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Kwan AHW, Gil MM, Xue S, Kwok YKY, Lau D, Fung J, Chan A, Choy KW, Leung TY, Poon LC. Cell-free DNA test for fetal chromosomal abnormalities in multiple pregnancies. Acta Obstet Gynecol Scand 2024; 103:1799-1807. [PMID: 38924543 PMCID: PMC11324921 DOI: 10.1111/aogs.14901] [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: 09/05/2023] [Revised: 05/07/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024]
Abstract
INTRODUCTION This study aimed to report the screening performance of cell-free DNA (cfDNA) testing for chromosomal abnormalities in twins, triplets, and vanishing twin pregnancies. MATERIAL AND METHODS Data were obtained from pregnant women with a multiple pregnancy or a vanishing twin pregnancy at ≥10 weeks' gestation who requested self-financed cfDNA testing between May 2015 and December 2021. Those that had positive screening results had diagnostic confirmatory procedures after counseling and consent. The performance of screening of the cfDNA test was determined by calculating confirmation rate and combined false-positive rate (cFPR). RESULTS Data from 292 women were included after exclusion of those lost to follow-up, with no-result on cfDNA testing, or had reductions. Of the 292 pregnancies, 10 (3.4%) were triplets, including no cases of trisomy 21 and trisomy 18; 249 (85.3%) were twins, including 3 cases of trisomy 21 and no cases of trisomy 18 and 13; and 33 (11.3%) were vanishing twins, including 3 cases of trisomy 21 and 1 case of trisomy 18. The median (IQR) maternal age was 34 years (31-37). For triplet pregnancies, the initial no-result rate was 10.3% (95% confidence interval [CI] 3.6-26.4), all with results after redraw. For twin pregnancies, the initial no-result rate was 12.9% (95% CI 9.6-17.0), and the no-result rate after redraw was 1.6% (95% CI 0.7-3.6). For vanishing twins, there were no cases with no-result. All triplets had low-risk cfDNA results. The confirmation rate for trisomy 21 was 100% with a FPR at 0% due to the small number of positive cases for twins. For vanishing twins, one high-risk case for trisomy 21 and the only high-risk case for trisomy 18 were confirmed with a cFPR of 8.3% (n = 2/24; 95% CI 2.3-25.9). CONCLUSIONS cfDNA testing in twin pregnancies has sufficient screening performance for trisomy 21 but the number of affected cases for other conditions is limited to draw any meaningful conclusion. The use of cfDNA testing in triplet pregnancies and vanishing twins remains an area for further research.
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Affiliation(s)
- Angel H W Kwan
- Department of Obstetrics and Gynecology, The Chinese University of Hong Kong, Hong Kong SAR
| | - Maria Mar Gil
- Obstetrics and Gynecology Department, Hospital Universitario de Torrejón, Madrid, Spain
- Francisco de Vitoria University, Madrid, Spain
| | - Shuwen Xue
- Department of Obstetrics and Gynecology, The Chinese University of Hong Kong, Hong Kong SAR
| | - Yvonne K Y Kwok
- Department of Obstetrics and Gynecology, The Chinese University of Hong Kong, Hong Kong SAR
| | | | - Joanna Fung
- Department of Obstetrics and Gynecology, The Chinese University of Hong Kong, Hong Kong SAR
| | - Andrea Chan
- Department of Obstetrics and Gynecology, United Christian Hospital, New Kowloon, Hong Kong SAR
| | - Kwong Wai Choy
- Department of Obstetrics and Gynecology, The Chinese University of Hong Kong, Hong Kong SAR
| | - Tak Yeung Leung
- Department of Obstetrics and Gynecology, The Chinese University of Hong Kong, Hong Kong SAR
| | - Liona C Poon
- Department of Obstetrics and Gynecology, The Chinese University of Hong Kong, Hong Kong SAR
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Raymond Y, Fernando S, Menezes M, Mol BW, McLennan A, da Silva Costa F, Hardy T, Rolnik DL. Placental, maternal, fetal, and technical origins of false-positive cell-free DNA screening results. Am J Obstet Gynecol 2024; 230:381-389. [PMID: 38008147 DOI: 10.1016/j.ajog.2023.11.1240] [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: 09/05/2023] [Revised: 11/05/2023] [Accepted: 11/16/2023] [Indexed: 11/28/2023]
Abstract
The introduction of noninvasive prenatal testing has resulted in substantial reductions to previously accepted false-positive rates of prenatal screening. Despite this, the possibility of false-positive results remains a challenging consideration in clinical practice, particularly considering the increasing uptake of genome-wide noninvasive prenatal testing, and the subsequent increased proportion of high-risk results attributable to various biological events besides fetal aneuploidy. Confined placental mosaicism, whereby chromosome anomalies exclusively affect the placenta, is perhaps the most widely accepted cause of false-positive noninvasive prenatal testing. There remains, however, a substantial degree of ambiguity in the literature pertaining to the clinical ramifications of confined placental mosaicism and its potential association with placental insufficiency, and consequentially adverse pregnancy outcomes including fetal growth restriction. Other causes of false-positive noninvasive prenatal testing include vanishing twin syndrome, in which the cell-free DNA from a demised aneuploidy-affected twin triggers a high-risk result, technical failures, and maternal origins of abnormal cell-free DNA such as uterine fibroids or unrecognized mosaicisms. Most concerningly, maternal malignancies are also a documented cause of false-positive screening results. In this review, we compile what is currently known about the various causes of false-positive noninvasive prenatal testing.
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Affiliation(s)
- Yvette Raymond
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia.
| | - Shavi Fernando
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia; Monash Women's, Monash Health, Melbourne, Australia; Monash Obstetrics, Melbourne, Australia
| | - Melody Menezes
- Monash Ultrasound for Women, Melbourne, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Australia; Monash IVF Group, Melbourne, Australia
| | - Ben W Mol
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia; Monash Women's, Monash Health, Melbourne, Australia; Centre for Women's Health Research, The University of Aberdeen, Aberdeen, UK
| | - Andrew McLennan
- Sydney Ultrasound for Women, Sydney, Australia; Discipline of Obstetrics, Gynaecology and Neonatology, The University of Sydney, Sydney, Australia
| | - Fabricio da Silva Costa
- Maternal Fetal Medicine Unit, Gold Coast University Hospital, Queensland, Australia; School of Medicine and Dentistry, Griffith University, Gold Coast, Queensland, Australia
| | - Tristan Hardy
- Monash IVF Group, Melbourne, Australia; Repromed Adelaide, Dulwich, Australia
| | - Daniel L Rolnik
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia; Monash Women's, Monash Health, Melbourne, Australia; Monash Ultrasound for Women, Melbourne, Australia
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3
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Boo HY, Han YJ. Cell-free DNA screening in twin pregnancies. Obstet Gynecol Sci 2024; 67:160-168. [PMID: 38268143 PMCID: PMC10948209 DOI: 10.5468/ogs.23135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 08/18/2023] [Accepted: 01/16/2024] [Indexed: 01/26/2024] Open
Abstract
Cell-free DNA (cfDNA) screening for fetal aneuploidies is clinically available and exhibits better performance than conventional serum screening tests. However, data on the clinical performance of cfDNA screening in twin pregnancies are limited. In this review, we summarized the clinical performance and evaluated the feasibility of cfDNA screening in twin pregnancies based on recent studies and recommendations. The performance of cfDNA screening for trisomy 21 in twin pregnancies is similar to that in singleton pregnancies. Specifically, cfDNA screening has a higher detection rate and lower false-positive rate compared with conventional serum screening. Consequently, recent international guidelines from several academic communities have recommended that cfDNA screening for aneuploidy in twin pregnancies could be considered. Moreover, twin pregnancies can present with specific conditions, such as different zygosities and vanishing twins; therefore, individualized counseling and management are required. Further clinical studies with more twin pregnancies are required for a more accurate analysis.
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Affiliation(s)
- Hye Yeon Boo
- Department of Obstetrics and Gynecology, CHA Ilsan Medical Center, Goyang,
Korea
| | - You Jung Han
- Department of Obstetrics and Gynecology, CHA Gangnam Medical Center, Seoul,
Korea
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Hopkins MK, Neumann O, Kuller JA, Dugoff L. First Trimester Ultrasound and Aneuploidy Screening in Twins. Clin Obstet Gynecol 2023; 66:774-780. [PMID: 37438894 DOI: 10.1097/grf.0000000000000797] [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: 07/14/2023]
Abstract
All patients with twin pregnancy should have first trimester ultrasound and be offered screening for chromosomal aneuploidy as well as diagnostic testing. Screening for aneuploidy in twins presents unique challenges compared with singletons. Cell-free DNA screening should be considered first-line; however, this option may not be available or may have limitations in certain clinical scenarios, such as vanishing twins. If cell-free DNA screening is not available, maternal serum marker screening in conjunction with nuchal translucency assessment should be offered. Patients with positive aneuploidy screening tests or fetal structural abnormalities should be offered diagnostic testing.
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Affiliation(s)
- Maeve K Hopkins
- Obstetrics & Gynecology Institute, Cleveland Clinic, Cleveland, Ohio
| | - Olivia Neumann
- Obstetrics & Gynecology Institute, Cleveland Clinic, Cleveland, Ohio
| | - Jeffrey A Kuller
- Division of Maternal and Fetal Medicine, Duke University Hospital, Durham, North Carolina
| | - Lorraine Dugoff
- Divisions of Maternal and Fetal Medicine and Reproductive Genetics, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
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5
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Sondgeroth KE. Twin Gestation With Spontaneous Reduction To Singleton. Clin Obstet Gynecol 2023; 66:792-803. [PMID: 37910065 DOI: 10.1097/grf.0000000000000820] [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: 11/03/2023]
Abstract
Twin gestations are at increased risk of single intrauterine fetal death. A first-trimester loss is a common complication in twin gestations. The rate of co-twin morbidity and mortality is higher when a single demise occurs in the second and third trimesters. Monochorionicity strongly influences the prognosis for the surviving co-twin. Fetal ultrasound combined with MRI may be able to help predict neurological injury to the surviving co-twin. The rate of co-twin demise decreases with advancing gestation. After single intrauterine fetal demise, monochorionic gestations should be delivered by 34 weeks and dichorionic by 36 to 37 weeks gestation.
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Lee DR, Lee S, Lee SJ. The effect of a vanishing twin on first- and second-trimester maternal serum markers and ultrasound screening for aneuploidy. Obstet Gynecol Sci 2023; 66:477-483. [PMID: 37532226 PMCID: PMC10663394 DOI: 10.5468/ogs.22270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 05/24/2023] [Accepted: 07/06/2023] [Indexed: 08/04/2023] Open
Abstract
A vanishing twin (VT) is the early demise of a twin fetus. It is estimated to occur in 20-30% of pregnancies associated with assisted reproductive technology. VT becomes increasingly prominent when assisted fertilization is used, because one or more embryos are transferred to the uterus. Maternal serum screening tests during pregnancy can screen for trisomy chromosomes 21, 18, and 13 and are divided into first- and second-trimester tests. In singleton pregnancies, the first trimester screening test is performed at 11-13 weeks and 6 days of gestation. It consists of two serum markers, pregnancy-associated plasma protein A and β-human chorionic gonadotropin (β-hCG), and measures nuchal translucency thickness. The second-trimester screening test was performed at 15-20 weeks and 6 days of gestation. It consists of four serum markers: alpha-fetoprotein, β-hCG, unconjugated estriol, and inhibin A. More effective screening for trisomy 21 in singleton pregnancies is achieved by analyzing cell-free DNA in the maternal blood. A VT includes a demise of the fetus. Although it affects maternal serum markers, it has not been corrected. Five studies examined the effect of VT on maternal serum markers, but the results were controversial. This study aimed to review the patterns of changes in maternal serum markers in VTs, interpret prenatal tests for pregnant women with VTs in clinical practice, and consider what information should be provided.
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Affiliation(s)
- Da Rae Lee
- Department of Obstetrics and Gynecology, Kangwon National University Hospital, School of Medicine, Kangwon National University, Chuncheon,
Korea
| | - SeungMi Lee
- Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul,
Korea
| | - Se Jin Lee
- Department of Obstetrics and Gynecology, Kangwon National University Hospital, School of Medicine, Kangwon National University, Chuncheon,
Korea
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7
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Chen CP. False positive non-invasive prenatal testing (NIPT) for trisomy 21 in vanishing twin syndrome pregnancy: A comparison of the NIPT results performed in different gestations. Taiwan J Obstet Gynecol 2023; 62:929-930. [PMID: 38008520 DOI: 10.1016/j.tjog.2023.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2023] [Indexed: 11/28/2023] Open
Affiliation(s)
- Chih-Ping Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; Institute of Clinical and Community Health Nursing, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Obstetrics and Gynecology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Medical Laboratory Science and Biotechnology, College of Medical and Health Science, Asia University, Taichung, Taiwan.
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8
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Buckley L, Hopkins M, Kuller JA, Dugoff L. Prenatal Genetic Screening in Twin Pregnancy. Clin Obstet Gynecol 2023; 66:624-628. [PMID: 37436940 DOI: 10.1097/grf.0000000000000805] [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: 07/14/2023]
Abstract
Twin pregnancy presents unique considerations for aneuploidy screening. Pre-test counseling regarding benefits, alternatives, and options for aneuploidy screening should be provided to all patients carrying twin pregnancy. This article aims to review the options for aneuploidy screening in twin pregnancy including the potential benefits and limitations.
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Affiliation(s)
- Lauren Buckley
- Obstetrics & Gynecology Institute, Cleveland Clinic, Cleveland, Ohio
| | - Maeve Hopkins
- Obstetrics & Gynecology Institute, Cleveland Clinic, Cleveland, Ohio
| | - Jeffrey A Kuller
- Division of Maternal and Fetal Medicine, Duke University Hospital, Durham, North Carolina
| | - Lorraine Dugoff
- Division of Maternal and Fetal Medicine and Reproductive Genetics, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
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9
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Dungan JS, Klugman S. Response to Prensky and Persson. Genet Med 2023; 25:100873. [PMID: 37266582 DOI: 10.1016/j.gim.2023.100873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 06/03/2023] Open
Affiliation(s)
- Jeffrey S Dungan
- Division of Clinical Genetics, Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Susan Klugman
- Division of Reproductive and Medical Genetics, Department of Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine/Montefiore Medical Center, New York, NY
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10
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Balaguer N, Mateu-Brull E, Gómez-López M, Simón C, Milán M. Cell-free fetal DNA testing performance and fetal fraction estimation are not affected in ART-conceived pregnancies. Hum Reprod 2022; 37:2743-2756. [PMID: 36223600 DOI: 10.1093/humrep/deac217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 09/06/2022] [Indexed: 12/14/2022] Open
Abstract
STUDY QUESTION Does ART-based conception influence fetal fraction (FF) estimation and cell-free fetal DNA (cffDNA) testing performance? SUMMARY ANSWER Mode of conception (ART versus natural) does not impact FF estimation or cffDNA test informativity rates. WHAT IS KNOWN ALREADY Pregnancies achieved via ART are increasing, and cffDNA testing is displacing traditional prenatal screening methods due to its high sensitivity and specificity and noninvasive nature. However, conflicting data exist on cffDNA testing performance and FF in ART pregnancies compared with natural pregnancies. STUDY DESIGN, SIZE, DURATION We performed a case-control study that included 21 558 consecutive pregnancies (spontaneous, n = 15 707; ART, n = 5851). ART-conceived pregnancies were stratified into two groups according to oocyte origin. Samples were collected from April 2015 to September 2019. PARTICIPANTS/MATERIALS, SETTING, METHODS The study included women from different centers worldwide. Blood samples were drawn from the 10th week of gestation onward. Massive parallel whole-genome sequencing was used to analyze cffDNA content in blood plasma. Two different types of technologies (single-end and paired-end) were applied because of analysis technology changes made by the sequencing provider over time. FF was determined using different methods depending on the type of technology used. Cases with an FF <2% or with failure in any quality control metrics were classified as noninformative. An analysis of covariance model was selected to identify which qualitative (sequencing methodology, mode of conception, type (i.e. multiplicity) of gestation and age (women >35 or <35 years old)) and quantitative (gestational age, BMI) variables were predictors of FF value. Multinomial logistic regression was used to evaluate whether the mode of conception impacted cffDNA testing performance. MAIN RESULTS AND THE ROLE OF CHANCE A univariate t-test demonstrated no significant differences in FF values between ART (median FF = 9.2%) and spontaneous pregnancies (median FF = 9.2%). Also, a multivariate analysis showed that the mode of conception, did not strongly impact the percentage of FF. ART-treated women showed a lower incidence of high-risk cffDNA results compared to women who conceived naturally, specifically for trisomy (T)21 (0.7% versus 1.3%, P = 0.001) and T18 (0.1% versus 0.3%, P = 0.001). A multivariate model stratified by type of aneuploidy suggested that these differences were conditioned by oocyte origin, especially for the T21 risk classification (P < 0.0001). False-positive rates (FPRs) were significantly higher in the ART population, mainly for T13 (P = 0.001) and sexual chromosome aneuploidies (SCAs; P < 0.001). A multivariate model suggested that the differences observed in SCAs were caused by sequencing modality rather than by mode of conception. Likewise, ART-treated women who used their own oocytes had a higher probability of a false positive for T13 (P = 0.004). LIMITATIONS, REASONS FOR CAUTION Our study lacks follow-up data for low- and high-risk cases of both ART-conceived and naturally conceived pregnancies. Therefore, the results comparing FPR in both populations should be interpreted carefully. Also, collecting information about different ART modalities and regarding preimplantation genetic testing for aneuploidy treatments would help draw definite explanations for the trends observed in this study. WIDER IMPLICATIONS OF THE FINDINGS This is the first study that demonstrates, with a large sample size, that FF is not influenced by mode of conception, demystifying the notion that patients undergoing ART have a higher probability of noninformative cffDNA testing results. Multivariate models stratified by oocyte origin and type of aneuploidy demonstrated that ART-conceived pregnancies do not have a higher probability of classification as a high-risk pregnancy in prenatal testing. This information is especially valuable to clinicians and genetic counselors when informing patients about the risks and limitations of cffDNA testing in ART pregnancies. STUDY FUNDING/COMPETING INTEREST(S) This study was financially supported by Igenomix Lab S.L.U. All authors declare no conflict of interest. TRIAL REGISTRATION NUMBER N/A.
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Affiliation(s)
- Nuria Balaguer
- Prenatal Diagnosis Department, Igenomix Spain Lab S.L.U., Paterna (Valencia), Spain
| | - Emilia Mateu-Brull
- Prenatal Diagnosis Department, Igenomix Spain Lab S.L.U., Paterna (Valencia), Spain
| | - María Gómez-López
- Prenatal Diagnosis Department, Igenomix Spain Lab S.L.U., Paterna (Valencia), Spain
| | - Carlos Simón
- Igenomix S.L., Obstetrics & Gynecology, Valencia University, Valencia, Spain.,Beth Israel Deaconess Medical Center, Harvard University, Boston, MA, USA.,Department of Obstetrics & Gynecology, Baylor College of Medicine, Houston, TX, USA
| | - Miguel Milán
- Prenatal Diagnosis Department, Igenomix Spain Lab S.L.U., Paterna (Valencia), Spain
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Noninvasive Prenatal Screening for Trisomy 21 in Patients with a Vanishing Twin. Genes (Basel) 2022; 13:genes13112027. [DOI: 10.3390/genes13112027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 10/23/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
A vanishing twin (VT) occurs in up to 30% of early diagnosed twin pregnancies and is associated with an increased risk of fetal aneuploidy. Here, we describe our experience in a large VT population of 847 patients that underwent noninvasive prenatal testing (NIPT) for common fetal trisomies over a three-year period. All patients underwent an ultrasound examination prior to NIPT. Two comparison populations were included, namely, the singleton (n = 105,560) and the viable multiple gestation pregnancy samples (n = 9691) collected over the same period. All NIPT samples in the VT population received a result, of which 14 were high-risk for trisomy 21 (1.6%), nine for trisomy 18 (1.1%), and six for trisomy 13 (0.7%). Diagnostic testing confirmed the presence of trisomy 21 in 6/12 samples, giving a positive predictive value of 50%. One trisomy 18 case and no trisomy 13 cases were confirmed. The time between fetal demise and NIPT sampling did not appear to affect the number of true- or false-positive cases. In conclusion, NIPT is an effective screening method for trisomy 21 in the surviving fetus(es) in VT pregnancies. For trisomies 18 and 13, a positive NIPT should be interpreted carefully and ultrasound monitoring is preferrable over invasive diagnostic testing.
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D'Antonio F, Khalil A. Screening and diagnosis of chromosomal abnormalities in twin pregnancy. Best Pract Res Clin Obstet Gynaecol 2022; 84:229-239. [DOI: 10.1016/j.bpobgyn.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 10/02/2022] [Indexed: 11/16/2022]
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13
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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
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Affiliation(s)
| | | | | | | | | | | | - Peter Benn
- Department of Genetics and Genome Sciences UConn Health Farmington San Carlos CT USA
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14
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Mysteries of Monozygosity: Theories and Breakthroughs/Twin Research: Rare Case of Lost Twins; Developing a National Twin Registry; Twins' Language and Gesture Delays; DNA Testing for Vanishing Twins/Media Reports: Identical Twins Discordant for COVID Vaccination; World's Oldest Identical Twins; Olympic Athlete Stand-in; Fraternal Twin Football Players. Twin Res Hum Genet 2022; 24:408-412. [PMID: 35074029 DOI: 10.1017/thg.2021.51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The processes that give rise to monozygotic (MZ) twins remain elusive. This article describes various theories of MZ twinning that have been examined over the years, although they continue to be speculative. It has also been impossible to know if a singleton began life as an MZ twin; however, a critical technological breakthrough can now reveal this important birth history information with a high degree of certainty. The section that follows presents reviews of current research regarding rare twin loss, development of a twin registry, twins' communicative delays and DNA testing for vanishing twins. The article concludes with a survey of newsworthy twins, namely identical twins discordant for COVID vaccination, the world's oldest identical twins, an Olympic athletic stand-in and fraternal twin football players.
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15
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Deng C, Liu S. Factors Affecting the Fetal Fraction in Noninvasive Prenatal Screening: A Review. Front Pediatr 2022; 10:812781. [PMID: 35155308 PMCID: PMC8829468 DOI: 10.3389/fped.2022.812781] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/03/2022] [Indexed: 12/03/2022] Open
Abstract
A paradigm shift in noninvasive prenatal screening has been made with the discovery of cell-free fetal DNA in maternal plasma. Noninvasive prenatal screening is primarily used to screen for fetal aneuploidies, and has been used globally. Fetal fraction, an important parameter in the analysis of noninvasive prenatal screening results, is the proportion of fetal cell-free DNA present in the total maternal plasma cell-free DNA. It combines biological factors and bioinformatics algorithms to interpret noninvasive prenatal screening results and is an integral part of quality control. Maternal and fetal factors may influence fetal fraction. To date, there is no broad consensus on the factors that affect fetal fraction. There are many different approaches to evaluate this parameter, each with its advantages and disadvantages. Different fetal fraction calculation methods may be used in different testing platforms or laboratories. This review includes numerous publications that focused on the understanding of the significance, influencing factors, and interpretation of fetal fraction to provide a deeper understanding of this parameter.
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Affiliation(s)
- Cechuan Deng
- Prenatal Diagnostic Center, Department of Medical Genetics, 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
| | - Shanling Liu
- Prenatal Diagnostic Center, Department of Medical Genetics, 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
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Hopkins MK, Dugoff L. Screening for aneuploidy in twins. Am J Obstet Gynecol MFM 2021; 4:100499. [PMID: 34634497 DOI: 10.1016/j.ajogmf.2021.100499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/26/2021] [Accepted: 10/03/2021] [Indexed: 10/20/2022]
Abstract
All pregnant women should be offered screening for aneuploidy. Twin pregnancies present unique challenges in aneuploidy screening. This review describes available aneuploidy screening options and their benefits and limitations in twin pregnancy, along with describing special circumstances, such as vanishing twins and diagnostic testing in twin pregnancy. No method of aneuploidy screening is as accurate in twin pregnancies as singleton pregnancies. Cell-free DNA screening should be considered a first-line approach; however, this option may not be available or may have limitations in certain clinical scenarios, such as vanishing twins. If cell-free DNA screening is not available, nuchal translucency and/or maternal serum marker screening can be offered.
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Affiliation(s)
- Maeve K Hopkins
- Division of Maternal and Fetal Medicine, Ob/Gyn & Women's Health Institute, Cleveland Clinic, Cleveland, OH (Dr Hopkins).
| | - Lorraine Dugoff
- Divisions of Maternal and Fetal Medicine and Reproductive Genetics, Department of Obstetrics and Gynecology, Hospital of the University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA (Dr Dugoff)
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Chitty LS. Non-invasive prenatal testing 10 years on. Prenat Diagn 2021; 41:1187-1189. [PMID: 34418119 DOI: 10.1002/pd.6032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 01/26/2023]
Affiliation(s)
- Lyn S Chitty
- Great Ormond Street NHS Foundation Trust and the UCL GOS Institute of Child Health, London, UK
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Performance and Diagnostic Value of Genome-Wide Noninvasive Prenatal Testing in Multiple Gestations. Obstet Gynecol 2021; 137:1102-1108. [PMID: 33957658 DOI: 10.1097/aog.0000000000004385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/28/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate the accuracy and diagnostic value of genome-wide noninvasive prenatal testing (NIPT) for the detection of fetal aneuploidies in multiple gestations, with a focus on dichorionic-diamniotic twin pregnancies. METHODS We performed a retrospective cohort study including data from pregnant women with a twin or higher-order gestation who underwent genome-wide NIPT at one of the eight Belgian genetic centers between November 1, 2013, and March 1, 2020. Chorionicity and amnionicity were determined by ultrasonography. Follow-up invasive testing was carried out in the event of positive NIPT results. Sensitivity and specificity were calculated for the detection of trisomy 21, 18, and 13 in the dichorionic-diamniotic twin cohort. RESULTS Unique NIPT analyses were performed for 4,150 pregnant women with a multiple gestation and an additional 767 with vanishing gestations. The failure rate in multiple gestations excluding vanishing gestations ranged from 0% to 11.7% among the different genetic centers. Overall, the failure rate was 4.8%, which could be reduced to 1.2% after single resampling. There were no common fetal trisomies detected among the 86 monochorionic-monoamniotic and 25 triplet cases. Two monochorionic-diamniotic twins had an NIPT result indicative of a trisomy 21, which was confirmed in both fetuses. Among 2,716 dichorionic-diamniotic twin gestations, a sensitivity of 100% (95% CI 74.12-100%) and a specificity of 100% (95% CI 99.86-100%) was reached for trisomy 21 (n=12). For trisomy 18 (n=3), the respective values were 75% (95% CI 30.06-95.44%) sensitivity and 100% (95% CI 99.86-100%) specificity, and for trisomy 13 (n=2), 100% (95% CI 20.65-100%) sensitivity and 99.96% (95% CI 99.79-99.99%) specificity. In the vanishing gestation group, 28 NIPT results were positive for trisomy 21, 18, or 13, with only five confirmed trisomies. CONCLUSION Genome-wide NIPT performed accurately for detection of aneuploidy in dichorionic-diamniotic twin gestations.
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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.
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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
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