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Commentary| Volume 17, ISSUE 12, P958-961, December 2015

Too much, too soon?: Commercial provision of noninvasive prenatal screening for subchromosomal abnormalities and beyond

      I was not informed of the new micro deletion portion of [NIPS] and that it was basically experimental. I tested positive for 1p36 and chose amniocentesis to confirm or deny. The amnio was done at 15 weeks because we would have terminated for 1p36… the amnio showed normal genes… I would never do this screening again and am so frustrated that these tests are released without having them validated in a low risk population or against actual tests like amnio. The amount of trauma and stress that this brought was just horrible. (Personal correspondence, NIPS customer. Information has been edited to preserve anonymity.)
      Noninvasive prenatal screening (NIPS) using cell-free fetal DNA has been commercially available in the United States since 2011 for the detection of trisomies 13 (Patau syndrome), 18 (Edwards syndrome), and 21 (Down syndrome). Five companies—Sequenom, Natera, Ariosa Diagnostics, Verinata Health, and Integrated Genetics—currently market NIPS in the United States. The perceived benefits of this technology, which include the lack of procedure-related risk associated with invasive testing while achieving higher sensitivity and specificity than serum screening, have led to rapid adoption by patients and providers, coverage by several third-party payers, and commercial success.

      Karow J. NIPS continues to take off in 2013 as indications, insurance coverage grow. GenomeWeb 2 January 2014.

      , The state of California recently announced that it would add NIPS for aneuploidy testing to its universal prenatal screening program as a second-tier screen,

      Flessel M, Goldman S. California prenatal screening program to include noninvasive testing. ACOG, September 2013. http://www.acog.org/About-ACOG/ACOG-Departments/District-Newsletters/District-IX/September-2013/California-Prenatal-Screening-Program.

      and some state-based testing programs and Medicaid plans now reimburse for NIPS.
      Since they were introduced, NIPS panels have added fetal sex and sex chromosome aneuploidies, including XXY (Klinefelter syndrome), XYY syndrome, and monosomy X (Turner syndrome) (see for example http://www.illumina.com/clinical/reproductive-genetic-health/clinical-labs/nipt.html). Natera and Sequenom also began offering expanded test panels that claim to detect subchromosomal abnormalities (SCAs), including 22q (DiGeorge syndrome), 5p (Cri-du-chat syndrome), 15q (Prader-Willi/Angelman syndromes), and 1p36 deletion syndrome (http://www.panoramatest.com). Sequenom later added microdeletions in chromosomes 11 (Jacobsen syndrome), 8 (Langer-Giedion syndrome), and 4 (Wolf-Hirschhorn syndrome) (see https://laboratories.sequenom.com/patients/maternit21-plus/). Several companies worldwide now offer NIPS microdeletion panels (Table 1) because, they assert, the conditions in question are severe and the information has clinical utility. For instance, prenatal information about 22q11.2 deletions may allow physicians and families to prepare for the delivery of a child in a specialty cardiac care center.
      • Driscoll D.A.
      Prenatal diagnosis of the 22q11.2 deletion syndrome.
      But observers have argued that the clinical utility of some of the expanded content is questionable and that lumping trisomy testing and SCA testing into the same test conflates disparate clinical realities.
      • Vora N.L.
      • O’Brien B.M.
      Noninvasive prenatal testing for microdeletion syndromes and expanded trisomies: proceed with caution.
      Table 1Commercial offering of noninvasive prenatal screening for subchromosomal abnormalities

      Validation

      The commercial provision of NIPS for subchromosomal anomalies raises several concerns in addition to the question of clinical utility. Before offering tests for trisomies 13, 18, and 21, several companies conducted large-scale validation trials.
      • Zimmermann B.
      • Hill M.
      • Gemelos G.
      Noninvasive prenatal aneuploidy testing of chromosomes 13, 18, 21, X, and Y, using targeted sequencing of polymorphic loci.
      ,
      • Nicolaides K.H.
      • Syngelaki A.
      • Gil M.
      • Atanasova V.
      • Atanasova V.
      • Markova D.
      Validation of targeted sequencing of single-nucleotide polymorphisms for non-invasive prenatal detection of aneuploidy of chromosomes 13, 18, 21, X, and Y.
      ,
      • Norton M.E.
      • Brar H.
      • Weiss J.
      Non-invasive chromosomal evaluation (NICE) study: results of a multicenter prospective cohort study for detection of fetal trisomy 21 and trisomy 18.
      ,
      • Porreco R.P.
      • Garite T.J.
      • Maurel K.
      Noninvasive prenatal screening for fetal trisomies 21, 18, 13 and the common sex chromosome aneuploidies from maternal blood using massively parallel genomic sequencing of DNA.
      ,
      • Bianchi D.W.
      • Parker R.L.
      • Wentworth J.
      DNA sequencing versus standard prenatal aneuploidy screening.
      Peer-reviewed publications demonstrating high sensitivity (between 98.0 and 99.0%) and specificity (between 99.5% and 99.8%) were important to the uptake of NIPS by providers and payers. High specificity, in particular, is considered important in prenatal genetic testing because a reduction in false positives allows clinicians to avoid unnecessary invasive procedures that carry a small risk of miscarriage.
      NIPS for SCAs has not been validated in large-scale studies, although a few reports of limited cases have been published in the peer-reviewed literature
      • Pergament E.
      • Cuckle H.
      • Zimmermann B.
      Single-nucleotide polymorphism-based noninvasive prenatal screening in a high-risk and low-risk cohort.
      ,
      • Srinivasan A.
      • Bianchi D.W.
      • Huang H.
      • Sehnert A.J.
      • Rava R.P.
      Noninvasive detection of fetal subchromosome abnormalities via deep sequencing of maternal plasma.
      ,
      • Rabinowitz M.
      • Savage M.
      • Pettersen B.
      • Sigurjonsson S.
      • Hill M.
      • Zimmermann B.
      Noninvasive cell-free DNA-based prenatal detection of microdeletions using single nucleotide polymorphism-targeted sequencing.
      or presented at scientific meetings.
      • Dharajiya N.
      • Monroe T.
      • Boomer T.
      • Jenna W.
      • Jesiolowski J.
      • Salvidar J.
      NIPS 2.0: identification of 22q microdeletions by non-invasive prenatal testing.
      Sex chromosome aneuploidies have been included in some validation studies, but researchers acknowledge that the positive predictive value of these conditions is low.
      • Porreco R.P.
      • Garite T.J.
      • Maurel K.
      Noninvasive prenatal screening for fetal trisomies 21, 18, 13 and the common sex chromosome aneuploidies from maternal blood using massively parallel genomic sequencing of DNA.
      ,
      • Mazloom A.R.
      • Džakula Ž
      • Oeth P.
      Noninvasive prenatal detection of sex chromosomal aneuploidies by sequencing circulating cell-free DNA from maternal plasma.
      ,
      • Samango-Sprouse C.
      • Banjevic M.
      • Ryan A.
      SNP-based non-invasive prenatal testing detects sex chromosome aneuploidies with high accuracy.
      With rare conditions, large clinical validation studies become less feasible; the rarity of the conditions has a negative impact on the positive predictive value and negative predictive value of tests. Statistically, NIPS for SCAs and sex chromosome aneuploidies will yield more false positives than tests for more common conditions such as trisomy 21, and anecdotal accounts from physicians, patients, and genetic counselors concur. This leads to an increase in confirmatory invasive testing, thus eroding the benefits of NIPS in reducing unnecessary invasive procedures needed to confirm common trisomies. Without accurate information about the positive predictive value and negative predictive value of SCAs, clinicians may make uninformed decisions about ordering these tests and interpret test results inaccurately. Furthermore, patients and providers may see NIPS as a way to avoid invasive microarray testing despite the fact that invasive testing remains the gold standard for diagnosing SCAs.
      The offer of NIPS is currently recommended in “high-risk” pregnancies in general: pregnancies of women with advanced maternal age, pregnancies in which an ultrasound abnormality is detected, or when there is a history of chromosomal defects. Because the risk of trisomy 21 and other chromosomal aneuploidies increases with maternal age, the validation studies of NIPS for common trisomies were carried out in high-risk pregnancies for which an invasive test was already recommended. But the target patient population for SCA screening does not correlate with that of trisomies. SCAs occur with equal frequency at all maternal ages; the relative risk of subchromosomal aberrations is therefore higher for women with a lower maternal age than those of advanced maternal age. Moreover, many SCAs are not associated with clear ultrasound abnormalities, raising questions about what constitutes a “high-risk” pregnancy for these conditions.
      Data from recent clinical validation studies showed that NIPS for trisomies 13, 18, and 21 in “average-risk” women has sensitivity and specificity similar to those of high-risk women,
      • Bianchi D.W.
      • Parker R.L.
      • Wentworth J.
      DNA sequencing versus standard prenatal aneuploidy screening.
      ,
      • Pergament E.
      • Cuckle H.
      • Zimmermann B.
      Single-nucleotide polymorphism-based noninvasive prenatal screening in a high-risk and low-risk cohort.
      meaning that some providers may soon offer NIPS in all pregnancies. The impact of this shift using expanded panels may be significant, leading to a greatly expanded number of women receiving unvalidated test results for rare conditions.

      Counseling and Consent

      This expansion raises difficult issues in the context of genetic counseling. Screening for trisomy 21 and, to a lesser extent, trisomies 13 and 18 has been in place for many years. There are numerous educational resources, patient support groups, guidelines on returning results, and expert scholarship on the psychology of interpreting and delivering a Down syndrome diagnosis.
      • Sheets K.B.
      • Crissman B.G.
      • Feist C.D.
      Practice guidelines for communicating a prenatal or postnatal diagnosis of Down syndrome: recommendations of the national society of genetic counselors.
      ,
      • Kellogg G.
      • Slattery L.
      • Hudgins L.
      • Ormond K.
      Attitudes of mothers of children with down syndrome towards noninvasive prenatal testing.
      ,
      • Down Syndrome Diagnosis Study Group
      Prenatal diagnosis of Down syndrome: how best to deliver the news.
      Even in the majority of obstetric/family practices that do not include genetic counselors, most clinicians have a working knowledge of the physical and social profile of Down syndrome and can counsel potential parents on their options. By contrast, data from clinical experiences with NIPS demonstrate that interpretation and counseling in the context of screening for sex chromosome aneuploidies, in particular X chromosome aneuploidies, is more complicated
      • Hall S.
      • Abramsky L.
      • Marteau T.M.
      Health professionals’ reports of information given to parents following the prenatal diagnosis of sex chromosome anomalies and outcomes of pregnancies: a pilot study.
      ,
      • Abramsky L.
      • Hall S.
      • Levitan J.
      • Marteau T.M.
      What parents are told after prenatal diagnosis of a sex chromosome abnormality: interview and questionnaire study.
      ,
      • Tartaglia N.
      • Ayari N.
      • Howell S.
      • D’Epagnier C.
      • Zeitler P.
      48,XXYY, 48,XXXY and 49,XXXXY syndromes: not just variants of Klinefelter syndrome.
      ,
      • Herlihy A.S.
      • Halliday J.
      • McLachlan R.I.
      • Cock M.
      • Gillam L.
      Assessing the risks and benefits of diagnosing genetic conditions with variable phenotypes through population screening: Klinefelter syndrome as an example.
      ,
      • Visootsak J.
      • Ayari N.
      • Howell S.
      • Lazarus J.
      • Tartaglia N.
      Timing of diagnosis of 47,XXY and 48,XXYY: a survey of parent experiences.
      ,
      • Bardsley M.Z.
      • Kowal K.
      • Levy C.
      47,XYY syndrome: clinical phenotype and timing of ascertainment.
      ; NIPS for sex chromosome aneuploidies is increasingly uncovering incidental findings in the pregnant woman rather than the fetus.
      • Wang Y.
      • Chen Y.
      • Tian F.
      Maternal mosaicism is a significant contributor to discordant sex chromosomal aneuploidies associated with noninvasive prenatal testing.
      This complicates the already problematic process of counseling for sex chromosome abnormalities and requires additional resources to help families understand the clinical significance of these incidental findings.
      This is even truer of SCAs. Even if testing is restricted to clinically actionable conditions, whether most clinicians are well versed in the advances in NIPS or the clinical management of rare conditions is not clear.
      • Norton M.E.
      • Rose N.C.
      • Benn P.
      Noninvasive prenatal testing for fetal aneuploidy: clinical assessment and a plea for restraint.
      ,
      • Bensend T.A.
      • Veach P.M.
      • Niendorf K.B.
      What’s the harm? Genetic counselor perceptions of adverse effects of genetics service provision by non-genetics professionals.
      Prenatal genetic counseling is rarely considered a reimbursable expense by third-party payers, meaning that the number of practices that can afford to support prenatal counseling services will remain limited. While some testing companies offer telephone counseling services as part of their business model, whether this will be sufficient to address the rising need is far from clear, and there are concerns about conflicts of interest.

      Pollack A. Conflict potential seen in genetic counselors. New York Times 13 July2012.

      ,
      • Swanson A.
      • Ramos E.
      • Snyder H.
      Next generation sequencing is the impetus for the next generation of laboratory-based genetic counselors.
      For the most part, physicians or other care providers who order these tests will have to counsel patients themselves.
      • Benn P.
      • Chapman A.R.
      • Erickson K.
      Obstetricians and gynecologists’ practice and opinions of expanded carrier testing and noninvasive prenatal testing.
      The panel of subchromosomal conditions currently offered is significantly smaller than those included in prenatal chromosomal microarrays, which are increasingly used in invasive prenatal testing. However, recent research demonstrates that NIPS may be used to detect genome-wide variations in chromosomal copy number,
      • Ehrich M.
      • Deciu C.
      • Zhao C.Z.
      Genome wide analysis of sub chromosomal copy number variations using NIPS in >4500 patients (Abstract).
      and companies are likely to report more SCAs in the future. This expansion of NIPS will further increase false-positive rates, possibly leading to more anxiety and more follow-up invasive procedures. Equally concerning is the possibility of higher number of false negatives, which may lead to false reassurance, especially if there are no ultrasound abnormalities detected at 9–11 weeks’ gestation, when NIPS is frequently ordered.
      Some companies also include an expanded panel of SCAs as an opt-out test on the test requisition form. This approach not only fails to acknowledge the clinical differences between testing for trisomies versus SCAs, but failing to check the “opt-out” box may result in a failure of informed consent, leading families to receive information they do not want.
      • Bennett R.
      Antenatal genetic testing and the right to remain in ignorance.
      On the other hand, while an “opt-in” model may encourage explicit discussions about potential outcomes, physicians may be concerned that a failure to recommend expanded testing will lead to wrongful birth lawsuits.
      • Dickens B.M.
      Ethical and legal aspects of noninvasive prenatal genetic diagnosis.
      ,
      • Hassan M.
      • Chitty L.
      • Reardon H.
      Wrongful birth: clinical settings and legal implications.

      Conclusion

      The expansion in NIPS is driven, at least in part, by for-profit companies striving to differentiate themselves in a highly competitive market. The field remains litigious, creating uncertainty and pressure to secure market share.
      • Agarwal A.
      • Sayres L.C.
      • Cho M.K.
      • Cook-Deegan R.
      • Chandrasekharan S.
      Commercial landscape of noninvasive prenatal testing in the United States.
      While noninvasive SCA testing is a potentially beneficial development for some pregnancies, test menus and how they are offered should be actively monitored to identify ethical and clinical concerns. For instance, testing companies frequently advertise high sensitivity and sensitivity for NIPS. When testing for SCAs, however, providers should provide greater transparency about the actual positive predictive value and negative predictive value of these panels. Extra attention should be given to the consent process so that patients do not “accidentally” opt in to SCA testing. Similarly, payers should monitor how microdeletion tests are ordered and subsequent testing outcomes, especially to identify costs of unnecessary follow-up testing as a result of false positives. They should continue to systematically evaluate NIPS for coverage decisions, especially as the number of women receiving NIPS expands.
      Professional and academic communities have begun to systematically gather and analyze real-world data for NIPS for chromosomal aneuploidies, providing insight into the performance of these tests. Beginning to collect data on the performance of NIPS for SCAs is equally important. Professional societies have not provided explicit guidance on the use of NIPS for microdeletion testing and should do so quickly because test menus continue to expand. Companies should also consider voluntarily reporting aggregate data about SCAs to public databases, especially for variants of unknown significance. As NIPS platforms continue to evolve, head-to-head comparisons between approaches (i.e., array versus massively parallel sequencing) and current gold-standard methods should be conducted to inform clinical practice guidelines. These strategies may assist all stakeholders in ensuring ethical and beneficial translation of NIPS as it moves toward genome-wide analysis.

      Disclosure

      The authors declare no conflict of interest.

      Acknowledgements

      S.C. is supported by funding from the National Institutes of Health (R01HG007074) and the Duke Center for Public Genomics (P50HG03391).

      Author Contributions

      Megan Allyse and Subhashini Chandrasekharan: M.A. and S.C. contributed equally to this work.
      An erratum to this article is available online at https://doi.org/10.1038/gim.2015.64.

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