1
|
Pan Y, Pan X, Zhuang D, Zhou Y, Xue J, Wu S, Chen C, Li H. A statistical investigation of parameters associated with low cell-free fetal DNA fraction in maternal plasma for noninvasive prenatal testing. J Matern Fetal Neonatal Med 2024; 37:2338440. [PMID: 38604949 DOI: 10.1080/14767058.2024.2338440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 03/27/2024] [Indexed: 04/13/2024]
Abstract
BACKGROUND Noninvasive prenatal testing (NIPT) is the most common method for prenatal aneuploidy screening. Low fetal fraction (LFF) is the primary reason for NIPT failure. Consequently, factors associated with LFF should be elucidated for optimal clinical implementation of NIPT. METHODS In this study, NIPT data from January 2019 to December 2022 from the laboratory records and obstetrical and neonatal data from the electronic medical records were collected and analyzed. Subjects with FF >3.50% were assigned to the control group, subjects with FF <3.50% once were assigned to the LFF group, and subjects with FF <3.50% twice were assigned to the repetitive low fetal fraction (RLFF) group. Factors, including body mass index (BMI), gestational age, maternal age, twin pregnancy, and in vitro fertilization (IVF) known to be associated with LFF were assessed by Kruskal-Wallis H test and logistic regression. Clinical data on first trimester pregnancy-associated plasma protein-A (PAPP-A), beta-human chorionic gonadotropin (β-hCG), gestational age at delivery, birth weight at delivery, and maternal diseases were obtained from the hospital's prenatal and neonatal screening systems (twin pregnancy was not included in the data on gestational age at delivery and the control group did not include data on maternal diseases.), and were analyzed using Kruskal-Wallis H test and Chi-square test. RESULTS Among the total of 63,883 subjects, 63,605 subjects were assigned to the control group, 197 subjects were assigned to the LFF group, and 81 subjects were assigned to the RLFF group. The median of BMI in the three groups was 22.43 kg/m2 (control), 25.71 kg/m2 (LFF), and 24.54 kg/m2 (RLFF). The median gestational age in the three groups was 130 days (control), 126 days (LFF), and 122/133 days (RLFF). The median maternal age in the three groups was 29 (control), 29 (LFF), and 33-years-old (RLFF). The proportion of twin pregnancies in the three groups was 3.3% (control), 10.7% (LFF), and 11.7% (RLFF). The proportion of IVF in the three groups was 4.7% (control), 11.7% (LFF), and 21.3% (RLFF). The factors significantly associated with LFF included BMI [2.18, (1.94, 2.45), p < 0.0001], gestational age [0.76, (0.67, 0.87), p < 0.0001], twin pregnancy [1.62, (1.02, 2.52), p = 0.0353], and IVF [2.68, (1.82, 3.86), p < 0.0001]. The factors associated with RLFF included maternal age [1.54, (1.17, 2.05), p = 0.0023] and IVF [2.55, (1.19, 5.54), p = 0.016]. Multiples of the median (MOM) value of β-hCG and pregnant persons' gestational age at delivery were significantly decreased in the LFF and RLFF groups compared to the control group. CONCLUSION According to our findings based on the OR value, factors associated strongly with LFF include a high BMI and the use of IVF. Factors associated less strongly with LFF include early gestational age and twin pregnancy, while advanced maternal age and IVF were independent risk factors for a second LFF result.
Collapse
Affiliation(s)
- Yun Pan
- The Central Laboratory of Birth Defects Prevention and Control, Women and Children's Hospital of Ningbo University, Ningbo, China
- Ningbo Key Laboratory for the Prevention and Treatment of Embryogenic Diseases, Women and Children's Hospital of Ningbo University, Ningbo, China
| | - Xiaoli Pan
- The Central Laboratory of Birth Defects Prevention and Control, Women and Children's Hospital of Ningbo University, Ningbo, China
- Ningbo Key Laboratory for the Prevention and Treatment of Embryogenic Diseases, Women and Children's Hospital of Ningbo University, Ningbo, China
| | - Danyan Zhuang
- The Central Laboratory of Birth Defects Prevention and Control, Women and Children's Hospital of Ningbo University, Ningbo, China
- Ningbo Key Laboratory for the Prevention and Treatment of Embryogenic Diseases, Women and Children's Hospital of Ningbo University, Ningbo, China
| | - Ying Zhou
- The Central Laboratory of Birth Defects Prevention and Control, Women and Children's Hospital of Ningbo University, Ningbo, China
- Ningbo Key Laboratory for the Prevention and Treatment of Embryogenic Diseases, Women and Children's Hospital of Ningbo University, Ningbo, China
| | - Jiangyang Xue
- The Central Laboratory of Birth Defects Prevention and Control, Women and Children's Hospital of Ningbo University, Ningbo, China
- Ningbo Key Laboratory for the Prevention and Treatment of Embryogenic Diseases, Women and Children's Hospital of Ningbo University, Ningbo, China
| | - Shanshan Wu
- Paediatric Surgery Center, Women and Children's Hospital of Ningbo University, Ningbo, China
| | - Changshui Chen
- Ningbo Key Laboratory for the Prevention and Treatment of Embryogenic Diseases, Women and Children's Hospital of Ningbo University, Ningbo, China
| | - Haibo Li
- The Central Laboratory of Birth Defects Prevention and Control, Women and Children's Hospital of Ningbo University, Ningbo, China
- Ningbo Key Laboratory for the Prevention and Treatment of Embryogenic Diseases, Women and Children's Hospital of Ningbo University, Ningbo, China
| |
Collapse
|
2
|
Benn P, Zhang J, Lyons D, Xu W, Leonard S, Demko Z. Accuracy of fetal fraction measurements in a single-nucleotide polymorphism-based noninvasive prenatal test. Prenat Diagn 2024. [PMID: 38991760 DOI: 10.1002/pd.6634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/30/2024] [Accepted: 07/03/2024] [Indexed: 07/13/2024]
Abstract
BACKGROUND Noninvasive prenatal testing (NIPT) for fetal aneuploidy relies on the analysis of fetoplacental cell-free DNA (cfDNA) found in maternal plasma. A minimum cfDNA fetal fraction (FF) is required for reliable test performance, but some methods may have suboptimal accuracy for FF measurement. This study investigated the accuracy of a single-nucleotide polymorphism- (SNP-) based NIPT method to assess FF. METHODS FF measurements using SNP-based NIPT in consecutive samples from singleton male pregnancies were compared with FF measured using a "gold standard" Y-chromosome method. RESULTS In a cohort of 106,846 samples, the SNP-based FF method showed a standard deviation (SD) of 0.42%. Compared to the Y chromosome FF method, a correlation coefficient, r, of 0.995, and bias of 0.17% were observed. The SD was not substantially different across specific FF ranges or for samples with high-risk NIPT results. CONCLUSIONS The SNP-based NIPT method estimates FF with good accuracy, with a SD three to eight times better than other NIPT methods (0.42% vs. 1.3%-3.4%). FF is an important quality control parameter and should be routinely reported as part of NIPT.
Collapse
Affiliation(s)
- Peter Benn
- University of Connecticut Health Center, Farmington, Connecticut, USA
| | | | | | - Wenbo Xu
- Natera, Inc., Austin, Texas, USA
| | | | | |
Collapse
|
3
|
Liu G. Chromosomal aberration analysis: Novel noninvasive techniques for early-stage cancer screening. Clin Chim Acta 2024; 560:119736. [PMID: 38763468 DOI: 10.1016/j.cca.2024.119736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/07/2024] [Accepted: 05/14/2024] [Indexed: 05/21/2024]
Abstract
OBJECTIVE Chromosome breakage is a catastrophic event that leads to the progressive development and progression of cancer. In order to analyze the changes of peripheral blood microenvironment of tumor patients, to explore the indicators of non-specific non-invasive tumor early screening. This paper presents a new idea of whether the gene sequence near the DNA damage break point is the gene sequence that controls the unrestricted growth of normal cells. METHODS The chromosomal aberrations of peripheral blood lymphocytes were analysed in 60 healthy adult and 49 cancer patients before radiotherapy. RESULTS The detection rate of chromosomal aberrations was high in tumor patients, and "dicentric + translocations" of chromosomes were detected in 36 patients (73.47 %). The chi-square test showed statistically significant differences (P < 0.01), and chromosome adhesion and dissolution were observed. CONCLUSIONS "Dicentric + Translocation" chromosome can be used as a nonspecific early screening indicator for cancer. This is worthy of further study. This index can be used to determine the genetic basis of various cancers at the gene level to modify the base sequence and prevent the occurrence of cancer. It is worthy of further study, and it can provide a new method for gene therapy of tumors.
Collapse
Affiliation(s)
- Gang Liu
- Gansu Provincial Center for Disease Control and Prevention, (Joint Laboratory of Institute of Radiology, Chinese Academy of Medical Sciences), NO.310 Donggang West Road, Lanzhou, Gansu, China.
| |
Collapse
|
4
|
Claudel N, Barrois M, Vivanti AJ, Rosenblatt J, Salomon LJ, Jouannic JM, Picone O, Carbillon L, Vialard F, Launay E, Tsatsaris V, Curis E, El Khattabi L. Non-invasive cell-free DNA prenatal screening for trisomy 21 as part of primary screening strategy in twin pregnancy. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2024; 63:807-814. [PMID: 37470702 DOI: 10.1002/uog.26311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 05/27/2023] [Accepted: 05/31/2023] [Indexed: 07/21/2023]
Abstract
OBJECTIVES The performance of non-invasive prenatal screening using cell-free DNA testing of maternal blood in twin pregnancy is underevaluated, while serum marker-based strategies yield poor results. This study aimed to assess the performance of non-invasive prenatal screening for trisomy 21 in twin pregnancy as a first-tier test. Secondary objectives were to assess its failure rate and factors associated with failure. METHODS This retrospective cohort study included twin pregnancies in which non-invasive prenatal screening using cell-free DNA was performed as the primary screening strategy between May 2017 and October 2019. We used the NIPT VeriSeq® test for in-vitro diagnosis and set a fetal fraction cut-off of 4% for monochorionic pregnancies and 8% for dichorionic ones. Clinical data and pregnancy outcome were collected from physicians or midwives via a questionnaire or were retrieved directly on-site. We calculated the performance of non-invasive cell-free DNA screening for trisomy 21, analyzed its failure rate and assessed potentially associated factors. RESULTS Among 1885 twin pregnancies with follow-up, there were six (0.32%) confirmed cases of trisomy 21. The sensitivity of non-invasive prenatal screening for trisomy 21 was 100% (95% CI, 54.1-100%) and the false-positive rate was 0.23% (95% CI, 0.06-0.59%). The primary failure rate was 4.6%, with 4.0% being due to insufficient fetal fraction. A successful result was obtained for 65.4% of women who underwent a new blood draw, reducing the overall failure rate to 2.8%. Maternal body mass index, gestational age at screening as well as chorionicity were significantly associated with the risk of failure. CONCLUSION This study provides further evidence of the high performance, at an extremely low false-positive rate, of non-invasive prenatal screening in twins as part of a primary screening strategy for trisomy 21. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
Collapse
Affiliation(s)
- N Claudel
- Maternité Port Royal, AP-HP Hôpital Cochin, FHU Prema, Paris, France
- Université Paris Cité, Paris, France
- INSERM UMR_S1139, Paris, France
| | - M Barrois
- Maternité Port Royal, AP-HP Hôpital Cochin, FHU Prema, Paris, France
- Université Paris Cité, Paris, France
- INSERM UMR_S1139, Paris, France
| | - A J Vivanti
- Service de Gynécologie-Obstétrique, DMU Santé des Femmes et des Nouveau-nés, AP-HP Hôpital Antoine Béclère, Clamart, France
- Université Paris-Saclay, Orsay, France
| | - J Rosenblatt
- Service de Gynécologie-Obstétrique, AP-HP Hôpital Universitaire Robert-Debré, Paris, France
| | - L J Salomon
- Université Paris Cité, Paris, France
- Service de Gynécologie-Obstétrique, AP-HP Hôpital Universitaire Necker-Enfants Malades, Paris, France
| | - J-M Jouannic
- Département de Médecine Fœtale, Pôle ORIGYNE.6, AP-HP Hôpital Armand Trousseau, Paris, France
- Université Sorbonne Paris Cité, Paris, France
| | - O Picone
- Service de Gynécologie-Obstétrique, AP-HP Hôpital Louis Mourier, Colombes, France
- Université Paris Diderot, INSERM UMR1137, IAME, Paris, France
| | - L Carbillon
- Service de Gynécologie-Obstétrique, AP-HP Hôpital Jean-Verdier, Bondy, France
- Université Paris 13, Bobigny, France
| | - F Vialard
- Service de Cytogénétique, CHI Poissy-Saint Germain en Laye, Poissy, France
| | - E Launay
- Service de Cytogénétique et Biologie Cellulaire, CHU Rennes, Rennes, France
| | - V Tsatsaris
- UR 7537 BioSTM, UFR de Pharmacie, Faculté de Santé, Université Paris Cité, Paris, France
| | - E Curis
- UR 7537 BioSTM, UFR de Pharmacie, Faculté de Santé, Université Paris Cité, Paris, France
- Laboratoire d'Hématologie, Hôpital Lariboisière, AP-HP.nord, Paris, France
| | - L El Khattabi
- Plateforme de Dépistage Prénatal Non Invasif par Analyse de l'ADN Libre Circulant, AP-HP, Hôpital Cochin and Université Paris Cité, Paris, France
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute (ICM), Inserm, CNRS, Hôpital Pitié Salpêtrière, Paris, France
- Unité de Génomique Chromosomique, Département de Génétique Médicale, APHP, Hôpitaux Armand Trousseau et Pitié-Salpêtrière, Paris Brain Institute - ICM, Sorbonne Université, Paris, France
| |
Collapse
|
5
|
Laššáková S, Šenkyřík P, Pazourková E, Hořínek A, Calda P, Břešťák M, Světnicová K, Neužil P, Korabečná M. Rapid non-invasive prenatal screening test for trisomy 21 based on digital droplet PCR. Sci Rep 2023; 13:22948. [PMID: 38135736 PMCID: PMC10746715 DOI: 10.1038/s41598-023-50330-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 12/19/2023] [Indexed: 12/24/2023] Open
Abstract
Non-invasive prenatal tests for the detection of fetal aneuploidies are predominantly based on the analysis of cell-free DNA (cfDNA) from the plasma of pregnant women by next-generation sequencing. The development of alternative tests for routine genetic laboratories is therefore desirable. Multiplex digital droplet PCR was used to detect 16 amplicons from chromosome 21 and 16 amplicons from chromosome 18 as the reference. Two fluorescently labeled lock nucleic acid probes were used for the detection of reaction products. The required accuracy was achieved by examining 12 chips from each patient using Stilla technology. The plasma cfDNA of 26 pregnant women with euploid pregnancies and 16 plasma samples from pregnancies with trisomy 21 were analyzed to determine the cutoff value for sample classification. The test was validated in a blind study on 30 plasma samples from pregnant patients with a risk for trisomy 21 ranging from 1:4 to 1:801. The results were in complete agreement with the results of the invasive diagnostic procedure (sensitivity, specificity, PPV, and NPV of 100%). Low cost, and speed of analysis make it a potential screening method for implementation into the clinical workflow to support the combined biochemical and ultrasound results indicating a high risk for trisomy 21.
Collapse
Affiliation(s)
- Soňa Laššáková
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Albertov 4, 128 00, Prague, Czech Republic
| | - Pavel Šenkyřík
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Albertov 4, 128 00, Prague, Czech Republic
| | - Eva Pazourková
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Albertov 4, 128 00, Prague, Czech Republic
- Department of Nephrology, First Faculty of Medicine, Charles University and General University Hospital in Prague, U Nemocnice 499/2, 128 08, Prague 2, Czech Republic
| | - Aleš Hořínek
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Albertov 4, 128 00, Prague, Czech Republic
- 3rd Department of Internal Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, U Nemocnice 1, 128 08, Prague 1, Czech Republic
| | - Pavel Calda
- Department of Gynaecology, Obstetrics and Neonatology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Apolinarska 18, 128 51, Prague, Czech Republic
| | - Miroslav Břešťák
- Department of Gynaecology, Obstetrics and Neonatology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Apolinarska 18, 128 51, Prague, Czech Republic
- Prenatal Diagnosis Center ProfiG2 S.R.O., Vajgarská, 1141, Prague, Czech Republic
| | | | - Pavel Neužil
- Department of Microsystem Engineering, School of Mechanical Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072, Shaanxi, People's Republic of China
| | - Marie Korabečná
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Albertov 4, 128 00, Prague, Czech Republic.
- Department of Laboratory Medicine, Faculty of Health Care and Social Work, University of Trnava in Trnava, Universitne Namestie 1, 918 43, Trnava, Slovak Republic.
| |
Collapse
|
6
|
Benn P, Cuckle H. Overview of Noninvasive Prenatal Testing (NIPT) for the Detection of Fetal Chromosome Abnormalities; Differences in Laboratory Methods and Scope of Testing. Clin Obstet Gynecol 2023; 66:536-556. [PMID: 37650667 DOI: 10.1097/grf.0000000000000803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Although nearly all noninvasive prenatal testing is currently based on analyzing circulating maternal cell-free DNA, the technical methods usedvary considerably. We review the different methods. Based on validation trials and clinical experience, there are mostly relatively small differences in screening performance for trisomies 21, 18, and 13 in singleton pregnancies. Recent reports show low no-call rates for all methods, diminishing its importance when choosing a laboratory. However, method can be an important consideration for twin pregnancies, screening for sex chromosome abnormalities, microdeletion syndromes, triploidy, molar pregnancies, rare autosomal trisomies, and segmental imbalances, and detecting maternal chromosome abnormalities.
Collapse
Affiliation(s)
- Peter Benn
- Department of Obstetrics and Gynecology, University of Connecticut Health Center, Farmington, Connecticut
| | - Howard Cuckle
- Department of Obstetrics and Gynecology, Faculty of Medicine, Tel Aviv University, Israel
| |
Collapse
|
7
|
Dunn TM, Subramaniam A. Updates in Genetic Screening for the General Obstetrician. Obstet Gynecol Clin North Am 2023; 50:493-507. [PMID: 37500212 DOI: 10.1016/j.ogc.2023.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The number of prenatal genetic screening options, including aneuploidy screening and carrier screening, has drastically increased with rapid advancements in DNA sequencing technologies. Noninvasive prenatal screening analyzing cell-free DNA has quickly been integrated into routine prenatal care as it is the most sensitive and specific screening method for pregnancies at increased and average risk of fetal aneuploidy. The aim of this article is to outline current recommendations for cell-free DNA screening and carrier screening, important aspects of pretest and posttest counseling for obstetric providers, and which patients should be referred to a genetic specialist.
Collapse
Affiliation(s)
- Taylor M Dunn
- Department of Genetics, University of Alabama at Birmingham, 1720 2nd Avenue South, VH1L108B, Birmingham, AL 35294-0019, USA.
| | - Akila Subramaniam
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Alabama at Birmingham, 1700 6th Avenue South, Women and Infants Center, 10270, Birmingham, AL 35249, USA
| |
Collapse
|
8
|
Demko Z, Prigmore B, Benn P. A Critical Evaluation of Validation and Clinical Experience Studies in Non-Invasive Prenatal Testing for Trisomies 21, 18, and 13 and Monosomy X. J Clin Med 2022; 11:jcm11164760. [PMID: 36012999 PMCID: PMC9410356 DOI: 10.3390/jcm11164760] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/28/2022] [Accepted: 08/11/2022] [Indexed: 11/25/2022] Open
Abstract
Non-invasive prenatal testing (NIPT) for trisomies 21, 18, 13 and monosomy X is widely utilized with massively parallel shotgun sequencing (MPSS), digital analysis of selected regions (DANSR), and single nucleotide polymorphism (SNP) analyses being the most widely reported methods. We searched the literature to find all NIPT clinical validation and clinical experience studies between January 2011 and January 2022. Meta-analyses were performed using bivariate random-effects and univariate regression models for estimating summary performance measures across studies. Bivariate meta-regression was performed to explore the influence of testing method and study design. Subgroup and sensitivity analyses evaluated factors that may have led to heterogeneity. Based on 55 validation studies, the detection rate (DR) was significantly higher for retrospective studies, while the false positive rate (FPR) was significantly lower for prospective studies. Comparing the performance of NIPT methods for trisomies 21, 18, and 13 combined, the SNP method had a higher DR and lower FPR than other methods, significantly so for MPSS, though not for DANSR. The performance of the different methods in the 84 clinical experience studies was consistent with validation studies. Clinical positive predictive values of all NIPT methods improved over the last decade. We conclude that all NIPT methods are highly effective for fetal aneuploidy screening, with performance differences across methodologies.
Collapse
Affiliation(s)
| | | | - Peter Benn
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT 06030, USA
- Correspondence:
| |
Collapse
|
9
|
Genovese G, Mello CJ, Loh PR, Handsaker RE, Kashin S, Whelan CW, Bayer-Zwirello LA, McCarroll SA. Chromosomal phase improves aneuploidy detection in non-invasive prenatal testing at low fetal DNA fractions. Sci Rep 2022; 12:12025. [PMID: 35835769 PMCID: PMC9283487 DOI: 10.1038/s41598-022-14049-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/31/2022] [Indexed: 11/09/2022] Open
Abstract
Non-invasive prenatal testing (NIPT) to detect fetal aneuploidy by sequencing the cell-free DNA (cfDNA) in maternal plasma is being broadly adopted. To detect fetal aneuploidies from maternal plasma, where fetal DNA is mixed with far-larger amounts of maternal DNA, NIPT requires a minimum fraction of the circulating cfDNA to be of placental origin, a level which is usually attained beginning at 10 weeks gestational age. We present an approach that leverages the arrangement of alleles along homologous chromosomes—also known as chromosomal phase—to make NIPT analyses more conclusive. We validate our approach with in silico simulations, then re-analyze data from a pregnant mother who, due to a fetal DNA fraction of 3.4%, received an inconclusive aneuploidy determination through NIPT. We find that the presence of a trisomy 18 fetus can be conclusively inferred from the patient’s same molecular data when chromosomal phase is incorporated into the analysis. Key to the effectiveness of our approach is the ability of homologous chromosomes to act as natural controls for each other and the ability of chromosomal phase to integrate subtle quantitative signals across very many sequence variants. These results show that chromosomal phase increases the sensitivity of a common laboratory test, an idea that could also advance cfDNA analyses for cancer detection.
Collapse
Affiliation(s)
- Giulio Genovese
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA. .,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA. .,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA.
| | - Curtis J Mello
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Po-Ru Loh
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Robert E Handsaker
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Seva Kashin
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Christopher W Whelan
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Lucy A Bayer-Zwirello
- Steward St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA, 02135, USA
| | - Steven A McCarroll
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| |
Collapse
|
10
|
Kantor V, Jelsema R, Xu W, DiNonno W, Young K, Demko Z, Benn P. Non‐invasive prenatal screening for fetal triploidy using single nucleotide polymorphism (SNP)‐based testing: Differential Diagnosis And Clinical Management In Cases Showing An Extra Haplotype. Prenat Diagn 2022; 42:994-999. [PMID: 35574995 PMCID: PMC9539994 DOI: 10.1002/pd.6169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/06/2022] [Accepted: 05/11/2022] [Indexed: 12/02/2022]
Abstract
Objective An extra haplotype is infrequently encountered in single nucleotide polymorphism(SNP)‐based non‐invasive prenatal testing (NIPT) and is usually attributed to an undetected twin or triploidy. We reviewed a large series to establish relative frequencies of these outcomes and identify alternative causes. Methods In 515,804 women receiving NIPT from September 2017 through March 2019, all results with an extra haplotype were reviewed. Known viable and vanished twin pregnancies were excluded. For positive cases, pregnancy outcome information was sought. Results Of 1005 results with an extra haplotype (1 in 513), pregnancy outcome was available for 773 cases: 11% were confirmed or suspected triploidy; 65% to vanished twin; 10% with pregnancy loss. Rare explanations included complete mole, chimera, undisclosed donor egg pregnancy, maternal organ transplant and one instance of maternal neoplasm. Among triploid cases that were detected and independently confirmed, 23/27 (85%) were diandric. Conclusion SNP‐based NIPT, with detection of an extra haplotype, is 11% predictive of triploidy. For results with an extra haplotype, ultrasound is recommended to establish viability, evaluate for twins (viable or vanished), and detect findings consistent with triploidy. Review of patient history, serum screening, and ultrasound will reduce the number of CVS or amniocenteses necessary to confirm a diagnosis of triploidy.
What's already known about this topic?
Both digynic and diandric triploidy are occasionally seen in pregnancies but are extremely rare in live‐births In cell‐free DNA prenatal screening, the presence of an extra haplotype could be indicative of either twin pregnancy or triploidy
What does this study add?
Outcomes for a large series of prenatal screening tests where an extra haplotype was identified in cell‐free DNA Complete moles, chimeras, transplantation, and donor egg are additional explanations for extra haplotypes We discuss prenatal management when an extra haplotype is observed in cell‐free DNA
Collapse
Affiliation(s)
| | | | | | | | | | | | - Peter Benn
- Department of Genetics and Genome Sciences UConn Health Farmington San Carlos CT USA
| |
Collapse
|
11
|
Liu Y, Cheng L, Wang G, Lv J, He Y, Shao PL, Hu R, Xiao H, Tang J, Niu D, Yang J, Tang Z, Xu Z, Liu Y, Li Y, Song K, Wu B, Zhang B. A nano-magnetic size selective cfDNA extraction platform for liquid biopsy with enhanced precision. J Chromatogr B Analyt Technol Biomed Life Sci 2022; 1199:123236. [DOI: 10.1016/j.jchromb.2022.123236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/22/2022] [Accepted: 03/29/2022] [Indexed: 10/18/2022]
|
12
|
Wang EY, Perni UC, Gregg AR. Genetic Screening and Teratogenic Exposures: Considerations in Caring for the Uterus Transplant Patient. Clin Obstet Gynecol 2022; 65:76-83. [PMID: 35045028 DOI: 10.1097/grf.0000000000000677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Counseling the uterus transplant patient requires an enhanced knowledge of unique genetic challenges that include an understanding of the spectrum of Mayer-Rokitansky-Küster-Hauser syndrome. Patients should understand their options for genetic screening and testing including preimplantation genetic testing for aneuploidy, genetic screening, and diagnostic testing. This patient population is potentially at risk for fetal anomalies due to the increased susceptibility to infections, such as cytomegalovirus. There are management strategies to minimize this risk. The risk of teratogenicity from mycophenolate is eliminated by a washout period before embryo transfer.
Collapse
Affiliation(s)
- Eileen Y Wang
- Division of Maternal-Fetal Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Uma C Perni
- Women's Health Institute, Division of Maternal-Fetal Medicine, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Anthony R Gregg
- Department of Obstetrics and Gynecology, Prisma Health, Columbia, South Carolina
| |
Collapse
|
13
|
Dar P, Jacobsson B, MacPherson C, Egbert M, Malone F, Wapner RJ, Roman AS, Khalil A, Faro R, Madankumar R, Edwards L, Haeri S, Silver R, Vohra N, Hyett J, Clunie G, Demko Z, Martin K, Rabinowitz M, Flood K, Carlsson Y, Doulaveris G, Malone C, Hallingstrom M, Klugman S, Clifton R, Kao C, Hakonarson H, Norton ME. Cell-free DNA screening for trisomies 21, 18, and 13 in pregnancies at low and high risk for aneuploidy with genetic confirmation. Am J Obstet Gynecol 2022; 227:259.e1-259.e14. [PMID: 35085538 DOI: 10.1016/j.ajog.2022.01.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 11/17/2022]
Abstract
BACKGROUND Cell-free DNA noninvasive prenatal screening for trisomies 21, 18, and 13 has been rapidly adopted into clinical practice. However, previous studies are limited by a lack of follow-up genetic testing to confirm the outcomes and accurately assess test performance, particularly in women at a low risk for aneuploidy. OBJECTIVE To measure and compare the performance of cell-free DNA screening for trisomies 21, 18, and 13 between women at a low and high risk for aneuploidy in a large, prospective cohort with genetic confirmation of results STUDY DESIGN: This was a multicenter prospective observational study at 21 centers in 6 countries. Women who had single-nucleotide-polymorphism-based cell-free DNA screening for trisomies 21, 18, and 13 were enrolled. Genetic confirmation was obtained from prenatal or newborn DNA samples. The test performance and test failure (no-call) rates were assessed for the cohort, and women with low and high previous risks for aneuploidy were compared. An updated cell-free DNA algorithm blinded to the pregnancy outcome was also assessed. RESULTS A total of 20,194 women were enrolled at a median gestational age of 12.6 weeks (interquartile range, 11.6-13.9). The genetic outcomes were confirmed in 17,851 cases (88.4%): 13,043 (73.1%) low-risk and 4808 (26.9%) high-risk cases for aneuploidy. Overall, 133 trisomies were diagnosed (100 trisomy 21; 18 trisomy 18; 15 trisomy 13). The cell-free DNA screen positive rate was lower in the low-risk vs the high-risk group (0.27% vs 2.2%; P<.0001). The sensitivity and specificity were similar between the groups. The positive predictive value for the low- and high-risk groups was 85.7% vs 97.5%; P=.058 for trisomy 21; 50.0% vs 81.3%; P=.283 for trisomy 18; and 62.5% vs 83.3; P=.58 for trisomy 13, respectively. Overall, 602 (3.4%) patients had no-call result after the first draw and 287 (1.61%) after including cases with a second draw. The trisomy rate was higher in the 287 cases with no-call results than patients with a result on a first draw (2.8% vs 0.7%; P=.001). The updated algorithm showed similar sensitivity and specificity to the study algorithm with a lower no-call rate. CONCLUSION In women at a low risk for aneuploidy, single-nucleotide-polymorphism-based cell-free DNA has high sensitivity and specificity, positive predictive value of 85.7% for trisomy 21 and 74.3% for the 3 common trisomies. Patients who receive a no-call result are at an increased risk of aneuploidy and require additional investigation.
Collapse
Affiliation(s)
- Pe'er Dar
- Department of Obstetrics and Gynecology and Women's Health, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY.
| | - Bo Jacobsson
- Department of Obstetrics and Gynecology, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Cora MacPherson
- The Biostatistics Center, George Washington University, Washington, DC
| | | | - Fergal Malone
- Department of Obstetrics and Gynecology, Rotunda Hospital, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Ronald J Wapner
- Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, NY
| | - Ashley S Roman
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY
| | - Asma Khalil
- Department of Obstetrics and Gynecology, St George's Hospital, University of London, London, United Kingdom
| | - Revital Faro
- Department of Obstetrics and Gynecology, St. Peter's University Hospital, New Brunswick, NJ
| | - Rajeevi Madankumar
- Department of Obstetrics and Gynecology, Long Island Jewish Medical Center, Hyde Park, NY
| | | | - Sina Haeri
- Austin Maternal-Fetal Medicine, Austin, TX
| | - Robert Silver
- Department of Obstetrics and Gynecology, University of Utah, Salt Lake City, UT
| | - Nidhi Vohra
- Department of Obstetrics and Gynecology, North Shore University Hospital, Manhasset, NY
| | - Jon Hyett
- Department of Obstetrics and Gynecology, Royal Prince Alfred Hospital, University of Sydney, Camperdown, Australia
| | - Garfield Clunie
- Department of Obstetrics and Gynecology, Icahn School of Medicine at Mount Sinai, New York, NY
| | | | | | | | - Karen Flood
- Department of Obstetrics and Gynecology, Rotunda Hospital, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Ylva Carlsson
- Department of Obstetrics and Gynecology, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Georgios Doulaveris
- Department of Obstetrics and Gynecology and Women's Health, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY
| | - Ciara Malone
- Department of Obstetrics and Gynecology, Rotunda Hospital, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Maria Hallingstrom
- Department of Obstetrics and Gynecology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Susan Klugman
- Department of Obstetrics and Gynecology and Women's Health, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY
| | - Rebecca Clifton
- The Biostatistics Center, George Washington University, Washington, DC
| | - Charlly Kao
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Hakon Hakonarson
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Mary E Norton
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California San Francisco, San Francisco, CA
| |
Collapse
|
14
|
Gug C, Mozos I, Ratiu A, Tudor A, Gorduza EV, Caba L, Gug M, Cojocariu C, Furau C, Furau G, Vaida MA, Stoicanescu D. Genetic Counseling and Management: The First Study to Report NIPT Findings in a Romanian Population. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58010079. [PMID: 35056387 PMCID: PMC8777823 DOI: 10.3390/medicina58010079] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 12/18/2021] [Accepted: 12/30/2021] [Indexed: 04/25/2023]
Abstract
Background and Objectives: Non-invasive prenatal testing (NIPT) has been confirmed as the most accurate screening test for trisomies 21, 18, 13, sex chromosomes aneuploidies and several microdeletions. This study aimed to assess the accuracy of cell free DNA testing based on low-level whole-genome sequencing to screen for these chromosomal abnormalities and to evaluate the clinical performance of NIPT. Materials and Methods: 380 consecutive cases from a single genetic center, from Western Romania were included in this retrospective study. Cell-free nucleic acid extraction from maternal blood, DNA sequencing and analysis of sequenced regions were performed by BGI Hong Kong and Invitae USA to determine the risk of specific fetal chromosomal abnormalities. In high-risk cases the results were checked by direct analysis of fetal cells obtained by invasive methods: 6 chorionic villus sampling and 10 amniocenteses followed by combinations of QF-PCR, karyotyping and aCGH. Results: NIPT results indicated low risk in 95.76% of cases and high risk in 4.23%. Seven aneuploidies and one microdeletion were confirmed, the other results were found to be a false-positive. A gestational age of up to 22 weeks had no influence on fetal fraction. There were no significant differences in fetal fraction across the high and low risk groups. Conclusions: This is the first study in Romania to report the NIPT results. The confirmation rate was higher for autosomal aneuploidies compared to sex chromosome aneuploidies and microdeletions. All cases at risk for trisomy 21 were confirmed. Only one large fetal microdeletion detected by NIPT has been confirmed. False positive NIPT results, not confirmed by invasive methods, led to the decision to continue the pregnancy. The main limitation of the study is the small number of patients included. NIPT can be used as a screening method for all pregnancies, but in high-risk cases, an invasive confirmation test was performed.
Collapse
Affiliation(s)
- Cristina Gug
- Department of Microscopic Morphology, “Victor Babeş” University of Medicine and Pharmacy, 300041 Timisoara, Romania; (C.G.); (D.S.)
| | - Ioana Mozos
- Department of Functional Sciences, Discipline of Pathophysiology, “Victor Babes” University of Medicine and Pharmacy, 300173 Timisoara, Romania
- Center for Translational Research and Systems Medicine, “Victor Babes” University of Medicine and Pharmacy, 300173 Timisoara, Romania
- Correspondence: ; Tel.: +40-745610004
| | - Adrian Ratiu
- Department of Obstetrics and Gynecology II, “Victor Babes” University of Medicine and Pharmacy, 300041 Timisoara, Romania;
- Obstetrics-Gynecology Clinic IV, Municipal Emergency Clinical Hospital, 300231 Timisoara, Romania
| | - Anca Tudor
- Department of Functional Sciences, Discipline of Medical Informatics and Biostatistics, “Victor Babes” University of Medicine and Pharmacy, 300041 Timisoara, Romania;
| | - Eusebiu Vlad Gorduza
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (E.V.G.); (L.C.)
| | - Lavinia Caba
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (E.V.G.); (L.C.)
| | - Miruna Gug
- Faculty of Medicine, “Victor Babeş” University of Medicine and Pharmacy, 300041 Timisoara, Romania; (M.G.); (C.C.)
| | - Catalina Cojocariu
- Faculty of Medicine, “Victor Babeş” University of Medicine and Pharmacy, 300041 Timisoara, Romania; (M.G.); (C.C.)
| | - Cristian Furau
- Life Sciences Department, Faculty of Medicine, “Vasile Goldis“ Western University of Arad, 310414 Arad, Romania;
| | - Gheorghe Furau
- General Medicine Department, Faculty of Medicine, “Vasile Goldis“ Western University of Arad, 310414 Arad, Romania;
| | - Monica Adriana Vaida
- Department of Anatomy and Embryology, “Victor Babes” University of Medicine and Pharmacy, 300041 Timisoara, Romania;
| | - Dorina Stoicanescu
- Department of Microscopic Morphology, “Victor Babeş” University of Medicine and Pharmacy, 300041 Timisoara, Romania; (C.G.); (D.S.)
| |
Collapse
|
15
|
Lugthart MA, Bet BB, Elsman F, van de Kamp K, de Bakker BS, Linskens IH, van Maarle MC, van Leeuwen E, Pajkrt E. Increased nuchal translucency before 11 weeks of gestation: Reason for referral? Prenat Diagn 2021; 41:1685-1693. [PMID: 34592002 PMCID: PMC9293299 DOI: 10.1002/pd.6054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/20/2021] [Accepted: 09/21/2021] [Indexed: 11/09/2022]
Abstract
OBJECTIVES In this era of non-invasive-prenatal testing (NIPT), when dating scans are usually performed around 10 weeks of gestation, an increased NT before the official established timeframe (CRL between 45 and 84 mm) may be encountered. Information on management of these pregnancies is limited. Therefore, we evaluated the relationship between an early increased NT and adverse pregnancy outcome. Secondary, we evaluated the rate of chromosomal anomalies that might have been missed in first trimester should solely NIPT be performed as first-tier test, and the rate of adverse pregnancy outcome if NT normalizes before 14 weeks. METHODS We performed a retrospective cohort study that included all pregnancies between January 1, 2007 and June 1, 2020 in Amsterdam UMC locations AMC and VUmc. We included fetuses with a crown-rump length (CRL) < 45 mm (∼11 weeks) and a nuchal translucency (NT) measurement ≥2.5 mm. Fetuses referred with an early increased NT and a major fetal anomaly at the dating scan were excluded, as were cases of parents with a family history of monogenetic disease(s) or recognized carriers of a balanced translocation. RESULTS We included 120 fetuses of which 66.7% (80/120) had an adverse pregnancy outcome. Congenital anomalies were present in 56.7% (68/120), 45.8% (55/120) had a chromosomal anomaly. The prevalence of congenital anomalies was 30.3% in fetuses with NT 2.5-3.4 mm compared to 66.7% with NT ≥ 3.5 mm (p < 0.001). 16.7% (20/120) had a chromosomal anomaly that might have been missed by conventional NIPT in first trimester. We found an adverse pregnancy outcome of 24% in the group with a normalized NT compared to 78.1% in the group with a persistently increased NT (p < 0.001). CONCLUSION An early increased NT should make the sonographer alert. In this selected cohort, an early increased NT was associated with a high probability of having an adverse pregnancy outcome. Regardless of CRL, we deem that an early increased NT ≥ 3.5 mm warrants referral to a Fetal Medicine Unit for an extensive work-up. NT normalization seems favorable, but a prospective study should define the appropriate work-up for NT in the lower range (2.5-3.4 mm).
Collapse
Affiliation(s)
- Malou A Lugthart
- Department of Obstetrics, Amsterdam Reproduction and Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Bo B Bet
- Department of Obstetrics, Amsterdam Reproduction and Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Fleur Elsman
- Department of Obstetrics, Amsterdam Reproduction and Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Karline van de Kamp
- Department of Obstetrics, Amsterdam Reproduction and Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Bernadette S de Bakker
- Department of Medical Biology, Section Clinical Anatomy & Embryology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Ingeborg H Linskens
- Department of Obstetrics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Merel C van Maarle
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Elisabeth van Leeuwen
- Department of Obstetrics, Amsterdam Reproduction and Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Eva Pajkrt
- Department of Obstetrics, Amsterdam Reproduction and Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
16
|
Bajka A, Bajka M, Chablais F, Burkhardt T. Audit of the first > 7500 noninvasive prenatal aneuploidy tests in a Swiss genetics center. Arch Gynecol Obstet 2021; 305:1185-1192. [PMID: 34533609 PMCID: PMC9013335 DOI: 10.1007/s00404-021-06203-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 08/20/2021] [Indexed: 11/29/2022]
Abstract
Objectives Noninvasive prenatal testing (NIPT) is actually the most accurate method of screening for fetal chromosomal aberration (FCA). We used pregnancy outcome record to evaluate a complete data set of single nucleotide polymorphism-based test results performed by a Swiss genetics center. Materials and methods The Panorama® test assesses the risk of fetal trisomies (21, 18 and 13), gonosomal aneuploidy (GAN), triploidy or vanishing twins (VTT) and five different microdeletions (MD). We evaluated all 7549 test results meeting legal and quality requirements taken in women with nondonor singleton pregnancies between April 2013 and September 2016 classifying them as high or low risk. Follow-up ended after 9 months, data collection 7 months later. Results The Panorama® test provided conclusive results in 96.1% of cases, detecting 153 FCA: T21 n = 76, T18 n = 19, T13 n = 15, GAN n = 19, VTT n = 13 and MD n = 11 (overall prevalence 2.0%). Pregnancy outcome record was available for 68.6% of conclusive laboratory results, including 2.0% high-risk cases. In this cohort the Panorama® test exhibited 99.90% sensitivity for each trisomy; specificity was 99.90% for T21, 99.98% for T18 and 99.94% for T13. False positive rate was 0.10% for T21, 0.02% for T18 and 0.06% for T13. Conclusion SNP-based testing by a Swiss genetics center confirms the expected accuracy of NIPT in FCA detection.
Collapse
Affiliation(s)
- Anahita Bajka
- Department of Obstetrics, University Hospital Zurich, Frauenklinikstr. 10, 8091, Zurich, Switzerland
| | - Michael Bajka
- Department of Gynecology, University Hospital of Zurich, Zurich, Switzerland
| | - Fabian Chablais
- Genetica, Human Genetics and Genetic Counselling Unit, 8001, Zurich, Switzerland
| | - Tilo Burkhardt
- Department of Obstetrics, University Hospital Zurich, Frauenklinikstr. 10, 8091, Zurich, Switzerland.
| |
Collapse
|
17
|
Benn P, Rebarber A. Non-invasive prenatal testing in the management of twin pregnancies. Prenat Diagn 2021; 41:1233-1240. [PMID: 34170028 PMCID: PMC8518532 DOI: 10.1002/pd.5989] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 12/02/2022]
Abstract
Twin pregnancies are common and associated with pregnancy complications and adverse outcomes. Prenatal clinical management is intensive and has been hampered by inferior screening and less acceptable invasive testing. For aneuploidy screening, meta‐analyses show that non‐invasive prenatal testing (NIPT) through analysis of cell‐free DNA (cf‐DNA) is superior to serum and ultrasound‐based tests. The positive predictive value for NIPT is driven strongly by the discriminatory power of the assay and only secondarily by the prior risk. Uncertainties in a priori risks for aneuploidies in twin pregnancies are therefore of lesser importance with NIPT. Additional information on zygosity can be obtained using NIPT. Establishing zygosity can be helpful when chorionicity was not reliably established early in pregnancy or where the there is a concern for one versus two affected fetuses. In dizygotic twin pregnancies, individual fetal fractions can be measured to ensure that both values are satisfactory. Vanishing twins can be identified by NIPT. Although clinical utility of routinely detecting vanishing twins has not yet been demonstrated, there are individual cases where cf‐DNA analysis could be helpful in explaining unusual clinical or laboratory observations. We conclude that cf‐DNA analysis and ultrasound have synergistic roles in the management of multiple gestational pregnancies.
What's already known about this topic?
In singleton pregnancies, non‐invasive prenatal testing (NIPT) for fetal aneuploidy is more effective than conventional serum and ultrasound‐based screening tests. NIPT is more complex in dizygotic twin pregnancies due to the presence of two fetal genotypes. Overall fetal fraction is higher in twin pregnancies but the individual contribution for each fetus is lower.
What does this study add?
A review of cell‐free DNA testing in twin pregnancies. Individual fetal fractions in dizygotic twin pregnancies can be measured. Zygosity can be established using NIPT and this can be particularly useful when there are concerns about chorionicity or determining whether one versus two fetuses are affected. Vanishing twins can be detected through NIPT and this testing could be considered for some apparently singleton pregnancies with complications.
Collapse
Affiliation(s)
- Peter Benn
- Department of Genetics and Genome Sciences, UConn Health, Farmington, Connecticut, USA
| | - Andrei Rebarber
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Division of Maternal Fetal Medicine, Englewood Hospital, Englewood, New Jersey, USA
| |
Collapse
|
18
|
Liu S, Liu H, Liu J, Bai T, Jing X, Xia T, Deng C, Liu Y, Cheng J, Wei X, Xing L, Luo Y, Zhou Q, Zhu Q. Follow-up in Patients With Non-invasive Prenatal Screening Failures: A Reflection on the Choice of Further Prenatal Diagnosis. Front Genet 2021; 12:666648. [PMID: 34093659 PMCID: PMC8172122 DOI: 10.3389/fgene.2021.666648] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
Background Our aim was to provide a theoretical basis for clinicians to conduct genetic counseling and choose further prenatal diagnosis methods for pregnant women who failed non-invasive prenatal screening (NIPS). Methods A retrospective analysis was performed on pregnant women who had failed NIPS tests. Results Among the 123,291 samples, 394 pregnant women did not obtain valid results due to test failures. A total of 378 pregnant women were available for follow-up, while 16 patients were lost to follow-up. Of these 378, 135 pregnant women chose further prenatal diagnosis through amniocentesis, and one case of dysplasia was recalled for postpartum chromosome testing. The incidence rate of congenital chromosomal abnormalities in those who failed the NIPS was 3.97% (15/378), which was higher than that of the chromosomal abnormalities in the common population (1.8%). Among the pregnant women who received prenatal diagnosis, the positive rates of chromosomal abnormalities in the chromosomal microarray analysis/copy number variation sequencing (CMA/CNV-seq) group and in the karyotyping group were 15.28 and 4.76%, respectively. Conclusion Prenatal diagnosis should be strongly recommended in posttest genetic counseling for pregnant women with NIPS failures. Further, high-resolution detection methods should be recommended for additional prenatal diagnoses.
Collapse
Affiliation(s)
- Sha Liu
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Hongqian Liu
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Jianlong Liu
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Ting Bai
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Xiaosha Jing
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Tianyu Xia
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Cechuan Deng
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Yunyun Liu
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Jing Cheng
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Xiang Wei
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Lingling Xing
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Yuan Luo
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Quanfang Zhou
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| | - Qian Zhu
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, China
| |
Collapse
|
19
|
Zhang B, Zhao S, Wan H, Liu Y, Zhang F, Guo X, Zeng W, Zhang H, Zeng L, Qu J, Wu BQ, Wan X, Cantor CR, Ge D. High-resolution DNA size enrichment using a magnetic nano-platform and application in non-invasive prenatal testing. Analyst 2021; 145:5733-5739. [PMID: 32748914 DOI: 10.1039/d0an00813c] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Precise DNA sizing can boost sequencing efficiency, reduce cost, improve data quality, and even allow sequencing of low-input samples, while current pervasive DNA sizing approaches are incapable of differentiating DNA fragments under 200 bp with high resolution (<20 bp). In non-invasive prenatal testing (NIPT), the size distribution of cell-free fetal DNA in maternal plasma (main peak at 143 bp) is significantly different from that of maternal cell-free DNA (main peak at 166 bp). The current pervasive workflow of NIPT and DNA sizing is unable to take advantage of this 20 bp difference, resulting in sample rejection, test inaccuracy, and restricted clinical utility. Here we report a simple, automatable, high-resolution DNA size enrichment workflow, named MiniEnrich, on a magnetic nano-platform to exploit this 20 bp size difference and to enrich fetal DNA fragments from maternal blood. Two types of magnetic nanoparticles were developed, with one able to filter high-molecular-weight DNA with high resolution and the other able to recover the remaining DNA fragments under the size threshold of interest with >95% yield. Using this method, the average fetal fraction was increased from 13% to 20% after the enrichment, as measured by plasma DNA sequencing. This approach provides a new tool for high-resolution DNA size enrichment under 200 bp, which may improve NIPT accuracy by rescuing rejected non-reportable clinical samples, and enable NIPT earlier in pregnancy. It also has the potential to improve non-invasive screening for fetal monogenic disorders, differentiate tumor-related DNA in liquid biopsy and find more applications in autoimmune disease diagnosis.
Collapse
Affiliation(s)
- Bo Zhang
- Apostle Inc., San Jose, CA 95134, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
For decades, prenatal testing has been offered to evaluate pregnancies for genetic conditions. In recent years, the number of testing options and range of testing capabilities has dramatically increased. Because of the risks associated with invasive diagnostic testing, research has focused on the detection of genetic conditions through screening technologies such as cell-free DNA. Screening for aneuploidy, copy number variants, and monogenic disorders is clinically available using a sample of maternal blood, but limited data exist on the accuracy of some of these testing options. Additional research is needed to examine the accuracy and utility of screening for increasingly rare conditions. As the breadth of prenatal genetic testing options continues to expand, patients, clinical providers, laboratories, and researchers need to find collaborative means to validate and introduce new testing technologies responsibly. Adequate validation of prenatal tests and effective integration of emerging technologies into prenatal care will become even more important once prenatal treatments for genetic conditions become available.
Collapse
Affiliation(s)
- Blair Stevens
- McGovern Medical School at UTHealth in Houston, Department of Obstetrics, Gynecology and Reproductive Sciences, Houston, Texas 77030, USA
| |
Collapse
|
21
|
Welker NC, Lee AK, Kjolby RAS, Wan HY, Theilmann MR, Jeon D, Goldberg JD, Haas KR, Muzzey D, Chu CS. High-throughput fetal fraction amplification increases analytical performance of noninvasive prenatal screening. Genet Med 2020; 23:443-450. [PMID: 33190143 PMCID: PMC7935715 DOI: 10.1038/s41436-020-01009-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/01/2020] [Accepted: 10/06/2020] [Indexed: 12/25/2022] Open
Abstract
Purpose The percentage of a maternal cell-free DNA (cfDNA) sample that is fetal-derived (the fetal fraction; FF) is a key driver of the sensitivity and specificity of noninvasive prenatal screening (NIPS). On certain NIPS platforms, >20% of women with high body mass index (and >5% overall) receive a test failure due to low FF (<4%). Methods A scalable fetal fraction amplification (FFA) technology was analytically validated on 1264 samples undergoing whole-genome sequencing (WGS)–based NIPS. All samples were tested with and without FFA. Results Zero samples had FF < 4% when screened with FFA, whereas 1 in 25 of these same patients had FF < 4% without FFA. The average increase in FF was 3.9-fold for samples with low FF (2.3-fold overall) and 99.8% had higher FF with FFA. For all abnormalities screened on NIPS, z-scores increased 2.2-fold on average in positive samples and remained unchanged in negative samples, powering an increase in NIPS sensitivity and specificity. Conclusion FFA transforms low-FF samples into high-FF samples. By combining FFA with WGS–based NIPS, a single round of NIPS can provide nearly all women with confident results about the broad range of potential fetal chromosomal abnormalities across the genome.
Collapse
Affiliation(s)
| | - Albert K Lee
- Myriad Women's Health, South San Francisco, CA, USA
| | | | - Helen Y Wan
- Myriad Women's Health, South San Francisco, CA, USA
| | | | - Diana Jeon
- Myriad Women's Health, South San Francisco, CA, USA
| | | | - Kevin R Haas
- Myriad Women's Health, South San Francisco, CA, USA
| | - Dale Muzzey
- Myriad Women's Health, South San Francisco, CA, USA.
| | | |
Collapse
|
22
|
Nunley PB, Hashmi SS, Johnson A, Ashfaq M, Farach LS, Singletary CN, Stevens BK. Exploring the predicted yield of prenatal testing by evaluating a postnatal population with structural abnormalities using a novel mathematical model. Prenat Diagn 2020; 41:354-361. [PMID: 33128384 DOI: 10.1002/pd.5858] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 08/29/2020] [Accepted: 10/19/2020] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To determine the yield of prenatal testing and screening options after identification of fetal structural abnormalities using a novel mathematical model. METHOD A retrospective chart review was conducted to collect structural abnormality and genetic testing data on infants who were evaluated postnatally by a medical geneticist. A novel mathematical model was used to determine and compare the predicted diagnostic yields of prenatal testing and screening options. RESULTS Over a quarter of patients with at least one structural abnormality (28.1%, n = 222) had a genetic aberration identified that explained their phenotype. Chromosomal microarray (CMA) had the highest predicted diagnostic yield (26.8%, P < .001). Karyotype (20.8%) had similar yields as genome wide NIPT (21.2%, P = .859) and NIPT with select copy number variants (CNVs) (17.9%, P = .184). Among individuals with an isolated structural abnormality, whole exome sequencing (25.9%) and CMA (14.9%) had the highest predicted yields. CONCLUSION This study introduces a novel mathematical model for predicting the potential yield of prenatal testing and screening options. This study provides further evidence that CMA has the highest predicted diagnostic yield in cases with structural abnormalities. Screening with expanded NIPT options shows potential for patients who decline invasive testing, but only in the setting of adequate pre-test counseling.
Collapse
Affiliation(s)
- Peyton B Nunley
- Department of Obstetrics and Gynecology, University of South Carolina School of Medicine, Columbia, South Carolina, USA.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas, USA
| | - Syed S Hashmi
- Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Anthony Johnson
- Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, Texas, USA.,Department of Obstetrics, Gynecology and Reproductive Sciences, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Myla Ashfaq
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas, USA.,Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Laura S Farach
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas, USA.,Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Claire N Singletary
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas, USA.,Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, Texas, USA.,Department of Obstetrics, Gynecology and Reproductive Sciences, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Blair K Stevens
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas, USA.,Department of Obstetrics, Gynecology and Reproductive Sciences, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, Texas, USA
| |
Collapse
|
23
|
Vakrilova L, Hitrova-Nikolova S, Bradinova I. Triploidy in a Live-Born Extremely Low Birth Weight Twin: Clinical Aspects. J Pediatr Genet 2020; 11:227-231. [DOI: 10.1055/s-0040-1716828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/17/2020] [Indexed: 10/23/2022]
Abstract
AbstractTriploidy is a rare chromosomal aberration characterized by a karyotype with 69 chromosomes. Triploid fetuses usually are miscarried in early pregnancy. We present a case of a triploid twin and a genetically unaffected co-twin, conceived through in vitro fertilization. A discordant growth was registered at 20 weeks of gestation. Cesarean section was performed at 355/7 gestational week. The second twin was extremely growth restricted female (780 g) with oligohydramnios and severe respiratory distress, and died at 20 hours of age. The autopsy revealed unilobar left lung, bilobar right lung, and cysts of the terminal bronchioles. Quantitative fluorescent polymerase chain reaction detected triploidy compatible pattern. So, early intrauterine growth restriction may be a sign of triploidy, which must be proven by pre or postnatal genetic testing.
Collapse
Affiliation(s)
- Liliya Vakrilova
- Department of Obstetrics and Gynecology, Medical University of Sofia, Sofia, Bulgaria
- Neonatology Clinic, University Hospital of Obstetrics and Gynecology “Maichin Dom,” Sofia, Bulgaria
| | - Stanislava Hitrova-Nikolova
- Department of Obstetrics and Gynecology, Medical University of Sofia, Sofia, Bulgaria
- Neonatology Clinic, University Hospital of Obstetrics and Gynecology “Maichin Dom,” Sofia, Bulgaria
| | - Irena Bradinova
- Department of Obstetrics and Gynecology, Medical University of Sofia, Sofia, Bulgaria
- National Genetic Laboratory, University Hospital of Obstetrics and Gynecology “Maichin dom,” Sofia, Bulgaria
| |
Collapse
|
24
|
Samura O. Update on noninvasive prenatal testing: A review based on current worldwide research. J Obstet Gynaecol Res 2020; 46:1246-1254. [PMID: 32558079 DOI: 10.1111/jog.14268] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 04/11/2020] [Indexed: 12/25/2022]
Abstract
Eight years have passed since noninvasive prenatal testing (NIPT) was clinically evaluated and data on NIPT for trisomy 21, 18 and 13 were collected. The data revealed that NIPT is more accurate than conventional first-trimester screening. However, there is still insufficient data regarding the clinical use of NIPT results in detecting sex chromosome aneuploidies or whole-genome regions. NIPT is already being used as a clinical screening method globally. However, it is an unconfirmed diagnostic test and the results must be interpreted with caution as they may yield false negatives, false positives or inconclusive results. Therefore, the aim of this review is to highlight the current status of information, including the different methodologies, shortcomings and implications, regarding NIPT after its adoption worldwide. It is important to include genetic counseling when implementing NIPT. Going forward, the knowledge obtained to date, including the associated shortcomings, must be considered in evaluating the effectiveness of NIPT in detecting genetic abnormalities.
Collapse
Affiliation(s)
- Osamu Samura
- Department of Obstetrics and Gynecology, Jikei University School of Medicine, Tokyo, Japan
| |
Collapse
|
25
|
Panchalee T, Poungvarin N, Amornrit W, Pooliam J, Taluengjit P, Wataganara T. Clinical performance of DNA-based prenatal screening using single-nucleotide polymorphisms approach in Thai women with singleton pregnancy. Mol Genet Genomic Med 2020; 8:e1256. [PMID: 32329244 PMCID: PMC7336763 DOI: 10.1002/mgg3.1256] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/22/2020] [Accepted: 03/24/2020] [Indexed: 12/20/2022] Open
Abstract
Background To review the performance of noninvasive prenatal screening (NIPS) using targeted single‐nucleotide polymorphisms (SNPs) approach in mixed‐risk Thai women. Methods Retrospective analysis of data for detection of trisomy 21 (T21), 18 (T18), 13 (T13), monosomy X (XO), other sex chromosome aneuploidies (SCA), and triploidy/vanishing twins (VT) from a single commercial laboratory. Results Mean (±SD) gestational age and maternal weight were 13.2 (±2.1) weeks and 125.7 (±22.4) pounds, respectively (n = 8,572). From 462/8,572 (5.4%) no‐calls; 1/462 (0.2%) was uninformative SNPs, and 1/462 chose amniocentesis. Redraw settled 323/460 (70%) samples with low fetal fraction (FF); and 8,434/8,572 (98.4%) were finally reportable, with 131 high risks (1.6%). The median (min‐max) FF of reportable (n = 8,434) and unreportable samples (n = 137) samples were 10.5% (2.6–37.9) and 3.8% (1–14.1), respectively (p < .05). Fetal karyotypes were available in 106/131 (80.9%) and 52/138 (37.7%) high risk and repeated no‐calls, respectively. The positive predictive values (PPVs) for T21 (n = 47), T18 (n = 15), T13 (n = 7), XO (n = 8), other SCA (n = 7), and triploidy/VT were 94%, 100%, 58.3%, 66.7%, 70%, and 57.1%, respectively. None of repeated no‐calls had aneuploidies. Conclusion SNP‐based NIPS has high PPVs for T21 and T18. Although the proprietary SNPs library is not population‐specific, uninformative SNPs are uncommon.
Collapse
Affiliation(s)
- Tachjaree Panchalee
- Department of Obstetrics and Gynecology, Mahidol University, Bangkok, Thailand
| | | | | | - Julaporn Pooliam
- Division of Clinical Epidemiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | | | - Tuangsit Wataganara
- Department of Obstetrics and Gynecology, Mahidol University, Bangkok, Thailand
| |
Collapse
|
26
|
Lopes JL, Lopes GS, Enninga EAL, Kearney HM, Hoppman NL, Rowsey RA. Most noninvasive prenatal screens failing due to inadequate fetal cell free DNA are negative for trisomy when repeated. Prenat Diagn 2020; 40:831-837. [PMID: 32274800 DOI: 10.1002/pd.5693] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 03/06/2020] [Accepted: 03/27/2020] [Indexed: 12/16/2022]
Abstract
OBJECTIVE We aimed to test for an association between the amount of circulating fetal cell-free DNA and trisomy, and whether NIPS failure due to low fetal fraction indicates trisomy risk. METHOD Maternal BMI, maternal age, fetal sex, gestational age, fetal cfDNA fraction, and NIPS results was collected on 2374 pregnancies. Additional clinical information was available for 1180 research consented patients. We investigated associations between fetal fraction and available variables and determined the success rate of repeat NIPS testing. RESULTS Fetal trisomy was marginally associated with decreased fetal fraction (P = .067). However, the proportions of trisomy events were not significantly increased in women who had failed NIPS due to low fetal fraction (<4%) (OR = 1.37 [0.3-7.4]; P = .714). 66% of repeated NIPS after a second blood draw were successful. CONCLUSION Failure to meet the clinical cutoff of 4% fetal fraction established for NIPS accuracy did not suggest increased risk for trisomy in our cohort. Because repeat testing was successful in the majority of cases and most failures were explained by high BMI and low gestational age, a redraw may be an appropriate next step before invasive screening due to concerns for trisomic pregnancies.
Collapse
Affiliation(s)
- Jaime L Lopes
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Guilherme S Lopes
- Department of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Hutton M Kearney
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Nicole L Hoppman
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Ross A Rowsey
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| |
Collapse
|
27
|
Juul LA, Hartwig TS, Ambye L, Sørensen S, Jørgensen FS. Noninvasive prenatal testing and maternal obesity: A review. Acta Obstet Gynecol Scand 2020; 99:744-750. [PMID: 32187653 DOI: 10.1111/aogs.13848] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/01/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022]
Abstract
Noninvasive prenatal testing (NIPT) has become a popular screening test for the most common fetal aneuploidies. The performance of NIPT is affected by several factors including maternal obesity, which results in a greater rate of no-calls for obese pregnant women. Guidelines regarding NIPT in prenatal screening have been published, but with few and divergent recommendations on the issue. We aimed to review the medical literature, guidelines from scientific societies and information material from commercial NIPT providers on no-calls and maternal obesity. We systematically identified medical literature and guidelines from scientific societies using the database MEDLINE. Information material from commercial NIPT providers was found via a systematic search on Google.com. Nine medical studies investigating the association between maternal obesity and NIPT no-calls were included. They all showed the same trend: increasing no-call rate with increasing maternal obesity. The no-call rate ranged from 0% to 4.2% for women with body mass index (BMI) 18.5-24.9 and from 5.4% to 70.1% for women BMI ≥40. We identified 17 scientific societies with guidelines and 13 commercial NIPT providers. All were checked for information material on no-calls and maternal obesity. To allow comparison, all guidelines were examined to answer the same three predefined questions. Of the 17 included scientific societies, 13 (76.5%) mentioned the association between maternal obesity and NIPT no-calls, two (11.8%) specified weight limits and three (17.6%) advised against NIPT for severely obese pregnant women. None of the 13 commercial NIPT providers provided specific recommendations, but four (30.8%) cite maternal obesity as a potential cause for a no-call. Because of the increasing number of patients in this group, we advocate updated recommendations to guide decision making in prenatal screening for obese pregnant women.
Collapse
Affiliation(s)
- Laura A Juul
- Fetal Medicine Unit, Department of Obstetrics and Gynecology, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Hvidovre Hospitals NIPT Center, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Tanja S Hartwig
- Fetal Medicine Unit, Department of Obstetrics and Gynecology, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Hvidovre Hospitals NIPT Center, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Louise Ambye
- Hvidovre Hospitals NIPT Center, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Department of Clinical Biochemistry, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Steen Sørensen
- Hvidovre Hospitals NIPT Center, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Department of Clinical Biochemistry, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Finn S Jørgensen
- Fetal Medicine Unit, Department of Obstetrics and Gynecology, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Hvidovre Hospitals NIPT Center, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
28
|
Benn P, Martin K, McKanna T, Valenti E, Billings P, Demko Z. Combining the use of a fetal fraction-based risk algorithm and probability of an informative redraw in noninvasive prenatal testing for fetal aneuploidy. J Genet Couns 2019; 29:800-806. [PMID: 31872514 PMCID: PMC7586960 DOI: 10.1002/jgc4.1208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 11/27/2019] [Accepted: 12/02/2019] [Indexed: 12/14/2022]
Abstract
Some women undergoing noninvasive prenatal testing (NIPT) do not receive an informative result due to low fetal fraction (FF). A proportion of these are at increased risk for fetal trisomy 13, 18, or triploidy, while others have no change from their prior risk. Women with an initial uninformative NIPT need to be counseled about any such change in their risk for fetal abnormality and also the probability that a redraw will be informative. To help in the decision making, we reviewed a dataset of single nucleotide polymorphism‐based NIPT with uninformative results where a redraw was received. Risk for trisomy 13, 18, or triploidy was evaluated using a fetal fraction‐based risk (FFBR) algorithm. Risk‐unchanged women were further analyzed using a regression model to determine the likelihood of an informative redraw. Of 2,644 women with an uninformative NIPT and a redraw, 1,147 (43.4%) were high risk for trisomy 13, 18, or triploidy. 1,497 (56.6%) were risk unchanged and, of these, 975 (65.1%) cases had an informative redraw (i.e., risks were available for 2,122 (80%) of those initially classified as uninformative). The regression model for the risk‐unchanged cases provided a new table for predicting an informative redraw. Likelihood of a successful redraw was significantly (p < .001) dependent on the initial FF, maternal weight, and time between blood draws. We conclude that the FFBR algorithm and the predictive model for an informative redraw provide complementary additions in the management of women presented with an initially uninformative SNP‐based NIPT due to low FF. We suggest approaches for the counseling and follow‐up testing for women with an initially uninformative NIPT.
Collapse
|
29
|
Muzzey D, Goldberg JD, Haverty C. Noninvasive prenatal screening for patients with high body mass index: Evaluating the impact of a customized whole genome sequencing workflow on sensitivity and residual risk. Prenat Diagn 2019; 40:333-341. [PMID: 31697845 PMCID: PMC7065115 DOI: 10.1002/pd.5603] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/27/2019] [Accepted: 10/15/2019] [Indexed: 12/20/2022]
Abstract
Objective Women with high body mass index (BMI) tend to have reduced fetal fraction (FF) during cell‐free DNA‐based noninvasive prenatal screening (NIPS), causing test failure rates up to 24.3% and prompting guidelines that recommend aneuploidy screening other than NIPS for patients with significant obesity. Because alternatives to NIPS are only preferable if they perform better, we compared the respective sensitivities at different BMI levels of traditional aneuploidy screening and a customized whole‐genome sequencing NIPS. Method The relationship between FF, aneuploidy, and BMI was quantified from 58 105 patients screened with a customized NIPS that does not fail samples because of low FF alone. Expected analytical sensitivity as a function of aneuploidy and BMI (eg, trisomy 18 sensitivity when BMI = 35) was determined by scaling the BMI‐ and aneuploidy‐specific FF distribution by the FF‐ and aneuploidy‐specific sensitivity calculated from empirically informed simulations. Results Across all classes of obesity and assuming zero FF‐related test failures, analytical sensitivity for the investigated NIPS exceeded that of traditional aneuploidy screening for trisomies 13, 18, and 21. Conclusion Relative to traditional aneuploidy screening, a customized NIPS with high accuracy at low FF and a low test‐failure rate is a superior screening option for women with high BMI. What's already known about this topic?
Women with high body mass index (BMI) often receive a test failure on noninvasive prenatal screening (NIPS) because of low fetal fraction (FF). The American College of Medical Genetics and Genomics recommends offering traditional aneuploidy screening to patients with “significant obesity.” NIPS offerings differ in their efficacy at low FF.
What does this study add?
Irrespective of BMI and without FF‐based test failures, it is possible for a customized NIPS to provide all women with accurate prenatal screening.
Collapse
Affiliation(s)
- Dale Muzzey
- Myriad Women's Health, South San Francisco, CA, USA.,Myriad Genetics, Salt Lake City, UT, USA
| | | | | |
Collapse
|
30
|
Hui L, Bianchi DW. Fetal fraction and noninvasive prenatal testing: What clinicians need to know. Prenat Diagn 2019; 40:155-163. [PMID: 31821597 PMCID: PMC10040212 DOI: 10.1002/pd.5620] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/15/2019] [Accepted: 11/22/2019] [Indexed: 12/20/2022]
Abstract
The fetal fraction (FF) is a function of both biological factors and bioinformatics algorithms used to interpret DNA sequencing results. It is an essential quality control component of noninvasive prenatal testing (NIPT) results. Clinicians need to understand the biological influences on FF to be able to provide optimal post-test counseling and clinical management. There are many different technologies available for the measurement of FF. Clinicians do not need to know the details behind the bioinformatics algorithms of FF measurements, but they do need to appreciate the significant variations between the different sequencing technologies used by different laboratories. There is no universal FF threshold that is applicable across all platforms and there have not been any differences demonstrated in NIPT performance by sequencing platform or method of FF calculation. Importantly, while FF should be routinely measured, there is not yet a consensus as to whether it should be routinely reported to the clinician. The clinician should know what to expect from a standard test report and whether reasons for failed NIPT results are revealed. Emerging solutions to the challenges of samples with low FF should reduce rates of failed NIPT in the future. In the meantime, having a "plan B" prepared for those patients for whom NIPT is unsuccessful is essential in today's clinical practice.
Collapse
Affiliation(s)
- Lisa Hui
- Reproductive Epidemiology Group, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Obstetrics and Gynaecology, University of Melbourne, Parkville, Victoria, Australia.,Department of Perinatal Medicine, Mercy Hospital for Women, Heidelberg, Victoria, Australia.,Department of Obstetrics and Gynaecology, Northern Health, Epping, Victoria, Australia
| | - Diana W Bianchi
- Prenatal Genomics and Therapy Section, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.,Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| |
Collapse
|
31
|
Hedriana H, Martin K, Saltzman D, Billings P, Demko Z, Benn P. Cell-free DNA fetal fraction in twin gestations in single-nucleotide polymorphism-based noninvasive prenatal screening. Prenat Diagn 2019; 40:179-184. [PMID: 31711265 PMCID: PMC7027570 DOI: 10.1002/pd.5609] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/19/2019] [Accepted: 10/26/2019] [Indexed: 12/14/2022]
Abstract
Objectives The performance of noninvasive prenatal screening (NIPS) for fetal aneuploidy in twin pregnancies is dependent on the amount of placentally derived cell‐free DNA, the “fetal fraction (FF),” present in maternal plasma. We report FF values in monozygotic (MZ) and dizygotic (DZ) pregnancies. Methods We reviewed FF in pregnancies at 10 to 20 completed weeks gestational age based on single‐nucleotide polymorphism (SNP)‐based NIPS where zygosity was routinely established in twin pregnancies. The cohort included 121 446 (96.3%) singleton, 1454 (1.2%) MZ, and 3161 (2.5%) DZ pregnancies. For DZ twins, individual FFs were measured. Results Combined FF for DZ and MZ fetuses were 35% and 26% greater than singletons, respectively. The individual FF contributions from each fetus in DZ twins were, on average, 32% less than singletons. FF in DZ twin pairs were moderately correlated (Pearson correlation coefficient.66). When a threshold of 2.8% FF was applied to define uninterpretable results, 1.7% (2102/121 446) of singletons, 0.8% (11/1454) of MZ pairs, and 5.6% (178/3161) of DZ pairs were uninterpretable. Conclusion For optimal aneuploidy NIPS in twin pregnancies, zygosity should be established and in DZ twins FF for both fetuses should be determined to identify those cases where results can be reliably interpreted. What's already known about this topic?
Adequate cell‐free fetal DNA (fetal fraction [FF]) is essential for noninvasive prenatal screening. FFs in twin pregnancies may be higher or lower than that found in singleton pregnancies.
What does this study add?
In this large series of twin pregnancies, the average total FF was higher than for singletons but the per fetus FF was lower. There can be large differences in the two FFs in dizygotic twin pregnancies. Optimal prenatal aneuploidy screening in twin pregnancies requires information on both zygosity and the individual FFs.
Collapse
Affiliation(s)
- Herman Hedriana
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of California Davis Health, Sacramento, CA
| | | | | | | | | | - Peter Benn
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT
| |
Collapse
|
32
|
Norwitz ER, McNeill G, Kalyan A, Rivers E, Ahmed E, Meng L, Vu P, Egbert M, Shapira M, Kobara K, Parmar S, Goel S, Prins SA, Aruh I, Persico N, Robins JC, Kirshon B, Demko ZP, Ryan A, Billings PR, Rabinowitz M, Benn P, Martin KA, Hedriana HL. Validation of a Single-Nucleotide Polymorphism-Based Non-Invasive Prenatal Test in Twin Gestations: Determination of Zygosity, Individual Fetal Sex, and Fetal Aneuploidy. J Clin Med 2019; 8:E937. [PMID: 31261782 PMCID: PMC6679081 DOI: 10.3390/jcm8070937] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/20/2019] [Accepted: 06/26/2019] [Indexed: 12/19/2022] Open
Abstract
We analyzed maternal plasma cell-free DNA samples from twin pregnancies in a prospective blinded study to validate a single-nucleotide polymorphism (SNP)-based non-invasive prenatal test (NIPT) for zygosity, fetal sex, and aneuploidy. Zygosity was evaluated by looking for either one or two fetal genome complements, fetal sex was evaluated by evaluating Y-chromosome loci, and aneuploidy was assessed through SNP ratios. Zygosity was correctly predicted in 100% of cases (93/93; 95% confidence interval (CI) 96.1%-100%). Individual fetal sex for both twins was also called with 100% accuracy (102/102; 95% weighted CI 95.2%-100%). All cases with copy number truth were also correctly identified. The dizygotic aneuploidy sensitivity was 100% (10/10; 95% CI 69.2%-100%), and overall specificity was 100% (96/96; 95% weighted CI, 94.8%-100%). The mean fetal fraction (FF) of monozygotic twins (n = 43) was 13.0% (standard deviation (SD), 4.5%); for dizygotic twins (n = 79), the mean lower FF was 6.5% (SD, 3.1%) and the mean higher FF was 8.1% (SD, 3.5%). We conclude SNP-based NIPT for zygosity is of value when chorionicity is uncertain or anomalies are identified. Zygosity, fetal sex, and aneuploidy are complementary evaluations that can be carried out on the same specimen as early as 9 weeks' gestation.
Collapse
Affiliation(s)
- Errol R Norwitz
- Tufts Medical Center and Tufts University School of Medicine, Boston, MA 02111, USA
| | | | | | | | | | - Ling Meng
- Natera, Inc., San Carlos, CA 94070, USA
| | | | | | | | | | | | | | | | - Israel Aruh
- Dr. Israel Aruh's IVF and Infertility Clinic, 35220 Izmir, Turkey
| | | | - Jared C Robins
- Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Brian Kirshon
- Houston Perinatal Associates, Houston, TX 77054, USA
| | | | | | | | | | | | | | - Herman L Hedriana
- Natera, Inc., San Carlos, CA 94070, USA.
- University of California Davis Health, Sacramento, CA 95819, USA.
| |
Collapse
|
33
|
Non-invasive prenatal screening: A 20-year experience in Italy. Eur J Obstet Gynecol Reprod Biol X 2019; 3:100050. [PMID: 31403132 PMCID: PMC6687402 DOI: 10.1016/j.eurox.2019.100050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/02/2019] [Accepted: 05/14/2019] [Indexed: 01/09/2023] Open
Abstract
Over the past two decades, there has been a rapid evolution in prenatal screening for fetal chromosome abnormalities. Initially, testing was focused on the identification of affected pregnancies in either the first, or, the second trimester (e.g. the Combined test or the triple test). This was replaced by sequential modalities (e.g. contingent screening) that have enhanced detection while reducing the need for invasive testing. More recently, the introduction of technologies based on cell-free DNA (cfDNA) in maternal plasma and enrichment of fetal cells in maternal circulation have further refined the concept of sequential screening. In this review, we document our experience with serum and ultrasound-based contingent screening where we were able to achieve a detection rate of 96.8%, a false-positive rate of 2.8% and an odds of being affected given a positive result of 1:11. We also describe our initial experience with a novel sequential protocol that includes the analysis of fetal cells in maternal blood. Methods for enrichment for fetal cells cfDNA and cfDNA technologies offer the possibility of greater sensitivity and specificity as well as expansion in the scope of genetic disorders detectable. As costs decline, these technologies will become increasingly used as primary screening tools. In the meantime, sequential use offers a practical approach to maximizing the benefits of prenatal testing.
Collapse
|
34
|
Abstract
Plasma cryopreservation is unavoidable in China, due to technical specifications requiring storage of additional plasma at −80 degrees for three years. However, the effect of freezing on non-invasive prenatal testing (NIPT) is still uncertain. We collected 144 euploid pregnant samples, 22 on trisomy 21, 4 on trisomy 13, and 3 on trisomy 18, by massively parallel sequencing before and after freezing. Compared with the success rate of 100% of fresh samples, the detection success rates of trisomy 21, trisomy 13 and euploidy in frozen samples by NIPT were 95.45%, 75% and 95.14%, respectively. Of these, 9 cases of frozen sample sequencing failed, with 8 cases being due to high GC content. The chromosome 21 (chr21) z-value of the frozen trisomy 21 samples was lower than that of fresh samples. Meanwhile, freezing reduced the male positive foetal cell-free DNA (cfDNA) fraction, which was accompanied by an increase in the Unimap-GC level in the massively parallel sequencing data and a decrease in the Unique reads/Total reads ratio. Laboratory freezing reduced the chr21 z-value of foetal trisomy 21, which can be explained by a reduction in the foetal cfDNA fraction and effective Unique reads for NIPT analysis. The Unimap-GC content of the serum samples after freezing was higher, which can lead to failure of NIPT detection.
Collapse
|