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Objectives: Determine the incremental diagnostic yield of prenatal exome sequencing (pES) over chromosome microarray (CMA) or G-banding karyotype in fetuses with central nervous system (CNS) abnormalities., Methods: Data were collected via electronic searches from January 2010 to April 2022 in MEDLINE, Cochrane, Web of Science and EMBASE. The NHS England prenatal exome cohort was also included. Incremental yield was calculated as a pooled value using a random-effects model., Results: Thirty studies were included (n = 1583 cases). The incremental yield with pES for any CNS anomaly was 32% [95%CI 27%-36%; I 2  = 72%]. Subgroup analysis revealed apparent incremental yields in; (a) isolated CNS anomalies; 27% [95%CI 19%-34%; I 2  = 74%]; (b) single CNS anomaly; 16% [95% CI 10%-23%; I 2  = 41%]; (c) more than one CNS anomaly; 31% [95% Cl 21%-40%; I 2  = 56%]; and (d) the anatomical subtype with the most optimal yield was Type 1 malformation of cortical development, related to abnormal cell proliferation or apoptosis, incorporating microcephalies, megalencephalies and dysplasia; 40% (22%-57%; I 2  = 68%). The commonest syndromes in isolated cases were Lissencephaly 3 and X-linked hydrocephalus., Conclusions: Prenatal exome sequencing provides a high incremental diagnostic yield in fetuses with CNS abnormalities with optimal yields in cases with multiple CNS anomalies, particularly those affecting the midline, posterior fossa and cortex., (© 2023 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd.)

Objectives: To develop a flexible droplet digital PCR (ddPCR) workflow to perform non-invasive prenatal diagnosis via relative mutation dosage (RMD) for maternal pathogenic variants with a range of inheritance patterns, and to compare the accuracy of multiple analytical approaches., Methods: Cell free DNA (cfDNA) was tested from 124 archived maternal plasma samples: 88 cases for sickle cell disease and 36 for rare Mendelian conditions. Three analytical methods were compared: sequential probability ratio testing (SPRT), Bayesian and z-score analyses., Results: The SPRT, Bayesian and z-score analyses performed similarly well with correct prediction rates of 96%, 97% and 98%, respectively. However, there were high rates of inconclusive results for each cohort, particularly for z-score analysis which was 31% overall. Two samples were incorrectly classified by all three analytical methods; a false negative result predicted for a fetus affected with sickle cell disease and a false positive result predicting the presence of an X-linked IDS variant in an unaffected fetus., Conclusions: ddPCR can be applied to RMD for diverse conditions and inheritance patterns, but all methods carry a small risk of erroneous results. Further evaluation is required both to reduce the rate of inconclusive results and explore discordant results in more detail., (© 2023 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd.)

The research and clinical use of genome-wide sequencing for prenatal diagnosis of fetuses at risk for genetic disorders have rapidly increased in recent years. Current data indicate that the diagnostic rate is comparable and for certain indications higher than that of standard testing by karyotype and chromosomal microarray. Responsible clinical implementation and diagnostic use of prenatal sequencing depends on standardized laboratory practices and detailed pre-test and post-test counseling. This Updated Position Statement on behalf of the International Society for Prenatal Diagnosis recommends best practices for the clinical use of prenatal exome and genome sequencing from an international perspective. We include several new points for consideration by researchers and clinical service and laboratory providers., (© 2022 John Wiley & Sons Ltd.)

Non-invasive prenatal testing (NIPT) based on analysis of cell free DNA circulating in the maternal plasma has been available clinically to screen for chromosomal abnormalities since 2011. There is significant evidence to suggest that NIPT has revolutionised prenatal screening for the common trisomies 13, 18, and 21. However, the evidence in favour of its extended use to screen for conditions other than these trisomies remains a topic of debate with no national or international organisation supporting clinical implementation for these indications. In the debate presented here - "Expanded NIPT that includes conditions other than trisomies 13, 18, and 21 should be offered" - we will see the pros and cons of screening for a wider range of chromosomal problems. The discussion presented swung the vote from 65% in favour and 35% against before the arguments were voiced to 41% in favour and 59% against. This significant swing in the vote indicates that the majority of our community feel more evidence is required before clinical implementation of extended NIPT., (© 2021 John Wiley & Sons Ltd.)

Background: Tests in pregnancy such as chromosomal microarray analysis and exome sequencing are increasing diagnostic yield for fetal structural anomalies, but have greater potential to result in uncertain findings. This systematic review investigated the experiences of prospective parents about receiving uncertain results from these tests., Methods: A systematic search of three electronic databases was conducted. Data extraction was performed for studies that met the eligibility and quality criteria. Results were synthesised following the principles of thematic analysis., Results: Fourteen studies (10 qualitative, 4 quantitative) were included. Findings were grouped into three overarching themes. Sources of uncertainty included the testing procedure, the diagnosis and prognosis, and health professionals' own uncertainty. The clinical impact of the uncertainty included parents struggling to make clinical decisions with the information available, the emotional impact included decisional-regret, shock, worry and feeling overwhelmed. To manage the uncertainty, parents sought support from healthcare professionals, friends, family, the internet and other parents as well as remaining hopeful., Conclusions: Prospective parents experience a myriad of uncertainties in the prenatal setting, which must be handled sensitively. Future research should explore optimal ways of managing uncertainty to minimise harm. Recommendations are made for discussing uncertainty during pre- and post-test counseling., (© 2020 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd.)

Unexpected fetal abnormalities detected through ultrasound scanning in pregnancy may have a monogenic aetiology but are difficult to diagnose. Next generation sequencing now enables us to sequence fetal exomes, providing increased resolution and broader diagnostic capability compared to traditional cytogenetic prenatal tests, improving the yield and accuracy of diagnoses and allowing better counselling for expectant parents. Here we review published studies of exome sequencing (ES) for prenatal diagnosis over the last 5 years and address important questions for its clinical implementation, including clinical utility, which groups benefit most, and practical and ethical challenges for interpreting and reporting results. We observe that fetal ES substantially improves diagnostic yield relative to cytogenetic techniques. However, diagnostic rates vary widely between studies, largely attributable to differences in case selection. Recently several large studies report variations in diagnostic yield between phenotypic groups, with fetuses with multisystem abnormalities most likely to receive a diagnosis from fetal ES. Challenges for prenatal ES include the limitations of ultrasound-based fetal phenotyping, the need for rapid return of results in pregnancy, and technical limitations compared to whole genome sequencing. We also consider ethical issues around potential secondary findings and variants of uncertain significance and the complex counselling needs these present. Prenatal ES is a valuable tool to diagnose fetal abnormalities and, as it is implemented in the clinic, more large-scale research will serve to further delineate its clinical utility, as well as generating new knowledge about fetal phenotypes and informing guidelines for case selection, reporting results and genetic counselling., (Copyright © 2019. Published by Elsevier Masson SAS.)

Purpose: Unexpected fetal abnormalities occur in 2-5% of pregnancies. While traditional cytogenetic and microarray approaches achieve diagnosis in around 40% of cases, lack of diagnosis in others impedes parental counseling, informed decision making, and pregnancy management. Postnatally exome sequencing yields high diagnostic rates, but relies on careful phenotyping to interpret genotype results. Here we used a multidisciplinary approach to explore the utility of rapid fetal exome sequencing for prenatal diagnosis using skeletal dysplasias as an exemplar., Methods: Parents in pregnancies undergoing invasive testing because of sonographic fetal abnormalities, where multidisciplinary review considered skeletal dysplasia a likely etiology, were consented for exome trio sequencing (both parents and fetus). Variant interpretation focused on a virtual panel of 240 genes known to cause skeletal dysplasias., Results: Definitive molecular diagnosis was made in 13/16 (81%) cases. In some cases, fetal ultrasound findings alone were of sufficient severity for parents to opt for termination. In others, molecular diagnosis informed accurate prediction of outcome, improved parental counseling, and enabled parents to terminate or continue the pregnancy with certainty., Conclusion: Trio sequencing with expert multidisciplinary review for case selection and data interpretation yields timely, high diagnostic rates in fetuses presenting with unexpected skeletal abnormalities. This improves parental counseling and pregnancy management.

Emerging genomic technologies, largely based around next generation sequencing (NGS), are offering new promise for safer prenatal genetic diagnosis. These innovative approaches will improve screening for fetal aneuploidy, allow definitive non-invasive prenatal diagnosis (NIPD) of single gene disorders at an early gestational stage without the need for invasive testing, and improve our ability to detect monogenic disorders as the aetiology of fetal abnormalities. This presents clinicians and scientists with novel challenges as well as opportunities. In addition, the transformation of prenatal genetic testing arising from the introduction of whole genome, exome and targeted NGS produces unprecedented volumes of data requiring complex analysis and interpretation. Now translating these technologies to the clinic has become the goal of clinical genomics, transforming modern healthcare and personalized medicine. The achievement of this goal requires the most progressive technological tools for rapid high-throughput data generation at an affordable cost. Furthermore, as larger proportions of patients with genetic disease are identified we must be ready to offer appropriate genetic counselling to families and potential parents. In addition, the identification of novel treatment targets will continue to be explored, which is likely to introduce ethical considerations, particularly if genome editing techniques are included in these targeted treatments and transferred into mainstream personalized healthcare. Here we review the impact of NGS technology to analyse cell-free DNA (cfDNA) in maternal plasma to deliver NIPD for monogenic disorders and allow more comprehensive investigation of the abnormal fetus through the use of exome sequencing., (Copyright © 2017. Published by Elsevier Ltd.)

Non-invasive prenatal testing (NIPT), based on analysis of cell-free foetal DNA, is rapidly becoming a preferred method to screen for chromosomal aneuploidy with the technology now available in over 90 countries. This review provides an up-to-date discussion of the key clinical, social and ethical implications associated with this revolutionary technology. Stakeholders are positive about a test that is highly accurate, safe, can be perfomed early in pregnancy, identifies affected pregnancies that might otherwise have been missed and reduces the need for invasive testing. Nevertheless, professional societies currently recommend it as an advanced screening test due to the low false positive rate (FPR). Despite the practical and psychological benefits, a number of concerns have been raised which warrant attention. These include the potential for routinisation of testing and subsequent impact on informed decision-making, an "easy" blood test inadvertently contributing to women feeling pressured to take the test, fears NIPT will lead to less tolerance and support for those living with Down syndrome and the heightened expectation of having "perfect babies". These issues can be addressed to some extent through clinician education, patient information and establishing national and international consensus in the development of comprehensive and regularly updated guidelines. As the number of conditions we are able to test for non-invasively expands it will be increasingly important to ensure pre-test counselling can be delivered effectively supported by knowledgeable healthcare professionals.

Prenatal genetic diagnosis provides information for pregnancy and perinatal decision-making and management. In several small series, prenatal whole exome sequencing (WES) approaches have identified genetic diagnoses when conventional tests (karyotype and microarray) were not diagnostic. Here, we review published prenatal WES studies and recent conference abstracts. Thirty-one studies were identified, with diagnostic rates in series of five or more fetuses varying between 6.2% and 80%. Differences in inclusion criteria and trio versus singleton approaches to sequencing largely account for the wide range of diagnostic rates. The data suggest that diagnostic yields will be greater in fetuses with multiple anomalies or in cases preselected following genetic review. Beyond its ability to improve diagnostic rates, we explore the potential of WES to improve understanding of prenatal presentations of genetic disorders and lethal fetal syndromes. We discuss prenatal phenotyping limitations, counselling challenges regarding variants of uncertain significance, incidental and secondary findings, and technical problems in WES. We review the practical, ethical, social and economic issues that must be considered before prenatal WES could become part of routine testing. Finally, we reflect upon the potential future of prenatal genetic diagnosis, including a move towards whole genome sequencing and non-invasive whole exome and whole genome testing. © 2017 John Wiley & Sons, Ltd., (© 2017 John Wiley & Sons, Ltd.)

Background: Non-invasive prenatal diagnosis (NIPD) for sickle-cell disorder (SCD) is moving closer to implementation and studies considering stakeholder preferences are required to underpin strategies for offering NIPD in clinical practice., Objective: Determine service user and provider preferences for key attributes of prenatal diagnostic tests for SCD and examine views on NIPD., Method: A questionnaire that includes a discrete choice experiment was used to determine the preferences of service users and providers for prenatal tests that varied across three attributes: accuracy, time of test and risk of miscarriage., Results: Adults who were carriers of SCD or affected with the condition (N=67) were recruited from haemoglobinopathy clinics at two maternity units. Health professionals, predominately midwives, who offer antenatal care (N=62) were recruited from one maternity unit. No miscarriage risk was a key driver of decision making for both service users and providers. Service providers placed greater emphasis on accuracy than service users. Current uptake of invasive tests was 63%, whilst predicted uptake of NIPD was 93.8%. Many service users (55.4%) and providers (52.5%) think pressure to have prenatal testing will increase when NIPD for SCD becomes available., Conclusions: There are clear differences between service users and health professionals' preferences for prenatal tests for sickle-cell disorder. The safety of NIPD is welcomed by parents and uptake is likely to be high. To promote informed choice, pretest counselling should be balanced and not exclusively focused on test safety. Counselling strategies that are sensitive to feelings of pressure to test will be essential., (© 2017 The Authors Health Expectations Published by John Wiley & Sons Ltd.)

Introduction: Invasive prenatal diagnosis (IPD) has long been used to prenatally diagnose Down syndrome (DS), but it is associated with a small risk of miscarriage. Noninvasive prenatal testing (NIPT) is a highly sensitive screening test using cell-free DNA in maternal blood for detection of DS without the risk of miscarriage, but it confers a small risk of false-positive and false-negative results. The implementation of these procedures into clinical practice requires an understanding of stakeholder preferences., Methods: A total of 69 health professionals (HPs) and 301 women took part in a discrete choice experiment (DCE) in which preferences for four prenatal test attributes - accuracy, time of results, risk of miscarriage and amount of information provided - were assessed. Conditional logit regression was used to analyse the data. Data on demographics and ranked preferences for test attributes was collected, and a direct choice question regarding NIPT, IPD or neither test was posed to participants., Results: The women showed a preference for test safety, whereas HPs prioritised test accuracy above all other attributes. When offered a direct choice of NIPT, IPD or neither test, women aged 35 years and older, those with previous miscarriage or who knew a child with DS were more likely to choose NIPT. Chinese women preferred NIPT, whereas Indian women preferred IPD., Conclusion: Our data highlights the need for patient-specific counselling, taking into account previous experiences and cultural factors. Since women and HPs prioritise different test attributes, it is essential that HPs recognise these differences in order to provide non-biased counselling., (Copyright: © Singapore Medical Association)

Background: The availability of non-invasive prenatal testing (NIPT) for aneuploidies is expanding rapidly throughout the world. Training health professionals to offer NIPT in a way that supports informed choice is essential for implementation. The aim of this study was to develop and evaluate a training package for health professionals to support the introduction of NIPT into clinical practice., Methods: Training on NIPT was offered to health professionals, primarily midwives, involved in Down syndrome screening and testing in eight hospitals located in England and Scotland as part of a research study evaluating the implementation of NIPT in the UK National Health Service. Training was evaluated using a mixed methods approach that included quantitative questionnaires at three time points and post-training qualitative interviews. The questionnaires measured confidence, self-perceived knowledge and actual knowledge about NIPT for Down syndrome. Interviews explored opinions about the training and experiences of offering NIPT., Results: The training provided to the health professionals was found to positively impact on their confidence in discussing NIPT with women in their clinic, and both their perceived and actual knowledge and understanding of NIPT was improved. Knowledge remained weak in four areas; cell-free fetal DNA levels increase with gestation; turnaround time for NIPT results; cell-free fetal DNA is placental in origin; and NIPT false positive rate., Conclusions: Training materials, including a lesson plan, PowerPoint presentation and written factsheet on NIPT, have been developed and evaluated for use in educating midwives and supporting the introduction of NIPT. Implementation of training should include a greater focus on the areas where knowledge remained low. Some groups of midwives will need additional training or support to optimise their confidence in discussing NIPT with women.

Objective: To explore women's attitudes towards non-invasive prenatal testing (NIPT) and determine factors influencing their decisions around uptake of NIPT., Method: We conducted qualitative interviews to assess knowledge, attitude and deliberation amongst women offered NIPT in a public health service. In total, 45 women took part in telephone interviews (79% participation rate)., Results: Most women could recount the key aspects of NIPT discussed during pre-test counselling but had variable knowledge about Down syndrome. Analysis of women's attitudes towards undergoing NIPT revealed three dominant factors they considered when reflecting on the test: (1) how NIPT compared with alternative testing options, (2) reflections on coping and (3) moral or religious values. Exploring the deliberative process revealed the different paths women take when making decisions. For some, it was an extension of the decision to have Down syndrome screening; some considered it early on following the booking-in appointment; others made step-wise decisions about NIPT when it became relevant to them., Conclusion: Our findings support the importance of personalised counselling, whereby women and their partners have the opportunity to reflect on the implications of the test results in the context of their own lives and values. Our data highlight the influence of personal circumstances on decision-making. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd., (© 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.)

Objective:  To investigate the benefits and costs of implementing non-invasive prenatal testing (NIPT) for Down's syndrome into the NHS maternity care pathway., Design:  Prospective cohort study., Setting:  Eight maternity units across the United Kingdom between 1 November 2013 and 28 February 2015., Participants:  All pregnant women with a current Down's syndrome risk on screening of at least 1/1000., Main Outcome Measures:  Outcomes were uptake of NIPT, number of cases of Down's syndrome detected, invasive tests performed, and miscarriages avoided. Pregnancy outcomes and costs associated with implementation of NIPT, compared with current screening, were determined using study data on NIPT uptake and invasive testing in combination with national datasets., Results:  NIPT was prospectively offered to 3175 pregnant women. In 934 women with a Down's syndrome risk greater than 1/150, 695 (74.4%) chose NIPT, 166 (17.8%) chose invasive testing, and 73 (7.8%) declined further testing. Of 2241 women with risks between 1/151 and 1/1000, 1799 (80.3%) chose NIPT. Of 71 pregnancies with a confirmed diagnosis of Down's syndrome, 13/42 (31%) with the diagnosis after NIPT and 2/29 (7%) after direct invasive testing continued, resulting in 12 live births. In an annual screening population of 698 500, offering NIPT as a contingent test to women with a Down's syndrome screening risk of at least 1/150 would increase detection by 195 (95% uncertainty interval -34 to 480) cases with 3368 (2279 to 4027) fewer invasive tests and 17 (7 to 30) fewer procedure related miscarriages, for a non-significant difference in total costs (£-46 000, £-1 802 000 to £2 661 000). The marginal cost of NIPT testing strategies versus current screening is very sensitive to NIPT costs; at a screening threshold of 1/150, NIPT would be cheaper than current screening if it cost less than £256. Lowering the risk threshold increases the number of Down's syndrome cases detected and overall costs, while maintaining the reduction in invasive tests and procedure related miscarriages., Conclusions:  Implementation of NIPT as a contingent test within a public sector Down's syndrome screening programme can improve quality of care, choices for women, and overall performance within the current budget. As some women use NIPT for information only, the Down's syndrome live birth rate may not change significantly. Future research should consider NIPT uptake and informed decision making outside of a research setting., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Objective: Evaluate the costs of offering non-invasive prenatal diagnosis (NIPD) for single gene disorders compared to traditional invasive testing to inform NIPD implementation into clinical practice., Method: Total costs of diagnosis using NIPD or invasive testing pathways were compared for a representative set of single gene disorders., Results: For autosomal dominant conditions, where NIPD molecular techniques are straightforward, NIPD cost £314 less than invasive testing. NIPD for autosomal recessive and X-linked conditions requires more complicated technical approaches and total costs were more than invasive testing, e.g. NIPD for spinal muscular atrophy was £1090 more than invasive testing. Impact of test uptake on costs was assessed using sickle cell disorder as an example. Anticipated high uptake of NIPD resulted in an incremental cost of NIPD over invasive testing of £48 635 per 100 pregnancies at risk of sickle cell disorder., Conclusion: Total costs of NIPD are dependent upon the complexity of the testing technique required. Anticipated increased demand for testing may have economic implications for prenatal diagnostic services. Ethical issues requiring further consideration are highlighted including directing resources to NIPD when used for information only and restricting access to safe tests if it is not cost-effective to develop NIPD for rare conditions. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd., (© 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.)

Non-invasive prenatal testing is increasingly available worldwide and stakeholder viewpoints are essential to guide implementation. Here we compare the preferences of women and health professionals from nine different countries towards attributes of non-invasive and invasive prenatal tests for Down syndrome. A discrete choice experiment was used to obtain participants' stated preference for prenatal tests that varied according to four attributes: accuracy, time of test, risk of miscarriage, and type of information. Pregnant women and health professionals were recruited from Canada, Denmark, Iceland, Israel, Italy, the Netherlands, Portugal, Singapore, and the United Kingdom. A total of 2666 women's and 1245 health professionals' questionnaires were included in the analysis. Differences in preferences were seen between women and health professionals within and between countries. Overall, women placed greater emphasis on test safety and comprehensive information than health professionals, who emphasised accuracy and early testing. Differences between women's and health professionals' preferences are marked between countries. Varied approaches to implementation and service delivery are therefore needed and individual countries should develop guidelines appropriate for their own social and screening contexts.

Non-invasive prenatal testing (NIPT) using cell-free DNA for aneuploidy is a highly accurate screening test; however, concerns exist around the potential for routinisation of testing. The multidimensional measure of informed choice (MMIC) is a quantitative instrument developed to assess informed choice for Down syndrome screening (DSS). We have validated a modified MMIC for NIPT and measured informed choice among women offered NIPT in a public health service. The measure was distributed to women recruited across eight maternity units in the United Kingdom who had accepted DSS. Construct validity was assessed by simultaneously conducting qualitative interviews. Five hundred and eighty-five questionnaires were completed and 45 interviews conducted after blood-draw (or equivalent for those that declined NIPT). The measure demonstrated good internal consistency and internal validity. Results indicate the vast majority of women (89%) made an informed choice; 95% were judged to have good knowledge, 88% had a positive attitude and 92% had deliberated. Of the 11% judged to have made an uninformed choice, 55% had not deliberated, 41% had insufficient knowledge, and 19% had a negative attitude. Ethnicity (OR=2.78, P=0.003) and accepting NIPT (OR=16.05, P=0.021) were found to be significant predictors of informed choice. The high rate of informed choice is likely to reflect the importance placed on the provision of pre-test counselling in this study. It will be vital to ensure that this is maintained once NIPT is offered in routine clinical practice.

Non-invasive prenatal testing (NIPT) for aneuploidy is currently only available in the UK through the private sector outside of the research arena. As part of an implementation study in the UK National Health Service we conducted a mixed methods study to assess women's experience of being offered NIPT using validated measures of decisional conflict, decisional regret and anxiety. Clinical service preferences were also explored. Women with a Down syndrome screening risk >1:1000 were invited to take part in the study and offered NIPT, NIPT and invasive testing (for women with a risk above 1:150) or no further testing. A cross-sectional survey and semi-structured interviews were conducted at two time points; at the time of testing and one month following receipt of results (or equivalent for NIPT decliners). In total, 845 questionnaires and 81 interviews were analysed. The main motivation to accept NIPT was for reassurance (30.8%). Decisional conflict occurred in a minimal number of cases (3.8%), however, none of the participants experienced decisional regret. Around a third (29.9%) of women had elevated anxiety at the time of testing, including intermediate risk women who traditionally would not be offered further testing (54.4% high risk; 20.1% medium risk), a finding supported through the qualitative interviews where prolonged or additional anxiety was found to occur in some medium risk cases. Women were overwhelmingly positive about the opportunity to have a test that was procedurally safe, accurate, reduced the need for invasive testing and identified cases of Down syndrome that might otherwise have been missed. Reassurance was identified as the main motivator for accepting NIPT, particularly amongst medium risk women, with high risk women inclined to accept NIPT to inform decisions around invasive testing. The current turnaround time for test result was identified as a key limitation. All the women interviewed thought NIPT should be adopted as part of NHS clinical practice, with the majority favouring NIPT offered as a first-line test. Our study highlights the potential that NIPT has to positively impact women's experience of prenatal testing for aneuploidy.

Purpose of Review: To explore stakeholder views on cell-free DNA testing and highlight findings important for successful implementation and the provision of best practice in counseling., Recent Findings: Noninvasive tests based on the analysis of cell-free fetal DNA are now widely available in clinical practice and applications are expanding rapidly. It is essential that stakeholder views are considered in order to identify and address any ethical and social issues. We provide an overview of stakeholder viewpoints and then focus on the key issues of informed decision making, test uptake, service delivery and information sources., Summary: Stakeholders are positive about the introduction of cell-free fetal DNA testing into clinical practice. They describe both practical and psychological benefits arising from tests that are safe and can potentially be performed earlier in pregnancy. Key concerns, which include the potential for these tests to have a negative impact on informed decision making and increased societal pressure to have testing, can be addressed through careful parent-directed counseling. As applications for these tests expand it is increasingly important to develop innovative approaches to facilitate good understanding for parents who are offered noninvasive prenatal testing.

The use of massively parallel sequencing of maternal cfDNA for non-invasive prenatal testing (NIPT) of aneuploidy is widely available. Recently, the scope of testing has increased to include selected subchromosomal abnormalities, but the number of samples reported has been small. We developed a calling pipeline based on a segmentation algorithm for the detection of these rearrangements in maternal plasma. The same read depth used in our standard pipeline for aneuploidy NIPT detected 15/18 (83%) samples with pathogenic rearrangements > 6 Mb but only 2/10 samples with rearrangements < 6 Mb, unless they were maternally inherited. There were two false-positive calls in 534 samples with no known subchromosomal abnormalities (specificity 99.6%). Using higher read depths, we detected 29/31 fetal subchromosomal abnormalities, including the three samples with maternally inherited microduplications. We conclude that test sensitivity is a function of the fetal fraction, read depth, and size of the fetal CNV and that at least one of the two false negatives is due to a low fetal fraction. The lack of an independent method for determining fetal fraction, especially for female fetuses, leads to uncertainty in test sensitivity, which currently has implications for this technique's future as a clinical diagnostic test. Furthermore, to be effective, NIPT must be able to detect chromosomal rearrangements across the whole genome for a very low false-positive rate. Because standard NIPT can only detect the majority of larger (>6 Mb) chromosomal rearrangements and requires knowledge of fetal fraction, we consider that it is not yet ready for routine clinical implementation., (Copyright © 2016 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Our UK National Health Service regional genetics laboratory offers NIPD for autosomal dominant and de novo conditions (achondroplasia, thanataphoric dysplasia, Apert syndrome), paternal mutation exclusion for cystic fibrosis and a range of bespoke tests. NIPD avoids the risks associated with invasive testing, making prenatal diagnosis more accessible to families at high genetic risk. However, the challenge remains in offering definitive diagnosis for autosomal recessive diseases, which is complicated by the predominance of the maternal mutant allele in the cell-free DNA sample and thus requires a variety of different approaches. Validation and diagnostic implementation for NIPD of congenital adrenal hyperplasia (CAH) is further complicated by presence of a pseudogene that requires a different approach. We have used an assay targeting approximately 6700 heterozygous SNPs around the CAH gene (CYP21A2) to construct the high-risk parental haplotypes and tested this approach in five cases, showing that inheritance of the parental alleles can be correctly identified using NIPD. We are evaluating various measures of the fetal fraction to help determine inheritance of parental mutations. We are currently exploring the utility of an NIPD multi-disorder panel for autosomal recessive disease, to make testing more widely applicable to families with a variety of serious genetic conditions.

Background: The development of non-invasive prenatal testing has increased accessibility of fetal testing. Companies are now advertising prenatal testing for aneuploidy via the Internet., Objectives: The aim of this systematic review of websites advertising non-invasive prenatal testing for aneuploidy was to explore the nature of the information being provided to potential users., Methods: We systematically searched two Internet search engines for relevant websites using the following terms: 'prenatal test', 'antenatal test', 'non-invasive test', 'noninvasive test', 'cell-free fetal DNA', 'cffDNA', 'Down syndrome test' or 'trisomy test'. We examined the first 200 websites identified through each search. Relevant web-based text was examined, and key topics were identified, tabulated and counted. To analyse the text further, we used thematic analysis., Main Results: Forty websites were identified. Whilst a number of sites provided balanced, accurate information, in the majority supporting evidence was not provided to underpin the information and there was inadequate information on the need for an invasive test to definitely diagnose aneuploidy., Conclusions: The information provided on many websites does not comply with professional recommendations. Guidelines are needed to ensure that companies offering prenatal testing via the Internet provide accurate and comprehensible information., (© 2015 John Wiley & Sons, Ltd.)

This paper contains a joint ESHG/ASHG position document with recommendations regarding responsible innovation in prenatal screening with non-invasive prenatal testing (NIPT). By virtue of its greater accuracy and safety with respect to prenatal screening for common autosomal aneuploidies, NIPT has the potential of helping the practice better achieve its aim of facilitating autonomous reproductive choices, provided that balanced pretest information and non-directive counseling are available as part of the screening offer. Depending on the health-care setting, different scenarios for NIPT-based screening for common autosomal aneuploidies are possible. The trade-offs involved in these scenarios should be assessed in light of the aim of screening, the balance of benefits and burdens for pregnant women and their partners and considerations of cost-effectiveness and justice. With improving screening technologies and decreasing costs of sequencing and analysis, it will become possible in the near future to significantly expand the scope of prenatal screening beyond common autosomal aneuploidies. Commercial providers have already begun expanding their tests to include sex-chromosomal abnormalities and microdeletions. However, multiple false positives may undermine the main achievement of NIPT in the context of prenatal screening: the significant reduction of the invasive testing rate. This document argues for a cautious expansion of the scope of prenatal screening to serious congenital and childhood disorders, only following sound validation studies and a comprehensive evaluation of all relevant aspects. A further core message of this document is that in countries where prenatal screening is offered as a public health programme, governments and public health authorities should adopt an active role to ensure the responsible innovation of prenatal screening on the basis of ethical principles. Crucial elements are the quality of the screening process as a whole (including non-laboratory aspects such as information and counseling), education of professionals, systematic evaluation of all aspects of prenatal screening, development of better evaluation tools in the light of the aim of the practice, accountability to all stakeholders including children born from screened pregnancies and persons living with the conditions targeted in prenatal screening and promotion of equity of access.

Objective: To investigate whether the introduction of non-invasive pre-natal testing for Down's syndrome (DS) has the potential to undermine informed choice., Participants: Three hundred and ninety-three health professionals; 523 pregnant women., Methods: A cross-sectional questionnaire study across nine maternity units and three conferences in the UK designed to assess opinions regarding test delivery and how information should be communicated to women when offered Down's syndrome screening (DSS) or diagnosis using invasive (IDT) or non-invasive testing (NIPT)., Results: Both pregnant women and health professionals in the NIPT and DSS groups were less likely than the IDT group to consider that testing should take place at a return visit or that obtaining written consent was necessary, and more likely to think testing should be carried out routinely. Compared to health professionals, pregnant women expressed a stronger preference for testing to occur on the same day as pre-test counselling (P = 0.000) and for invasive testing to be offered routinely (P = 0.000). They were also more likely to indicate written consent as necessary for DSS (P = 0.000) and NIPT (P < 0.05)., Conclusions: Health professionals and pregnant women view the consenting process differently across antenatal test types. These differences suggest that informed choice may be undermined with the introduction of NIPT for DS into clinical practice. To maintain high standards of care, effective professional training programmes and practice guidelines are needed which prioritize informed consent and take into account the views and needs of service users., (© 2014 John Wiley & Sons Ltd.)

Objective: In the absence of aneuploidy or other pathogenic cytogenetic abnormality, fetuses with increased nuchal translucency (NT ≥ 3.5 mm) and/or other sonographic abnormalities have a greater incidence of genetic syndromes, but defining the underlying pathology can be challenging. Here, we investigate the value of whole exome sequencing in fetuses with sonographic abnormalities but normal microarray analysis., Method: Whole exome sequencing was performed on DNA extracted from chorionic villi or amniocytes in 24 fetuses with unexplained ultrasound findings. In the first 14 cases sequencing was initially performed on fetal DNA only. For the remaining 10, the trio of fetus, mother and father was sequenced simultaneously., Results: In 21% (5/24) cases, exome sequencing provided definitive diagnoses (Milroy disease, hypophosphatasia, achondrogenesis type 2, Freeman-Sheldon syndrome and Baraitser-Winter Syndrome). In a further case, a plausible diagnosis of orofaciodigital syndrome type 6 was made. In two others, a single mutation in an autosomal recessive gene was identified, but incomplete sequencing coverage precluded exclusion of the presence of a second mutation., Conclusion: Whole exome sequencing improves prenatal diagnosis in euploid fetuses with abnormal ultrasound scans. In order to expedite interpretation of results, trio sequencing should be employed, but interpretation can still be compromised by incomplete coverage of relevant genes., (© 2015 John Wiley & Sons, Ltd.)

Prenatal testing based on cell-free fetal DNA in maternal serum is now possible for specific monogenic conditions, and studies have shown that the use of non-invasive testing is supported by prospective parents and health professionals. However, some ethical issues have been raised concerning informed consent and paternal rights. The objective of this study was to explore ethical aspects of the use of non-invasive prenatal diagnostic testing for autosomal recessive disorders. We used a qualitative cross-sectional design, based on Thematic Analysis, and recruited 27 individuals of reproductive age who were carriers of one of four conditions: thalassaemia, sickle cell disease, cystic fibrosis or spinal muscular atrophy. Data were collected via focus groups or interviews. Participants were aware of the potential for such tests to be viewed as routine and suggested that obtaining written consent and allowing time for consideration is needed to facilitate autonomous choice and informed consent. All participants felt that mothers should be able to request such tests, but fathers who declined carrier testing should be made aware that fetal test results may reveal their status. We suggest that a written record of consent for non-invasive prenatal diagnosis should be used as a standard to help reinforce the serious nature of the test results. Where the father's carrier status could be revealed through fetal testing, he should be made aware of this before the results are available. Health professionals should discuss with the pregnant woman the best way to manage unsought information about the father's carrier status to minimise family disruption.

The identification of cell-free fetal DNA (cffDNA) in maternal plasma in 1997 heralded the most significant change in obstetric care for decades, with the advent of safer screening and diagnosis based on analysis of maternal blood. Here, we describe how the technological advances offered by next-generation sequencing have allowed for the development of a highly sensitive screening test for aneuploidies as well as definitive prenatal molecular diagnosis for some monogenic disorders., (Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.)

Objective: To investigate how non-invasive prenatal testing (NIPT) is portrayed in the UK press media., Methods: Content analysis of the ten most widely circulated print/digital news sources in the UK., Results: Seventy-nine articles were identified focusing on NIPT for Down syndrome (n = 67) including single gene disorders (n = 5), whole genome sequencing (n = 8), NIPT technology (n = 2), Rhesus D (n = 1) and fetal sex determination (n = 1). The majority (63%) were in 'serious' papers. Test attributes were frequently cited (100%), in particular that NIPT is a blood test (89%) and avoids risk of miscarriage (56%). The main psychosocial benefit reported was increased time for decision-making (15%). Concerns were discussed less frequently than benefits (39%), with increase in termination rates the main concern raised (23%). The majority of headlines (52%) projected a positive frame towards NIPT. Regarding overall framing of articles, over two thirds (68%) presented benefits and concerns or limitations; however, only a third (35%) were considered 'balanced'., Conclusion: Positive reporting of NIPT in the UK news media reflects the publics' broadly optimistic view towards genomic technology and prenatal testing. Health professionals should be aware that women may have incomplete information or misunderstandings about NIPT. Pre-test counselling to ensure informed decision-making is therefore important., (© 2014 John Wiley & Sons, Ltd.)

Background: Congenital high airway obstruction syndrome (CHAOS) is a rare life-threatening condition characterised by complete or near-complete developmental obstruction of the foetal airway. Although antenatal imaging findings have been described, the postmortem MRI findings have not been reported., Objective: To present postmortem MRI features of CHAOS., Materials and Methods: We retrospectively reviewed our hospital pathology and imaging databases for cases of CHAOS over a 2-year period., Results: We identified two cases of CHAOS. In both cases, postmortem plain radiographs demonstrated gross abdominal distension with distortion and splaying of the rib cage. Both foetuses had characteristic postmortem MRI findings including large-volume fluid-filled lungs on T2-weighted imaging, diaphragmatic eversion, fluid-filled airway dilatation below the level of obstruction, centrally positioned and compressed heart, and massive ascites. One foetus had an associated limb abnormality., Conclusion: Postmortem MRI in foetuses suspected of having CHAOS allows confirmation of the diagnosis, determination of the anatomical level of the atresia or stenosis, and identification of associated abnormalities without the need for invasive autopsy.

Unlabelled: Non-invasive prenatal testing (NIPT) of fetal aneuploidy using cell-free fetal DNA is becoming part of routine clinical practice. RAPIDR (Reliable Accurate Prenatal non-Invasive Diagnosis R package) is an easy-to-use open-source R package that implements several published NIPT analysis methods. The input to RAPIDR is a set of sequence alignment files in the BAM format, and the outputs are calls for aneuploidy, including trisomies 13, 18, 21 and monosomy X as well as fetal sex. RAPIDR has been extensively tested with a large sample set as part of the RAPID project in the UK. The package contains quality control steps to make it robust for use in the clinical setting., Availability and Implementation: RAPIDR is implemented in R and can be freely downloaded via CRAN from here: http://cran.r-project.org/web/packages/RAPIDR/index.html., Contact: kitty.lo@ucl.ac.uk, Supplementary Information: Supplementary data are available at Bioinformatics online., (© The Author 2014. Published by Oxford University Press.)

Non-invasive prenatal diagnosis and testing by analysis of cell-free DNA in the maternal circulation is a rapidly evolving field. Current clinical applications include fetal sex determination, fetal rhesus D determination, the diagnosis of some single gene disorders, and a highly accurate screening test for aneuploidies. In the future it is likely to be used for the diagnosis of an increasing range of monogenic disorders, and may even be used to profile entire fetal genomes. The introduction of these tests into clinical practice brings clear benefits but also poses several ethical, social and service delivery challenges. Here, we discuss the current clinical applications, discuss some of the technical and ethical challenges, and look to what the future might bring as technology continues to evolve., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)