyzed. Here, we review different components of liquid biopsy, survey state-of-the-art, non-invasive methods for detecting those components, demonstrate their clinical applications and discuss ethical considerations. Furthermore, we emphasize the importance of artificial intelligence in analyzing liquid biopsy data with the aim of developing ethically-responsible non-invasive technologies that can enhance individualized healthcare. While previous reviews have mainly focused on cancer, this review primarily highlights applications of liquid biopsy in reproductive medicine.

Non-invasive prenatal diagnosis for translocation carriers-YES please or NO go?

INTRODUCTION: The presence of an unbalanced familial translocation can be reliably assessed in the cytotrophoblast of chorionic villi. However, carriers of a balanced translocation often decline invasive testing. This study aimed to investigate whether an unbalanced translocation can also be diagnosed in cell free DNA by whole-genome non-invasive prenatal screening (NIPS). MATERIAL AND METHODS: Pregnant women carrying a fetus with an unbalanced familial translocation, for whom NIPS as well as microarray data were available, were included in this retrospective assessment. NIPS was performed in the course of the TRIDENT study. RESULTS: In 12 cases, both NIPS and microarray data were available. In 10 of 12 cases the unbalanced translocation was correctly identified by NIPS without prior knowledge on parental translocation. One was missed because the fetal fraction was too low. One was missed because of technical restrictions in calling 16p gains. CONCLUSIONS: This study supports the hypothesis that routine NIPS may be used for prenatal diagnosis of unbalanced inheritance of familial translocations, especially with prior knowledge of the translocation allowing focused examination of the involved chromosomal regions. Our study showed that routine shallow sequencing designed for aneuploidy detection in cell free DNA may be sufficient for higher resolution NIPS, if specialized copy number software is used and if sufficient fetal fraction is present.

TRIDENT-2: National Implementation of Genome-wide Non-invasive Prenatal Testing as a First-Tier Screening Test in the Netherlands.

The Netherlands launched a nationwide implementation study on non-invasive prenatal testing (NIPT) as a first-tier test offered to all pregnant women. This started on April 1, 2017 as the TRIDENT-2 study, licensed by the Dutch Ministry of Health. In the first year, NIPT was performed in 73,239 pregnancies (42% of all pregnancies), 7,239 (4%) chose first-trimester combined testing, and 54% did not participate. The number of trisomies 21 (239, 0.33%), 18 (49, 0.07%), and 13 (55, 0.08%) found in this study is comparable to earlier studies, but the Positive Predictive Values (PPV)-96% for trisomy 21, 98% for trisomy 18, and 53% for trisomy 13-were higher than expected. Findings other than trisomy 21, 18, or 13 were reported on request of the pregnant women; 78% of women chose to have these reported. The number of additional findings was 207 (0.36%); these included other trisomies (101, 0.18%, PPV 6%, many of the remaining 94% of cases are likely confined placental mosaics and possibly clinically significant), structural chromosomal aberrations (95, 0.16%, PPV 32%,) and complex abnormal profiles indicative of maternal malignancies (11, 0.02%, PPV 64%). The implementation of genome-wide NIPT is under debate because the benefits of detecting other fetal chromosomal aberrations must be balanced against the risks of discordant positives, parental anxiety, and a potential increase in (invasive) diagnostic procedures. Our first-year data, including clinical data and laboratory follow-up data, will fuel this debate. Furthermore, we describe how NIPT can successfully be embedded into a national screening program with a single chain for prenatal care including counseling, testing, and follow-up.

Deleterious de novo variants of X-linked ZC4H2 in females cause a variable phenotype with neurogenic arthrogryposis multiplex congenita.

Pathogenic variants in the X-linked gene ZC4H2, which encodes a zinc-finger protein, cause an infrequently described syndromic form of arthrogryposis multiplex congenita (AMC) with central and peripheral nervous system involvement. We present genetic and detailed phenotypic information on 23 newly identified families and simplex cases that include 19 affected females from 18 families and 14 affected males from nine families. Of note, the 15 females with deleterious de novo ZC4H2 variants presented with phenotypes ranging from mild to severe, and their clinical features overlapped with those seen in affected males. By contrast, of the nine carrier females with inherited ZC4H2 missense variants that were deleterious in affected male relatives, four were symptomatic. We also compared clinical phenotypes with previously published cases of both sexes and provide an overview on 48 males and 57 females from 42 families. The spectrum of ZC4H2 defects comprises novel and recurrent mostly inherited missense variants in affected males, and de novo splicing, frameshift, nonsense, and partial ZC4H2 deletions in affected females. Pathogenicity of two newly identified missense variants was further supported by studies in zebrafish. We propose ZC4H2 as a good candidate for early genetic testing of males and females with a clinical suspicion of fetal hypo-/akinesia and/or (neurogenic) AMC.

Origin and clinical relevance of chromosomal aberrations other than the common trisomies detected by genome-wide NIPS: results of the TRIDENT study.

PurposeNoninvasive prenatal screening (NIPS) using cell-free DNA in maternal blood is highly sensitive for detecting fetal trisomies 21, 18, and 13. Using a genome-wide approach, other chromosome anomalies can also be detected. We report on the origin, frequency, and clinical significance of these other chromosome aberrations found in pregnancies at risk for trisomy 21, 18, or 13.MethodsWhole-genome shallow massively parallel sequencing was used and all autosomes were analyzed.ResultsIn 78 of 2,527 cases (3.1%) NIPS was indicative of trisomy 21, 18, or 13, and in 41 (1.6%) of other chromosome aberrations. The latter were of fetal (n = 10), placental (n = 22), maternal (n = 1) or unknown (n = 7). One case lacked cytogenetic follow-up. Nine of the 10 fetal cases were associated with an abnormal phenotype. Thirteen of the 22 (59%) placental aberrations were associated with fetal congenital anomalies and/or poor fetal growth (

Women's Experience with Non-Invasive Prenatal Testing and Emotional Well-being and Satisfaction after Test-Results.

Increasingly, high-risk pregnant women opt for non-invasive prenatal testing (NIPT) instead of invasive diagnostic testing. Since NIPT is less accurate than invasive testing, a normal NIPT result might leave women less reassured. A questionnaire study was performed among pregnant women with elevated risk for fetal aneuploidy based on first-trimester combined test (risk ≥1:200) or medical history, who were offered NIPT in the nationwide Dutch TRIDENT study. Pre- and post-test questionnaires (n = 682) included measures on: experiences with NIPT procedure, feelings of reassurance, anxiety (State-Trait Anxiety Inventory, STAI), child-related anxiety (PRAQ-R), and satisfaction. The majority (96.1%) were glad to have been offered NIPT. Most (68.5%) perceived the waiting time for NIPT results (mean: 15 days, range 5-32) as (much) too long. Most women with a normal NIPT result felt reassured (80.9%) or somewhat reassured (15.7%). Levels of anxiety and child-related anxiety were significantly lower after receiving a normal NIPT result as compared to the moment of intake (p < 0.001). Women with inadequate health literacy or a medical history (e.g. previous child with trisomy) experienced significantly higher post-test-result anxiety (Mean (M) STAI = 31.6 and 30.0, respectively) compared to those with adequate health literacy (M = 28.6) and no medical history (M = 28.6), indicating these women might benefit from extra information and/or guidance when communicating NIPT test-results. Introducing NIPT as an alternative to invasive testing, led to an offer that satisfied and largely reassured high-risk pregnant women.

Trial by Dutch laboratories for evaluation of non-invasive prenatal testing. Part II-women's perspectives.

OBJECTIVE: To evaluate preferences and decision-making among high-risk pregnant women offered a choice between Non-Invasive Prenatal Testing (NIPT), invasive testing or no further testing. METHODS: Nationwide implementation study (TRIDENT) offering NIPT as contingent screening test for women at increased risk for fetal aneuploidy based on first-trimester combined testing (>1:200) or medical history. A questionnaire was completed after counseling assessing knowledge, attitudes and participation following the Multidimensional Measure of Informed Choice. RESULTS: A total of 1091/1253 (87%) women completed the questionnaire. Of these, 1053 (96.5%) underwent NIPT, 37 (3.4%) invasive testing and 1 (0.1%) declined testing. 91.7% preferred NIPT because of test safety. Overall, 77.9% made an informed choice, 89.8% had sufficient knowledge and 90.5% had positive attitudes towards NIPT. Women with intermediate (odds ratio (OR) = 3.51[1.70-7.22], p < 0.001) or high educational level (OR = 4.36[2.22-8.54], p < 0.001) and women with adequate health literacy (OR = 2.60[1.36-4.95], p = 0.004) were more likely to make an informed choice. Informed choice was associated with less decisional conflict and less anxiety (p < 0.001). Intention to terminate the pregnancy for Down syndrome was higher among women undergoing invasive testing (86.5%) compared to those undergoing NIPT (58.4%) (p < 0.001). CONCLUSIONS: The majority of women had sufficient knowledge and made an informed choice. Continuous attention for counseling is required, especially for low-educated and less health-literate women. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

Trial by Dutch laboratories for evaluation of non-invasive prenatal testing. Part I-clinical impact.

OBJECTIVE: To evaluate the clinical impact of nationwide implementation of genome-wide non-invasive prenatal testing (NIPT) in pregnancies at increased risk for fetal trisomies 21, 18 and 13 (TRIDENT study). METHOD: Women with elevated risk based on first trimester combined testing (FCT ≥ 1:200) or medical history, not advanced maternal age alone, were offered NIPT as contingent screening test, performed by Dutch University Medical laboratories. We analyzed uptake, test performance, redraw/failure rate, turn-around time and pregnancy outcome. RESULTS: Between 1 April and 1 September 2014, 1413/23 232 (6%) women received a high-risk FCT result. Of these, 1211 (85.7%) chose NIPT. One hundred seventy-nine women had NIPT based on medical history. In total, 1386/1390 (99.7%) women received a result, 6 (0.4%) after redraw. Mean turn-around time was 14 days. Follow-up was available in 1376 (99.0%) pregnancies. NIPT correctly predicted 37/38 (97.4%) trisomies 21, 18 or 13 (29/30, 4/4 and 4/4 respectively); 5/1376 (0.4%) cases proved to be false positives: trisomies 21 (n = 2), 18 (n = 1) and 13 (n = 2). Estimated reduction in invasive testing was 62%. CONCLUSION: Introduction of NIPT in the Dutch National healthcare-funded Prenatal Screening Program resulted in high uptake and a vast reduction of invasive testing. Our study supports offering NIPT to pregnant women at increased risk for fetal trisomy. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

Cell-Free RNA Is a Reliable Fetoplacental Marker in Noninvasive Fetal Sex Determination.

BACKGROUND: Noninvasive genetic tests that use cell-free fetal DNA (cffDNA) are used increasingly in prenatal care. A low amount of cffDNA can have detrimental effects on the reliability of these tests. A marker to confirm the presence of fetal nucleic acids is therefore required that is universally applicable and easy to incorporate. METHODS: We developed a novel multiplex, single-tube, noninvasive fetal sex determination assay by combining amplification of AMELY cffDNA with one-step reverse transcription (RT)-PCR of trophoblast-derived cell-free RNA (cfRNA), which functions as a sex-independent fetoplacental marker. We tested plasma samples from 75 pregnant women in duplicate in a blinded fashion. The fetus was considered to be male in the case of a positive result for AMELY and cfRNA amplification in both RT-PCRs. The fetus was considered to be female in the case of negative AMELY and positive cfRNA result in both RT-PCRs. In other cases, the test was repeated. We compared the results with invasive prenatal testing and pregnancy outcomes. RESULTS: The AMELY cffDNA amplification and cfRNA result was unambiguous and identical in duplicate in 71 of 75 plasma samples (95%). Four samples (5%) required an extra replicate because of an absent fetoplacental marker. Thereafter, fetal sex was correctly determined in all 75 plasma samples. CONCLUSIONS: Amplification of trophoblast-derived cfRNA is a reliable marker for the confirmation of the presence of fetoplacentally derived nucleic acids in noninvasive fetal sex determination.

Absence of heterozygosity due to template switching during replicative rearrangements.

We investigated complex genomic rearrangements (CGRs) consisting of triplication copy-number variants (CNVs) that were accompanied by extended regions of copy-number-neutral absence of heterozygosity (AOH) in subjects with multiple congenital abnormalities. Molecular analyses provided observational evidence that in humans, post-zygotically generated CGRs can lead to regional uniparental disomy (UPD) due to template switches between homologs versus sister chromatids by using microhomology to prime DNA replication-a prediction of the replicative repair model, MMBIR. Our findings suggest that replication-based mechanisms might underlie the formation of diverse types of genomic alterations (CGRs and AOH) implicated in constitutional disorders.