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Fiorentino D, Dar P. Prenatal Screening for Microdeletions and Rare Autosomal Aneuploidies. Clin Obstet Gynecol 2023; 66:579-594. [PMID: 37438896 DOI: 10.1097/grf.0000000000000799] [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
Noninvasive prenatal screening with cell-free DNA is now considered a first-line screening for common aneuploidies. Advancements in existing laboratory techniques now allow to interrogate the entirety of the fetal genome, and many commercial laboratories have expanded their screening panels to include screening for rare autosomal aneuploidies and copy number variants. Here, we review the currently available data on the performance of fetal cell-free DNA to detect rare autosomal aneuploidies and copy number variants that are associated with clinically significant microdeletion and microduplication syndromes and the current position of medical societies on routine screening for these syndromes.
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Affiliation(s)
- Desiree Fiorentino
- Division of Fetal Medicine, Department of Obstetrics and Gynecology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York
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Eggermann T, Monk D, de Nanclares GP, Kagami M, Giabicani E, Riccio A, Tümer Z, Kalish JM, Tauber M, Duis J, Weksberg R, Maher ER, Begemann M, Elbracht M. Imprinting disorders. Nat Rev Dis Primers 2023; 9:33. [PMID: 37386011 DOI: 10.1038/s41572-023-00443-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/19/2023] [Indexed: 07/01/2023]
Abstract
Imprinting disorders (ImpDis) are congenital conditions that are characterized by disturbances of genomic imprinting. The most common individual ImpDis are Prader-Willi syndrome, Angelman syndrome and Beckwith-Wiedemann syndrome. Individual ImpDis have similar clinical features, such as growth disturbances and developmental delay, but the disorders are heterogeneous and the key clinical manifestations are often non-specific, rendering diagnosis difficult. Four types of genomic and imprinting defect (ImpDef) affecting differentially methylated regions (DMRs) can cause ImpDis. These defects affect the monoallelic and parent-of-origin-specific expression of imprinted genes. The regulation within DMRs as well as their functional consequences are mainly unknown, but functional cross-talk between imprinted genes and functional pathways has been identified, giving insight into the pathophysiology of ImpDefs. Treatment of ImpDis is symptomatic. Targeted therapies are lacking owing to the rarity of these disorders; however, personalized treatments are in development. Understanding the underlying mechanisms of ImpDis, and improving diagnosis and treatment of these disorders, requires a multidisciplinary approach with input from patient representatives.
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Affiliation(s)
- Thomas Eggermann
- Institute for Human Genetics and Genomic Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany.
| | - David Monk
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - Guiomar Perez de Nanclares
- Rare Diseases Research Group, Molecular (Epi)Genetics Laboratory, Bioaraba Research Health Institute, Araba University Hospital-Txagorritxu, Vitoria-Gasteiz, Spain
| | - Masayo Kagami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Eloïse Giabicani
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, APHP, Hôpital Armand Trousseau, Endocrinologie Moléculaire et Pathologies d'Empreinte, Paris, France
| | - Andrea Riccio
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Università della Campania Luigi Vanvitelli, Caserta, Italy
- Institute of Genetics and Biophysics A. Buzzati-Traverso, CNR, Naples, Italy
| | - Zeynep Tümer
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jennifer M Kalish
- Division of Human Genetics and Center for Childhood Cancer Research, Children's Hospital of Philadelphia and the Departments of Pediatrics and Genetics at the Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Maithé Tauber
- Centre de Référence Maladies Rares PRADORT (syndrome de PRADer-Willi et autres Obésités Rares avec Troubles du comportement alimentaire), Hôpital des Enfants, CHU Toulouse, Toulouse, France
- Institut Toulousain des Maladies Infectieuses et Inflammatoires (Infinity) INSERM UMR1291 - CNRS UMR5051 - Université Toulouse III, Toulouse, France
| | - Jessica Duis
- Department of Pediatrics, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Rosanna Weksberg
- Division of Clinical and Metabolic Genetics, Department of Paediatrics and Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Sciences and Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Eamonn R Maher
- Department of Medical Genetics, University of Cambridge, Cambridge, UK
| | - Matthias Begemann
- Institute for Human Genetics and Genomic Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Miriam Elbracht
- Institute for Human Genetics and Genomic Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany
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Prenatal Diagnosis of Uniparental Disomy in Cases of Rare Autosomal Trisomies Detected Using Noninvasive Prenatal Test: A Case of Prader-Willi Syndrome. Diagnostics (Basel) 2023; 13:diagnostics13040580. [PMID: 36832068 PMCID: PMC9955094 DOI: 10.3390/diagnostics13040580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/09/2023] Open
Abstract
Rare autosomal trisomies (RATs) other than common aneuploidies can be detected using noninvasive prenatal testing (NIPT). However, conventional karyotyping is insufficient for evaluating diploid fetuses with uniparental disomy (UPD) due to trisomy rescue. Using the diagnostic process for Prader-Willi syndrome (PWS), we aim to describe the need for additional prenatal diagnostic testing for confirming UPD in fetuses diagnosed with RATs via NIPT and its clinical implications. NIPT was performed using the massively parallel sequencing (MPS) method, and all pregnant women with RATs underwent amniocentesis. After confirming the normal karyotype, short tandem repeat (STR) analysis, methylation-specific PCR (MS-PCR), and methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) were performed to detect UPD. Overall, six cases were diagnosed with RATs. There was a suspicion of trisomies of chromosomes 7, 8, and 15 in two cases each. However, these cases were confirmed to have a normal karyotype using amniocentesis. In one of six cases, PWS caused by maternal UPD 15 was diagnosed using MS-PCR and MS-MLPA. We propose that in cases where RAT is detected by NIPT, UPD should be considered following trisomy rescue. Even if amniocentesis confirms a normal karyotype, UPD testing (such as MS-PCR and MS-MLPA) should be recommended for accurate assessment, as an accurate diagnosis can lead to appropriate genetic counseling and improved overall pregnancy management.
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Zuffardi O, Fichera M, Bonaglia MC. The embryo battle against adverse genomes: Are de novo terminal deletions the rescue of unfavorable zygotic imbalances? Eur J Med Genet 2022; 65:104532. [PMID: 35724817 DOI: 10.1016/j.ejmg.2022.104532] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 04/02/2022] [Accepted: 05/21/2022] [Indexed: 11/03/2022]
Abstract
De novo distal deletions are structural variants considered to be already present in the zygote. However, investigations especially in the prenatal setting have documented that they are often in mosaic with cell lines in which the same deleted chromosome shows different types of aberrations such as: 1) neutral copy variants with loss of heterozygosity that replace the deleted region with equivalent portions of the homologous chromosome and create distal uniparental disomy (UPD); 2) derivative chromosomes where the deleted one ends with the distal region of another chromosome or has the shape of a ring; 3) U-type mirror dicentric or inv-dup del rearrangements. Unstable dicentrics had already been entailed as causative of terminal deletions even when no trace of the reciprocal inv-dup del had been detected. To clarify the mechanism of origin of distal deletions, we examined PubMed using as keywords: complex/mosaic chromosomal deletions, distal UPD, U-type dicentrics, inv-dup del chromosomes, excluding the recurrent inv-dup del(8p)s which are known to originate by NAHR at the maternal meiosis. The literature has shown that U-type dicentrics leading to nearly complete trisomy and therefore incompatible with zygotic survival underlie many types of de novo unbalanced rearrangements, including terminal deletions. In the early embryo, the position of the postzygotic breaks of the dicentric, the different ways of acquiring telomeres by the broken portions and the selection of the most favorable cell lines in the different tissues determine the prevalence of one or the other rearrangement. Multiple lines with simple terminal deletions, inv-dup dels, unbalanced translocations and segmental UPDs can coexist in various mosaic combinations although it is rare to identify them all in the blood. Regarding the origin of the dicentric, among the 30 cases of non-recurrent inv-dup del with sufficient genotyping information, paternal origin was markedly prevalent with consistently identical polymorphisms within the duplication region, regardless of parental origin. The non-random parental origin made any postzygotic origin unlikely and suggested the occurrence of these dicentrics mainly in spermatogenesis. This study strengthens the evidence that non-recurrent de novo structural rearrangements are often secondary to the rescue of a zygotic genome incompatible with embryo survival.
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Affiliation(s)
- Orsetta Zuffardi
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.
| | - Marco Fichera
- Department of Biomedical and Biotechnological Sciences, Medical Genetics, University of Catania, Catania, Italy; Oasi Research Institute-IRCCS, Troina, Italy.
| | - Maria Clara Bonaglia
- Cytogenetics Laboratory, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy.
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Okuda T, Moroto M, Yamamoto T. Noninvasive prenatal testing suggesting an abnormality in chromosome 15 confirmed to be a case of Prader-Willi syndrome caused by trisomy rescue in the neonatal period. J Obstet Gynaecol Res 2022; 48:2214-2218. [PMID: 35322506 DOI: 10.1111/jog.15236] [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: 09/06/2021] [Revised: 01/14/2022] [Accepted: 03/14/2022] [Indexed: 11/29/2022]
Abstract
We report a case of a neonatal diagnosis of Prader-Willi syndrome caused by uniparental disomy. A 34-year-old pregnant woman underwent noninvasive prenatal testing (NIPT) in a hospital that was not certified by the Japanese Association of Medical Sciences. The results of trisomy 13, 18, and 21 were negative; however, a possible abnormality in chromosome 15 was indicated by the Z-score. Genetic counseling was not performed; thus, the woman did not understand the implication of this result. Therefore, she continued with the pregnancy and delivered a boy weighing 1892 g with hypogonadism at 38 weeks and 5 days. The infant was diagnosed with Prader-Willi syndrome caused by uniparental disomy derived from trisomy rescue. The NIPT results may have reflected placental mosaicism, emphasizing the importance of understanding the limitations of NIPT due to the presence of congenital chromosomal abnormalities that cannot be detected by NIPT platforms.
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Affiliation(s)
- Tomohiro Okuda
- Department of Obstetrics and Gynecology, Fukuchiyama City Hospital, Fukuchiyama City, Kyoto, Japan
| | - Masaharu Moroto
- Department of Pediatrics, Fukuchiyama City Hospital, Fukuchiyama City, Kyoto, Japan
| | - Toshiyuki Yamamoto
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
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Papenhausen PR, Kelly CA, Harris S, Caldwell S, Schwartz S, Penton A. Clinical significance and mechanisms associated with segmental UPD. Mol Cytogenet 2021; 14:38. [PMID: 34284807 PMCID: PMC8290618 DOI: 10.1186/s13039-021-00555-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/22/2021] [Indexed: 11/14/2022] Open
Abstract
Whole chromosome uniparental disomy (UPD) has been well documented with mechanisms largely understood. However, the etiology of segmental limited UPD (segUPD) is not as clear. In a 10-year period of confirming (> 300) cases of whole chromosome UPD, we identified 86 segmental cases in both prenatal and postnatal samples. Thirty-two of these cases showed mosaic segmental UPD at 11p due to somatic selection associated with Beckwith–Wiedemann syndrome. This study focuses on apparent mechanisms associated with the remaining cases, many of which appear to represent corrections of genomic imbalance such as deletions and derivative chromosomes. In some cases, segmental UPD was associated with the generation of additional genomic imbalance while in others it apparently resulted in restoration of euploidy. Multiple tests utilizing noninvasive prenatal testing (NIPT), chorionic villus sampling (CVS) and amniotic fluid samples from the same pregnancy revealed temporal evidence of correction and a “hotspot” at 1p. Although in many cases the genomic imbalance was dosage “repaired” in the analyzed tissue, clinical effects could be sustained due to early developmental effects of the original imbalance or due to its continued existence in other tissues. In addition, if correction did not occur in the gametes there would be recurrence risks for the offspring of those individuals. Familial microarray allele patterns are presented that differentiate lack of gamete correction from somatic derived gonadal mosaicism. These results suggest that the incidence of segUPD mediated correction is underestimated and may explain the etiology of some clinical phenotypes which are undetected by routine microarray analysis and many exome sequencing studies.
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Affiliation(s)
- Peter R Papenhausen
- Cytogenetics Department, Laboratory Corporation of America, Research Triangle Park, NC, 27709, USA
| | - Carla A Kelly
- Cytogenetics Department, Laboratory Corporation of America, Research Triangle Park, NC, 27709, USA
| | - Samuel Harris
- Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Samantha Caldwell
- Cytogenetics Department, Laboratory Corporation of America, Research Triangle Park, NC, 27709, USA
| | - Stuart Schwartz
- Cytogenetics Department, Laboratory Corporation of America, Research Triangle Park, NC, 27709, USA
| | - Andrea Penton
- Cytogenetics Department, Laboratory Corporation of America, Research Triangle Park, NC, 27709, USA.
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Genome-wide cell-free DNA screening: a focus on copy-number variants. Genet Med 2021; 23:1847-1853. [PMID: 34155363 PMCID: PMC8486654 DOI: 10.1038/s41436-021-01227-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/12/2021] [Accepted: 05/13/2021] [Indexed: 11/16/2022] Open
Abstract
Purpose Of 86,902 prenatal genome-wide cell-free DNA (cfDNA) screening tests, 4,121 were positive for a chromosome abnormality. This study examines 490 cases screen-positive for one or more subchromosomal copy-number variants (CNV) from genome-wide cfDNA screening. Methods Cases positive for one or more subchromosomal CNV from genome-wide cfDNA screening and diagnostic outcomes were compiled. Diagnostic testing trends were analyzed, positive predictive values (PPVs) were calculated, and the type of chromosomal abnormalities ultimately confirmed by diagnostic testing were described. Results CNVs were identified in 0.56% of screened specimens. Of the 490 cases screen-positive for one or more CNV, diagnostic outcomes were available for 244 cases (50%). The overall PPV among the cases with diagnostic outcomes was 74.2% (95% CI: 68.1–79.5%) and 71.8% (95% CI: 65.5–77.4%) for “fetal-only” events. Overall, isolated CNVs showed a lower PPV of 61.0% (95% CI: 52.5–68.8%) compared to complex CNVs at 93.9% (95% CI: 86.6–97.5%). Isolated deletions/duplications and unbalanced structural rearrangements were the most common diagnostic outcomes when isolated and complex CNVs were identified by cfDNA screening, respectively. Conclusion Genome-wide cfDNA screening identifies chromosomal abnormalities beyond the scope of traditional cfDNA screening, and the overall PPV associated with subchromosomal CNVs in cases with diagnostic outcomes was >70%.
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Pang Y, Wang C, Tang J, Zhu J. Clinical application of noninvasive prenatal testing in the detection of fetal chromosomal diseases. Mol Cytogenet 2021; 14:31. [PMID: 34127051 PMCID: PMC8204420 DOI: 10.1186/s13039-021-00550-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 05/27/2021] [Indexed: 01/12/2023] Open
Abstract
Objective To assess the detection efficiency of noninvasive prenatal testing (NIPT) for fetal autosomal aneuploidy, sex chromosome aneuploidy (SCA), other chromosome aneuploidy, copy number variation (CNV), and to provide further data for clinical application of NIPT. Materials and methods 25,517 pregnant women who underwent NIPT testing in Anhui Province Maternity and Child Health Hospital from September 2019 to September 2020 were selected, and samples with high-risk test results were subjected to karyotype analysis for comparison by using amniotic fluid, with some samples subjected to further validation by chromosomal microarray analysis, and followed up for pregnancy outcome. Results A total of 25,517 pregnant women who received NIPT, 25,502 cases were tested successfully, and 294 high-risk samples (1.15%) were detected, there were 96 true positive samples, 117 false positive samples and 81 cases were refused further diagnosis. Samples with high risk of autosomal aneuploidy were detected in 71 cases (0.28%), and 51 cases were confirmed, including: trisomy 21 (T21) in 44 cases, trisomy 18 (T18) in 5 cases, and trisomy 13 (T13) in 2 cases; the positive predictive value (PPV) was 91.67%, 45.45%, and 33.33%, respectively, and the negative predictive value was 100%, the false positive rate (FPR) was 0.02%, 0.02%, and 0.02%, respectively.13 samples with high risk of mosaic trisomies 21, 18, and 13 were detected, and 1 case of T21mos was confirmed with a PPV of 8.33%. Samples with high risk of SCA were detected in 72 cases (0.28%), and the diagnosis was confirmed in 23 cases, with a PPV of 41.07% and a FPR of 0.13%. These included 3 cases of 45,X, 6 cases of 47,XXY, 8 cases of 47,XXX and 6 cases of 47,XYY, with PPVs of 12.00%, 50.00%, 72.73%, and 75.00%, respectively, and false-positive rates of 0.09%, 0.02%, 0.01% and 0.01% respectively. Samples with high risk of CNV were detected in 104 cases (0.41%) and confirmed in 18 cases, with a PPV of 32.14% and a FPR of 0.15%. Samples with high risk of other chromosomal aneuploidy were detected in 34 cases (0.13%), and the diagnosis was confirmed in 3 cases, which were T2, T9, and T16 respectively. The overall PPV for other chromosome aneuploidy was 12.50%, with a FPR of 0.08%. Conclusion NIPT is indicated for trisomies 21, 18 and 13 screening, especially for T21. It also has some certain reference value for SCA and CNV, but is not recommended for screening of other chromosomal aneuploidy.
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Affiliation(s)
- Yu Pang
- Affiliated Maternity and Child Health Hospital of Anhui Medical University, Hefei, China.,Maternity and Child Health Hospital of Anhui Province, Hefei, China
| | - Chaohong Wang
- Maternity and Child Health Hospital of Anhui Province, Hefei, China
| | - Junxiang Tang
- Maternity and Child Health Hospital of Anhui Province, Hefei, China
| | - Jiansheng Zhu
- Affiliated Maternity and Child Health Hospital of Anhui Medical University, Hefei, China. .,Maternity and Child Health Hospital of Anhui Province, Hefei, China.
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