Expanded Non-invasive Prenatal Testing (NIPT) : Can the Child's Right to an Open Future Help Set the Scope?

Expanded non-invasive prenatal testing (NIPT) has provoked ethical concerns about its justifiable scope. In this paper, we evaluate the role of the child's right to an open future in setting the scope of NIPT. This 'open future principle' has been cited in arguments both limiting and expanding parental freedoms. This moral right holds that adult autonomy rights which children cannot yet exercise should nonetheless be protected until they can. Its purpose is to protect the future autonomy of the child as a future adult. Several authors have extended this rationale from child to fetus. However, the right was not anticipated to apply to the fetus, a non-legal entity in many jurisdictions. The aim of this paper is to reconsider whether this principle is useful to help deliberate the scope of NIPT. We find that extending the open future principle to delineate the scope of NIPT is theoretically flawed. We contend that in the prenatal context its value primarily lies with counselling for prenatal screening where it can be used to encourage parents' reflection on the implications of knowing for the sake of knowing on their future children and their relationship with them.

Balancing Needs and Autonomy: The Involvement of Pregnant Women's Partners in Decisions About cfDNA

Cell-free fetal DNA (cfDNA) screening is used to identify the presence of fetal genetic variants early in pregnancy. Patients' informed decision-making is central to the success of this new screen in clinical practice. Although research has focused on pregnant women's decision-making, little is known about partners' role and preferences as a member of the decision-making dyad. Using a grounded theory approach, this study analyzed 23 in-depth interviews to examine partners' perspectives about cfDNA screening and preferences with respect to their role in the decision-making process. Participants wished to be actively involved in testing decisions. They articulated a distinct set of needs and preferences in the decision-making process. Such involvement was hindered by several biological and logistical barriers. This study demonstrates the need to develop mechanisms that foster informed decision-making for cfDNA screening and related new reproductive genetic technologies that focus on not just the pregnant woman but also the decision-making dyad that includes her partner as well.

Could Digital PCR Be an Alternative as a Non-Invasive Prenatal Test for Trisomy 21: A Proof of Concept Study

Objective

NIPT for fetal aneuploidy by digital PCR has been hampered by the large number of PCR reactions needed to meet statistical requirements, preventing clinical application. Here, we designed an octoplex droplet digital PCR (ddPCR) assay which allows increasing the number of available targets and thus overcomes statistical obstacles.

Method

After technical optimization of the multiplex PCR on mixtures of trisomic and euploid DNA, we performed a validation study on samples of plasma DNA from 213 pregnant women. Molecular counting of circulating cell-free DNA was performed using a mix of hydrolysis probes targeting chromosome 21 and a reference chromosome.

Results

The results of our validation experiments showed that ddPCR detected trisomy 21 even when the sample’s trisomic DNA content is as low as 5%. In a validation study of plasma samples from 213 pregnant women, ddPCR discriminated clearly between the trisomy 21 and the euploidy groups.

Conclusion

Our results demonstrate that digital PCR can meet the requirements for non-invasive prenatal testing of trisomy 21. This approach is technically simple, relatively cheap, easy to implement in a diagnostic setting and compatible with ethical concerns regarding access to nucleotide sequence information. These advantages make it a potential technique of choice for population-wide screening for trisomy 21 in pregnant women.

Two kinds of common prenatal screening tests for Down's syndrome: a systematic review and meta-analysis

As the chromosomal examination of foetal cells for the prenatal diagnosis of Down's syndrome (DS) carries a risk of inducing miscarriage, serum screening tests are commonly used before invasive procedures. In this study, a total of 374 records from PubMed, EMBASE, and the ISI Science Citation Index databases were reviewed. As a result of duplication, insufficient data, and inappropriate article types, 18 independent articles containing 183,998 samples were used in the final systematic review and meta-analysis of the diagnostic performance of the serum triple screening test (STS) and the integrated screening test (INS). Data extracted from the selected studies were statistically analysed, and the presence of heterogeneity and publication bias was assessed using specific software. The overall sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the area under the curve for the STS were 0.77 (95% confidence interval = 0.73-0.81), 0.94 (0.94-0.94), 9.78 (6.87-13.93), 0.26 (0.22-0.31), 44.72 (30.77-65.01), and 0.9064, respectively. For the INS, these values were 0.93 (0.90-0.95), 0.93 (0.93-0.93), 22.38 (12.47-40.14), 0.08 (0.05-0.11), 289.81 (169.08-496.76), and 0.9781, respectively. These results indicate that the INS exhibits better diagnostic value for DS. However, further research is needed to identify other biomarkers to improve prenatal screening tests.

Changing to NIPT as a first-tier screening test and future perspectives: opinions of health professionals

OBJECTIVE

The aim of this study was to investigate health professionals' opinions toward offering noninvasive prenatal testing (NIPT) as first-tier screening test regardless of pregnant women's risk, and toward a potential broader range of disorders.

METHODS

A questionnaire completed by obstetric health professionals (n = 240) after an in-service NIPT training in the West and North of the Netherlands.

RESULTS

The majority (72%) of respondents favored replacing first-trimester combined test (FCT) by NIPT, although 43% preferred to maintain nuchal translucency measurement. Many respondents believed that replacing FCT by NIPT would only have advantages (57%), would lead to more pregnant women opting for prenatal testing (69%), and would simplify counseling (47%). Differences in attitudes toward counseling between health professionals were observed. When considering NIPT to screen for broader range of disorders, the majority (92%) thought that this should include disorders characterized by neonatal death, whereas 52% of the respondents favored testing for fetomaternal risk factors. Overall, 46% thought screening should be offered as a fixed list of disorders.

CONCLUSION

Most health professionals favor NIPT instead of FCT but prefer to maintain nuchal translucency measurement. If NIPT becomes available as a first-tier screening test, attention remains necessary to ensure that pregnant women make well-informed decisions in line with the aim of prenatal screening.

Advantages and Disadvantages of Different Implementation Strategies of Non-Invasive Prenatal Testing in Down Syndrome Screening Programmes

BACKGROUND

Implementation of non-invasive prenatal testing (NIPT) in Down syndrome screening programmes requires health policy decisions about its combination with other tests and its timing in pregnancy.

AIM

Our aim was to aid health policy decision makers by conducting a quantitative analysis of different NIPT implementation strategies.

METHODS

Decision trees were created to illustrate all plausible alternatives in a theoretical cohort of 100,000 pregnant women in five screening programmes: classical screening by the first-trimester combined test (FCT), pre-selection of high-risk women prior to NIPT by the FCT, NIPT as the first screening test at 10 weeks and at 13 weeks, and the simultaneous conductance of NIPT and the FCT.

RESULTS

Pre-selection by FCT prior to NIPT reduces the number of amniocenteses to a minimum because of a reduction of false-positive NIPT results. If NIPT is the first screening test, it detects almost all fetal Down syndrome cases. NIPT at 10 weeks reassures women early in pregnancy, while NIPT at 13 weeks prevents unnecessary tests due to spontaneous miscarriages and allows for immediate confirmation by amniocentesis.

CONCLUSION

Every implementation strategy has its advantages and disadvantages. The most favourable implementation strategy may be NIPT as the first screening test at 13 weeks, offering the most accurate screening test for Down syndrome, when the risk for spontaneous miscarriage has declined remarkably and timely confirmation by amniocentesis can be performed.

What women want: lead considerations for current and future applications of noninvasive prenatal testing in prenatal care

BACKGROUND

Noninvasive prenatal testing (NIPT) will change the delivery of prenatal care for all women, including those considered low risk for fetal chromosomal abnormalities. This study investigated pregnant women's attitudes, informational needs, and decision-making preferences with respect to current and future applications of NIPT.

METHODS

A survey instrument was used to identify aspects of the decision-making process for NIPT among low-risk and high-risk populations.

RESULTS

Both low-risk and high-risk women (n = 334) expressed interest in incorporating NIPT as a screening test into their prenatal care. Information specific to NIPT's detection rate (86%), indications (77%), and performance in comparison with conventional screens and diagnostic tests (63%) were identified as lead factors when considering its use. The future availability of NIPT as a diagnostic test increased women's willingness to undergo testing for fetal aneuploidy, cancer susceptibility, and childhood-onset and adult-onset diseases. Despite its noninvasive aspects, participants expressed the need for a formal informed consent process (71%) to take place before testing.

CONCLUSIONS

This study demonstrates that NIPT will introduce new challenges for pregnant women and their health care practitioners who will be charged with supporting informed decision making about its use. It is critical that obstetric professionals are prepared to facilitate a patient-centered decision-making process as its clinical application rapidly changes.

It's More Than a Blood Test: Patients' Perspectives on Noninvasive Prenatal Testing

Noninvasive prenatal testing (NIPT) offers pregnant women a new risk assessment tool for fetal aneuploidy that is superior to conventional screening tests. We conducted focus groups with women who were currently pregnant or had recently delivered in the past year to characterize their perspectives about NIPT and to explore factors they would consider during decision making about its use. Women identified accuracy, early timing, testing ease, and determination of fetal sex as advantages of NIPT over other screens, and the noninvasive method of NIPT as an advantage over diagnostic tests. False positive and false negative results, anxiety, cost and insurance coverage were seen as disadvantages of NIPT. Women who do not want fetal aneuploidy information most likely will not undergo NIPT, despite its advantages over other screening tests. However, given its advantages, the decision to have NIPT is straightforward for women who want genetic information about the fetus. Women emphasized the need to make autonomous, private, and informed choices about NIPT, as they would with any prenatal genetic testing option. These perspectives may guide clinicians to conduct effective and clinically relevant counseling with pregnant women who consider utilizing this new genetic technology.

Preimplantation genetic diagnosis for a Chinese family with autosomal recessive Meckel-Gruber syndrome type 3 (MKS3)

Meckel-Gruber syndrome type 3 is an autosomal recessive genetic defect caused by mutations in TMEM67 gene. In our previous study, we have identified a homozygous TMEM67 mutation in a Chinese family exhibiting clinical characteristics of MKS3, which provided a ground for further PGD procedure. Here we report the development and the first clinical application of the PGD for this MKS3 family. Molecular analysis protocol for clinical PGD procedure was established using 50 single cells in pre-clinical set-up. After whole genomic amplification by multiple displacement amplification with the DNA from single cells, three techniques were applied simultaneously to increase the accuracy and reliability of genetic diagnosis in single blastomere, including real-time PCR with Taq Man-MGB probe, haplotype analysis with polymorphic STR markers and Sanger sequencing. In the clinical PGD cycle, nine embryos at cleavage-stage were biopsied and subjected to genetic diagnosis. Two embryos diagnosed as free of TMEM67 mutation were transferred and one achieving normal pregnancy. Non-invasive prenatal assessment of trisomy 13, 18 and 21 by multiplex DNA sequencing at 18 weeks’ gestation excluded the aneuploidy of the analyzed chromosomes. A healthy boy was delivered by cesarean section at 39 weeks’ gestation. DNA sequencing from his cord blood confirmed the result of genetic analysis in the PGD cycle. The protocol developed in this study was proved to be rapid and safe for the detection of monogenic mutations in clinical PGD cycle.

A new era in prenatal testing: are we prepared?

Prenatal care and the practice of prenatal genetic testing are about to be changed fundamentally. Due to several ground-breaking technological developments prenatal screening and diagnosis (PND) will soon be offered earlier in gestation, with less procedure-related risks and for a profoundly enlarged variety of targets. In this paper it is argued that the existing normative framework for prenatal screening and diagnosis cannot answer adequately to these new developments. In concentrating on issues of informed consent and the reproductive autonomy of the pregnant women the ethical debate misses problems related to the clinical pathway as a whole and to implicit normative attributions to clinical actions or the function of health care professionals. If, however, ethical debate would focus on the clinical context and on the ends of PND to a larger extent, it would be able to provide a more comprehensive analysis of the ethical challenges especially of the new technologies in order to be more adequately prepared for their implementation.

Noninvasive detection of fetal trisomy 21: systematic review and report of quality and outcomes of diagnostic accuracy studies performed between 1997 and 2012

BACKGROUND

Research on noninvasive prenatal testing (NIPT) of fetal trisomy 21 is developing fast. Commercial tests have become available. To provide an up-to-date overview of NIPT of trisomy 21, an evaluation of the methodological quality and outcomes of diagnostic accuracy studies was made.

METHODS

We undertook a systematic review of the literature published between 1997 and 2012 after searching PubMed, using MeSH terms 'RNA', 'DNA' and 'Down Syndrome' in combination with 'cell-free fetal (cff) RNA', 'cffDNA', 'trisomy 21' and 'noninvasive prenatal diagnosis' and searching reference lists of reported literature. From 79 abstracts, 16 studies were included as they evaluated the diagnostic accuracy of a molecular technique for NIPT of trisomy 21, and the test sensitivity and specificity were reported. Meta-analysis could not be performed due to the use of six different molecular techniques and different cutoff points. Diagnostic parameters were derived or calculated, and possible bias and applicability were evaluated utilizing the revised tool for Quality Assessment of Diagnostic Accuracy (QUADAS-2).

RESULTS

Seven of the included studies were recently published in large cohort studies that examined massively parallel sequencing (MPS), with or without pre-selection of chromosomes, and reported sensitivities between 98.58% [95% confidence interval (CI) 95.9-99.5%] and 100% (95% CI 96-100%) and specificities between 97.95% (95% CI 94.1-99.3%) and 100% (95% CI 99.1-100%). None of these seven large studies had an overall low risk of bias and low concerns regarding applicability. MPS with or without pre-selection of chromosomes exhibits an excellent negative predictive value (100%) in conditions with disease odds from 1:1500 to 1:200. However, positive predictive values were lower, even in high-risk pregnancies (19.7-100%). The other nine cohort studies were too small to give precise estimates (number of trisomy 21 cases: ≤25) and were not included in the discussion.

CONCLUSIONS

NIPT of trisomy 21 by MPS with or without pre-selection of chromosomes is promising and likely to replace the prenatal serum screening test that is currently combined with nuchal translucency measurement in the first trimester of pregnancy. Before NIPT can be introduced as a screening test in a social insurance health-care system, more evidence is needed from large prospective diagnostic accuracy studies in first trimester pregnancies. Moreover, we believe further assessment, of whether NIPT can be provided in a cost-effective, timely and equitable manner for every pregnant woman, is required.

Nichtinvasive molekulargenetische Methoden in der pränatalen Diagnostik

Seit vielen Jahren wird an der Entwicklung nichtinvasiver pränataler Untersuchungen gearbeitet, um die Risiken für den Fetus bei der traditionellen Amniozentese oder Choriozottenbiopsie zu umgehen. Bis vor Kurzem waren die meisten Ansätze extrem aufwendig und nur auf ausgewählte Fragestellungen limitiert, sodass sie nicht über einen „Proof-of-principle-Status“ hinauskamen. Dies hat sich durch Einführung neuer Sequenzierverfahren grundlegend geändert, weil erste Studien belegten, dass fetale Aneuploidien aus mütterlicher Plasma-DNA korrekt identifiziert werden können. Darüber hinaus erlauben diese Techniken auch den Mutationsstatus des Fetus zu erheben, sodass sich einerseits in der pränatalen Diagnostik ganz neue Möglichkeiten ergeben, die andererseits aber auch mit erheblichen ethischen Herausforderungen verbunden sind. In dieser Übersicht wird die Entwicklung zu diesen neuen Verfahren dargestellt.