1
|
Kovaleva NV, Cotter PD. Mosaicism for Autosomal Trisomies: A Comprehensive Analysis of 1266 Published Cases Focusing on Maternal Age and Reproductive History. Genes (Basel) 2024; 15:778. [PMID: 38927714 PMCID: PMC11202781 DOI: 10.3390/genes15060778] [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: 04/21/2024] [Revised: 06/06/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
Mosaicism for autosomal trisomy is uncommon in clinical practice. However, despite its rarity among both prenatally and postnatally diagnoses, there are a large number of characterized and published cases. Surprisingly, in contrast to regular trisomies, no attempts at systematic analyses of mosaic carriers' demographics were undertaken. This is the first study aimed to address this gap. For that, we have screened more than eight hundred publications on mosaic trisomies, reviewing data including gender and clinical status of mosaic carriers, maternal age and reproductive history. In total, 596 publications were eligible for analysis, containing data on 948 prenatal diagnoses, including true fetal mosaicism (TFM) and confined placental mosaicism (CPM), and on 318 cases of postnatally detected mosaicism (PNM). No difference was found in maternal age between normal pregnancy outcomes with appropriate birth weight and those with intrauterine growth restriction. Unexpectedly, a higher proportion of advanced maternal ages (AMA) was found in normal outcomes compared to abnormal ones (abnormal fetus or newborn) and fetal losses, 73% vs. 56% and 50%, p = 0.0015 and p = 0.0011, correspondingly. Another intriguing finding was a higher AMA proportion in mosaic carriers with concomitant uniparental disomy (UPD) for chromosomes 7, 14, 15, and 16 compared to carriers with biparental disomy (BPD) (72% vs. 58%, 92% vs. 55%, 87% vs. 78%, and 65% vs. 24%, correspondingly); overall figures were 78% vs. 48%, p = 0.0026. Analysis of reproductive histories showed a very poor reporting but almost two-fold higher rate of mothers reporting a previous fetal loss from PNM cohort (in which almost all patients were clinically abnormal) compared to mothers from the TFM and CPM cohorts (with a large proportion of normal outcomes), 30% vs. 16%, p = 0.0072. The occurrence of a previous pregnancy with a chromosome abnormality was 1 in 13 in the prenatal cohort and 1 in 16 in the postnatal cohort, which are five-fold higher compared to published studies on non-mosaic trisomies. We consider the data obtained in this study to be preliminary despite the magnitude of the literature reviewed since reporting of detailed data was mostly poor, and therefore, the studied cohorts do not represent "big data". Nevertheless, the information obtained is useful both for clinical genetic counseling and for modeling further studies.
Collapse
Affiliation(s)
- Natalia V. Kovaleva
- Academy of Molecular Medicine, Mytniskaya Str. 12/44, 191144 St. Petersburg, Russia
| | | |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Qin S, Wang X, Wang J, Xi N, Yan M, He Y, Ye M, Zhang Z, Yin Y. Prenatal diagnosis of mosaic chromosomal aneuploidy and uniparental disomy and clinical outcomes evaluation of four fetuses. Mol Cytogenet 2023; 16:35. [PMID: 38057902 DOI: 10.1186/s13039-023-00667-9] [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: 09/28/2023] [Accepted: 11/21/2023] [Indexed: 12/08/2023] Open
Abstract
BACKGROUND Few co-occurrence cases of mosaic aneuploidy and uniparental disomy (UPD) chromosomes have been reported in prenatal periods. It is a big challenge for us to predict fetal clinical outcomes with these chromosome abnormalities because of their highly heterogeneous clinical manifestations and limited phenotype attainable by ultrasound. METHODS Amniotic fluid samples were collected from four cases. Karyotype, chromosome microarray analysis, short tandem repeats, and whole exome sequencing were adopted to analyze fetal chromosomal aneuploidy, UPD, and gene variation. Meanwhile, CNVseq analysis proceeded for cultured and uncultured amniocytes in case 2 and case 4 and MS-MLPA for chr11 and chr15 in case 3. RESULTS All four fetuses showed mosaic chromosomal aneuploidy and UPD simultaneously. The results were: Case 1: T2(7%) and UPD(2)mat(12%). Case 2: T15(60%) and UPD(15)mat(40%). Case 3: 45,X(13%) and genome-wide paternal UPD(20%). Case 4: <10% of T20 and > 90% UPD(20)mat in uncultured amniocyte. By analyzing their formation mechanism of mosaic chromosomal aneuploidy and UPD, at least two adverse genetic events happened during their meiosis and mitosis. The fetus of case 1 presented a benign with a normal intrauterine phenotype, consistent with a low proportion of trisomy cells. However, the other three fetuses had adverse pregnancy outcomes, resulting from the UPD chromosomes with imprinted regions involved or a higher level of mosaic aneuploidy. CONCLUSION UPD is often present with mosaic aneuploidy. It is necessary to analyze them simultaneously using a whole battery of analyses for these cases when their chromosomes with imprinted regions are involved or known carriers of a recessive allele. Fetal clinical outcomes were related to the affected chromosomes aneuploidy and UPD, mosaic levels and tissues, methylation status, and homozygous variation of recessive genes on the UPD chromosome. Genetic counseling for pregnant women with such fetuses is crucial to make informed choices.
Collapse
Affiliation(s)
- Shengfang Qin
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, 610045, Sichuan, China.
| | - Xueyan Wang
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, 610045, Sichuan, China
| | - Jin Wang
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, 610045, Sichuan, China
| | - Na Xi
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, 610045, Sichuan, China
| | - Mengjia Yan
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, 610045, Sichuan, China
| | - Yuxia He
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, 610045, Sichuan, China
| | - Mengling Ye
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, 610045, Sichuan, China
| | - Zhuo Zhang
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, 610045, Sichuan, China
| | - Yan Yin
- Department of Medical Genetics and Prenatal Diagnosis, Sichuan Provincial Maternity and Child Health Care Hospital, Chengdu, 610045, Sichuan, China
| |
Collapse
|
4
|
Ma N, Zhu Z, Hu J, Pang J, Yang S, Liu J, Chen J, Tang W, Kuang H, Hu R, Li Z, Wang H, Peng Y, Xi H. Case report: Detection of fetal trisomy 9 mosaicism by multiple genetic testing methods: Report of two cases. Front Genet 2023; 14:1121121. [PMID: 36968600 PMCID: PMC10036773 DOI: 10.3389/fgene.2023.1121121] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/27/2023] [Indexed: 03/12/2023] Open
Abstract
Chromosomal mosaicism remains a perpetual diagnostic and clinical dilemma. In the present study, we detected two prenatal trisomy 9 mosaic syndrome cases by using multiple genetic testing methods. The non-invasive prenatal testing (NIPT) results suggested trisomy 9 in two fetuses. Karyotype analysis of amniocytes showed a high level (42%–50%) of mosaicism, and chromosomal microarray analysis (CMA) of uncultured amniocytes showed no copy number variation (CNV) except for large fragment loss of heterozygosity. Ultrasound findings were unmarkable except for small for gestational age. In Case 1, further umbilical blood puncture confirmed 22.4% and 34% trisomy 9 mosaicism by CMA and fluorescent in situ hybridization (FISH) respectively. After comprehensive consideration of the genetic and ultrasound results, the two gravidas decided to receive elective termination and molecular investigations of multiple tissue samples from the aborted fetus and the placenta. The results confirmed the presence of true fetoplacental mosaicism with levels of trisomy 9 mosaicism from 76% to normal in various tissues. These two cases highlight the necessity of genetic counseling for gravidas whose NIPT results highly suggest the risk of chromosome 9 to ascertain the occurrence of mosaicism. In addition, the comprehensive use of multiple genetic techniques and biological samples is recommended for prenatal diagnosis to avoid false-negative results. It should also be noted that ultrasound results of organs with true trisomy 9 mosaicism can be free of structural abnormalities during pregnancy.
Collapse
Affiliation(s)
- Na Ma
- Department of Medical Genetics, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
| | - Zhenhua Zhu
- Department of General Surgery, Changsha Central Hospital Affiliated to University of South China, Changsha, China
| | - Jiancheng Hu
- Department of Medical Genetics, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
| | - Jialun Pang
- Department of Medical Genetics, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
| | - Shuting Yang
- Department of Medical Genetics, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
| | - Jing Liu
- Department of Medical Genetics, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
| | - Jing Chen
- Department of Medical Genetics, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
| | - Wanglan Tang
- Department of Medical Genetics, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
| | - Haiyan Kuang
- Department of Ultrasonography, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
| | - Rong Hu
- Department of Medical Genetics, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
| | - Zhuo Li
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics School of Life Sciences, School of Life Sciences, Central South University, Changsha, China
| | - Hua Wang
- Department of Medical Genetics, Hunan Children’s Hospital, Changsha, China
| | - Ying Peng
- Department of Medical Genetics, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
- *Correspondence: Ying Peng, ; Hui Xi,
| | - Hui Xi
- Department of Medical Genetics, Hunan Provincial Maternal and Child Healthcare Hospital, Changsha, China
- *Correspondence: Ying Peng, ; Hui Xi,
| |
Collapse
|
5
|
Benn P. Rare autosomal trisomies detected by non-invasive prenatal testing. Eur J Hum Genet 2022; 30:1318-1319. [PMID: 36045223 PMCID: PMC9712667 DOI: 10.1038/s41431-022-01174-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 08/06/2022] [Indexed: 11/09/2022] Open
Affiliation(s)
- Peter Benn
- Department of Genetics and Genome Sciences, UConn Health, 263 Farmington Avenue, Farmington, CT, 06032, USA.
| |
Collapse
|
6
|
Wang LQ, Fernandez-Boyano I, Robinson WP. Genetic variation in placental insufficiency: What have we learned over time? Front Cell Dev Biol 2022; 10:1038358. [PMID: 36313546 PMCID: PMC9613937 DOI: 10.3389/fcell.2022.1038358] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/03/2022] [Indexed: 11/28/2022] Open
Abstract
Genetic variation shapes placental development and function, which has long been known to impact fetal growth and pregnancy outcomes such as miscarriage or maternal pre-eclampsia. Early epidemiology studies provided evidence of a strong heritable component to these conditions with both maternal and fetal-placental genetic factors contributing. Subsequently, cytogenetic studies of the placenta and the advent of prenatal diagnosis to detect chromosomal abnormalities provided direct evidence of the importance of spontaneously arising genetic variation in the placenta, such as trisomy and uniparental disomy, drawing inferences that remain relevant to this day. Candidate gene approaches highlighted the role of genetic variation in genes influencing immune interactions at the maternal-fetal interface and angiogenic factors. More recently, the emergence of molecular techniques and in particular high-throughput technologies such as Single-Nucleotide Polymorphism (SNP) arrays, has facilitated the discovery of copy number variation and study of SNP associations with conditions related to placental insufficiency. This review integrates past and more recent knowledge to provide important insights into the role of placental function on fetal and perinatal health, as well as into the mechanisms leading to genetic variation during development.
Collapse
Affiliation(s)
- Li Qing Wang
- BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Icíar Fernandez-Boyano
- BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Wendy P. Robinson
- BC Children’s Hospital Research Institute, Vancouver, BC, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Wendy P. Robinson,
| |
Collapse
|
7
|
Raymond YC, Fernando S, Menezes M, Meagher S, Mol BW, McLennan A, Scott F, Mizia K, Carey K, Fleming G, Rolnik DL. Cell-free DNA screening for rare autosomal trisomies and segmental chromosome imbalances. Prenat Diagn 2022; 42:1349-1357. [PMID: 36068932 PMCID: PMC9826090 DOI: 10.1002/pd.6233] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/02/2022] [Accepted: 08/26/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To assess the outcomes of pregnancies at high-risk for rare autosomal trisomies (RATs) and segmental imbalances (SIs) on cell-free DNA (cfDNA) screening. METHOD A retrospective study of women who underwent cfDNA screening between September 2019 and July 2021 at three ultrasound services in Australia. Positive predictive values (PPVs) were calculated using fetal chromosomal analysis. RESULTS Among 23,857 women screened, there were 93 high-risk results for RATs (0.39%) and 82 for SIs (0.34%). The PPVs were 3.8% (3/78, 95% CI 0.8%-10.8%) for RATs and 19.1% (13/68, 95% CI 10.6%-30.5%) for SIs. If fetuses with structural anomalies were also counted as true-positive cases, the PPV for RATS increased to 8.5% (7/82, 95% CI 3.5%-16.8%). Among 85 discordant cases with birth outcomes available (65.4%), discordant positive RATs had a significantly higher proportion of infants born below the 10th and 3rd birthweight percentiles than expected (19.6% (p = 0.022) and 9.8% (p = 0.004), respectively), which was not observed in the SI group (2.9% < 10th (p = 0.168) and 0.0% <3rd (p = 0.305)). CONCLUSION The PPVs for SI and RAT results are low, except when a structural abnormality is also present. Discordant positive RATs are associated with growth restriction.
Collapse
Affiliation(s)
- Yvette C. Raymond
- Department of Obstetrics and GynecologyMonash UniversityClaytonVictoriaAustralia
| | - Shavi Fernando
- Department of Obstetrics and GynecologyMonash UniversityClaytonVictoriaAustralia,Monash Women'sMonash HealthClaytonVictoriaAustralia
| | - Melody Menezes
- Monash Ultrasound for WomenMelbourneVictoriaAustralia,Department of PediatricsThe University of MelbourneMelbourneVictoriaAustralia
| | - Simon Meagher
- Monash Ultrasound for WomenMelbourneVictoriaAustralia
| | - Ben W. Mol
- Department of Obstetrics and GynecologyMonash UniversityClaytonVictoriaAustralia,Monash Women'sMonash HealthClaytonVictoriaAustralia,Aberdeen Centre for Women's Health ResearchUniversity of AberdeenAberdeenUK
| | - Andrew McLennan
- Sydney Ultrasound for WomenSydneyNew South WalesAustralia,Discipline of Obstetrics, Gynaecology and NeonatologyThe University of SydneySydneyNew South WalesAustralia
| | - Fergus Scott
- Sydney Ultrasound for WomenSydneyNew South WalesAustralia,School of Women's and Children's HealthUniversity of New South WalesSydneyNew South WalesAustralia
| | - Karen Mizia
- Ultrasound CareSydneyNew South WalesAustralia,Australian National UniversityCanberraAustralia
| | - Karen Carey
- Sydney Ultrasound for WomenSydneyNew South WalesAustralia
| | | | - Daniel Lorber Rolnik
- Department of Obstetrics and GynecologyMonash UniversityClaytonVictoriaAustralia,Monash Women'sMonash HealthClaytonVictoriaAustralia
| |
Collapse
|
8
|
Rosner M, Kolbe T, Hengstschläger M. Fetomaternal microchimerism and genetic diagnosis: On the origins of fetal cells and cell-free fetal DNA in the pregnant woman. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2021; 788:108399. [PMID: 34893150 DOI: 10.1016/j.mrrev.2021.108399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 11/11/2021] [Accepted: 11/14/2021] [Indexed: 06/14/2023]
Abstract
During pregnancy several types of fetal cells and fetal stem cells, including pregnancy-associated progenitor cells (PAPCs), traffic into the maternal circulation. Whereas they also migrate to various maternal organs and adopt the phenotype of the target tissues to contribute to regenerative processes, fetal cells also play a role in the pathogenesis of maternal diseases. In addition, cell-free fetal DNA (cffDNA) is detectable in the plasma of pregnant women. Together they constitute the well-known phenomenon of fetomaternal microchimerism, which inspired the concept of non-invasive prenatal testing (NIPT) using maternal blood. An in-depth knowledge concerning the origins of these fetal cells and cffDNA allows a more comprehensive understanding of the biological relevance of fetomaternal microchimerism and has implications for the ongoing expansion of resultant clinical applications.
Collapse
Affiliation(s)
- Margit Rosner
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Thomas Kolbe
- Biomodels Austria, University of Veterinary Medicine Vienna, Vienna, Austria; Department IFA Tulln, University of Natural Resources and Life Sciences, Tulln, Austria
| | - Markus Hengstschläger
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria.
| |
Collapse
|
9
|
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
|
10
|
Grati FR, Malvestiti F, Gallazzi G, Saragozza S, Grimi B, Agrati C, Branca L, Palumbo F, Trotta A, Chinetti S, Simoni G, Ferreira J, Benn P. Performance of conventional cytogenetic analysis on chorionic villi when only one cell layer, cytotrophoblast or mesenchyme alone, is analyzed. Prenat Diagn 2021; 41:652-660. [PMID: 33782989 DOI: 10.1002/pd.5941] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 03/11/2021] [Accepted: 03/22/2021] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To provide an estimation of the probability of error when chorionic villi (CV) cytogenetic analysis is limited to a single placental layer; either a direct preparation (Dir) or long-term culture (LTC). METHODS We retrospectively reviewed cytogenetic studies on 81,593 consecutive CV samples in which both Dir and LTC were analyzed. All mosaic cases received amniocentesis. The false omission and false discovery rates were calculated by assessing the results that would have been reported when analysis was limited to either Dir or LTC. RESULTS For all abnormalities combined, the proportion of normal Dir or LTC only reports that would have been inconsistent with a subsequent amniocentesis was 0.09% and 0.03%, respectively (false omissions). Among abnormal reports based on Dir or LTC alone, 8.01% and 3.17%, respectively, would be inconsistent with a subsequent amniocentesis result (false discoveries). Differences are present for individual abnormalities. CONCLUSIONS From the perspective of identifying all abnormalities of potential clinical significance, the analysis of both placental layers is optimal. LTC alone is the preferred approach if only one layer of placenta is to be analyzed. Although rare, it is important to acknowledge that one cell layer analysis alone can cause misdiagnosis due to undetected mosaicism.
Collapse
Affiliation(s)
- Francesca Romana Grati
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Francesca Malvestiti
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Gloria Gallazzi
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Silvia Saragozza
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Beatrice Grimi
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Cristina Agrati
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Lara Branca
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Federica Palumbo
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Anna Trotta
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Sara Chinetti
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Giuseppe Simoni
- Unit of Research and Development, Cytogenetics and Medical Genetics TOMA, Advanced Biomedical Assays, Impact Lab, Varese, Italy
| | - Jose Ferreira
- Faculty of Medicine, Eduardo Mondlane University, Maputo, Mozambique.,Department of Obstetrics and Gynecology, Maputo Central Hospital, Maputo, Mozambique
| | - Peter Benn
- Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, Connecticut, USA
| |
Collapse
|
11
|
Benn P, Cuckle H, Pergament E. The origins of aneuploidy research consortium. Prenat Diagn 2021; 41:642-646. [PMID: 33720446 DOI: 10.1002/pd.5934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The presence of high levels of aneuploidy in oocytes and early embryos and their fate is of considerable scientific and clinical importance. The Origins of Aneuploidy Research Consortium (OARC) was established to promote interdisciplinary communication and collaborative research into this topic. Under the umbrella of OARC, a series of papers has now been published in this Special Issue of Prenatal Diagnosis. Recent studies have transformed the view that aneuploidy is usually attributable to meiotic non-disjunction. The molecular basis for the association between meiotic error and maternal age is becoming understood. The clinical significance of mitotic instability in the earliest cells divisions of the embryo is also becoming clearer. An error in the segregation of one or more whole chromosomes from a parent does not invariably result in a non-viable pregnancy or an abnormal outcome. Epidemiologic data allows an assessment of in utero viability, the effect of maternal age, and secondary factors that may affect aneuploidy prevalence. We advocate careful use of nomenclature and revision of educational materials to more accurately explain the complex and often nuanced mechanisms. OARC plans to hold additional workshops, promote additional publications and offer educational resources.
Collapse
Affiliation(s)
- Peter Benn
- Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Howard Cuckle
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | |
Collapse
|
12
|
Levy B, Hoffmann ER, McCoy RC, Grati FR. Chromosomal mosaicism: Origins and clinical implications in preimplantation and prenatal diagnosis. Prenat Diagn 2021; 41:631-641. [PMID: 33720449 DOI: 10.1002/pd.5931] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/03/2021] [Accepted: 03/06/2021] [Indexed: 12/18/2022]
Abstract
The diagnosis of chromosomal mosaicism in the preimplantation and prenatal stage is fraught with uncertainty and multiple factors need to be considered in order to gauge the likely impact. The clinical effects of chromosomal mosaicism are directly linked to the type of the imbalance (size, gene content, and copy number), the timing of the initial event leading to mosaicism during embryogenesis/fetal development, the distribution of the abnormal cells throughout the various tissues within the body as well as the ratio of normal/abnormal cells within each of those tissues. Additional factors such as assay noise and culture artifacts also have an impact on the significance and management of mosaic cases. Genetic counseling is an important part of educating patients about the likelihood of having a liveborn with a chromosome abnormality and these risks differ according to the time of ascertainment and the tissue where the mosaic cells were initially discovered. Each situation needs to be assessed on a case-by-case basis and counseled accordingly. This review will discuss the clinical impact of finding mosaicism through: embryo biopsy, chorionic villus sampling, amniocentesis, and noninvasive prenatal testing using cell-free DNA.
Collapse
Affiliation(s)
- Brynn Levy
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York, USA
| | - Eva R Hoffmann
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rajiv C McCoy
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Francesca R Grati
- Research and Development, Cytogenetics and Medical Genetics Unit, TOMA Advanced Biomedical Assays, S.p.A. (Impact Lab), Busto Arsizio, Varese, Italy
| |
Collapse
|
13
|
Cuckle H, Morris J. Maternal age in the epidemiology of common autosomal trisomies. Prenat Diagn 2020; 41:573-583. [PMID: 33078428 DOI: 10.1002/pd.5840] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/04/2020] [Accepted: 10/05/2020] [Indexed: 11/12/2022]
Abstract
The birth prevalence rate of each common autosomal trisomy generally increases with advancing maternal age and there is a substantial fetal loss rate between late first trimester and term. The literature is reviewed in order to provide the best estimates of these rates, taking account where possible of biases due to prenatal diagnosis and selective termination of pregnancy. There is an almost exponential increase in Down syndrome birth prevalence between ages 15 and 45 but at older ages the curve flattens. There is no evidence of the claimed relatively high birth prevalence at extremely low ages. Gestation-specific intra-uterine fetal loss rates are estimated by follow-up of women declining termination of pregnancy after prenatal diagnosis, comparison of observed rates with those expected from birth prevalence and comparison of age-specific curves developed for prenatal diagnosis and birth. Down syndrome fetal loss rates reduce with gestation and increase with maternal age. Edwards and Patau syndrome birth prevalence is approximately 1/8 and 1/13 that of Down syndrome overall, although the ratio differs according to maternal age, particularly for Patau syndrome where it reduces steadily from 1/9 to 1/19. Fetal loss rates are higher for Edwards and Patau syndromes than for Down syndrome.
Collapse
Affiliation(s)
| | - Joan Morris
- Population Health Research Institute, St George's Hospital, UK
| |
Collapse
|