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Nepomuceno TC, Lyra P, Zhu J, Yi F, Martin RH, Lupu D, Peterson L, Peres LC, Berry A, Iversen ES, Couch FJ, Mo Q, Monteiro AN. Assessment of BRCA1 and BRCA2 Germline Variant Data From Patients With Breast Cancer in a Real-World Data Registry. JCO Clin Cancer Inform 2024; 8:e2300251. [PMID: 38709234 PMCID: PMC11161245 DOI: 10.1200/cci.23.00251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 02/12/2024] [Accepted: 03/13/2024] [Indexed: 05/07/2024] Open
Abstract
PURPOSE The emergence of large real-world clinical databases and tools to mine electronic medical records has allowed for an unprecedented look at large data sets with clinical and epidemiologic correlates. In clinical cancer genetics, real-world databases allow for the investigation of prevalence and effectiveness of prevention strategies and targeted treatments and for the identification of barriers to better outcomes. However, real-world data sets have inherent biases and problems (eg, selection bias, incomplete data, measurement error) that may hamper adequate analysis and affect statistical power. METHODS Here, we leverage a real-world clinical data set from a large health network for patients with breast cancer tested for variants in BRCA1 and BRCA2 (N = 12,423). We conducted data cleaning and harmonization, cross-referenced with publicly available databases, performed variant reassessment and functional assays, and used functional data to inform a variant's clinical significance applying American College of Medical Geneticists and the Association of Molecular Pathology guidelines. RESULTS In the cohort, White and Black patients were over-represented, whereas non-White Hispanic and Asian patients were under-represented. Incorrect or missing variant designations were the most significant contributor to data loss. While manual curation corrected many incorrect designations, a sizable fraction of patient carriers remained with incorrect or missing variant designations. Despite the large number of patients with clinical significance not reported, original reported clinical significance assessments were accurate. Reassessment of variants in which clinical significance was not reported led to a marked improvement in data quality. CONCLUSION We identify the most common issues with BRCA1 and BRCA2 testing data entry and suggest approaches to minimize data loss and keep interpretation of clinical significance of variants up to date.
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Affiliation(s)
- Thales C. Nepomuceno
- Department of Cancer Epidemiology Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL
| | - Paulo Lyra
- Department of Cancer Epidemiology Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL
| | - Jianbin Zhu
- AdventHealth Research Institute, Orlando, FL
| | - Fanchao Yi
- AdventHealth Research Institute, Orlando, FL
| | - Rachael H. Martin
- Department of Cancer Epidemiology Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL
| | | | | | - Lauren C. Peres
- Department of Cancer Epidemiology Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL
| | - Anna Berry
- AdventHealth Cancer Institute, Orlando, FL
| | | | | | - Qianxing Mo
- Department of Biostatistics and Bioinformatics, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL
| | - Alvaro N. Monteiro
- Department of Cancer Epidemiology Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL
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2
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Filser M, Schwartz M, Merchadou K, Hamza A, Villy MC, Decees A, Frouin E, Girard E, Caputo SM, Renault V, Becette V, Golmard L, Servant N, Stoppa-Lyonnet D, Delattre O, Colas C, Masliah-Planchon J. Adaptive nanopore sequencing to determine pathogenicity of BRCA1 exonic duplication. J Med Genet 2023; 60:1206-1209. [PMID: 37263769 DOI: 10.1136/jmg-2023-109155] [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: 01/11/2023] [Accepted: 04/30/2023] [Indexed: 06/03/2023]
Abstract
BRCA1 and BRCA2 are tumour suppressor genes that have been characterised as predisposition genes for the development of hereditary breast and ovarian cancers among other malignancies. The molecular diagnosis of this predisposition syndrome is based on the detection of inactivating variants of any type in those genes. But in the case of structural variants, functional consequences can be difficult to assess using standard molecular methods, as the precise resolution of their sequence is often impossible with short-read next generation sequencing techniques. It has been recently demonstrated that Oxford Nanopore long-read sequencing technology can accurately and rapidly provide genetic diagnoses of Mendelian diseases, including those linked to pathogenic structural variants. Here, we report the accurate resolution of a germline duplication event of exons 18-20 of BRCA1 using Nanopore sequencing with adaptive sampling target enrichment. This allowed us to classify this variant as pathogenic within a short timeframe of 10 days. This study provides a proof-of-concept that nanopore adaptive sampling is a highly efficient technique for the investigation of structural variants of tumour suppressor genes in a clinical context.
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Affiliation(s)
- Mathilde Filser
- Genetics Department, Institut Curie, Paris, France
- PSL Research University, Paris, France
| | - Mathias Schwartz
- Genetics Department, Institut Curie, Paris, France
- PSL Research University, Paris, France
| | - Kevin Merchadou
- PSL Research University, Paris, France
- Clinical Bioinformatics Unit, Institut Curie, Paris, France
| | - Abderaouf Hamza
- Genetics Department, Institut Curie, Paris, France
- PSL Research University, Paris, France
| | - Marie-Charlotte Villy
- Oncogenetic Clinic Unit, Institut Curie, Paris, France
- SIREDO Oncology Centre, Institut Curie, Paris, France
| | - Antoine Decees
- Genetics Department, Institut Curie, Paris, France
- PSL Research University, Paris, France
| | - Eléonore Frouin
- PSL Research University, Paris, France
- Clinical Bioinformatics Unit, Institut Curie, Paris, France
| | - Elodie Girard
- PSL Research University, Paris, France
- INSERM U900, Institut Curie, Paris, France
| | - Sandrine M Caputo
- Genetics Department, Institut Curie, Paris, France
- PSL Research University, Paris, France
| | - Victor Renault
- PSL Research University, Paris, France
- Clinical Bioinformatics Unit, Institut Curie, Paris, France
| | - Véronique Becette
- PSL Research University, Paris, France
- Anatomo- and Cyto-pathology, Institut Curie, Saint-Cloud, France
| | - Lisa Golmard
- Genetics Department, Institut Curie, Paris, France
- PSL Research University, Paris, France
| | - Nicolas Servant
- PSL Research University, Paris, France
- INSERM U900, Institut Curie, Paris, France
| | - Dominique Stoppa-Lyonnet
- Genetics Department, Institut Curie, Paris, France
- SIREDO Oncology Centre, Institut Curie, Paris, France
| | - Olivier Delattre
- Genetics Department, Institut Curie, Paris, France
- Inserm U830, PSL University, Research Center, Institut Curie, Paris, France
| | - Chrystelle Colas
- PSL Research University, Paris, France
- Oncogenetic Clinic Unit, Institut Curie, Paris, France
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3
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Dixon K, Shen Y, O'Neill K, Mungall KL, Chan S, Bilobram S, Zhang W, Bezeau M, Sharma A, Fok A, Mungall AJ, Moore R, Bosdet I, Thibodeau ML, Sun S, Yip S, Schrader KA, Jones SJM. Defining the heterogeneity of unbalanced structural variation underlying breast cancer susceptibility by nanopore genome sequencing. Eur J Hum Genet 2023; 31:602-606. [PMID: 36797466 PMCID: PMC10172360 DOI: 10.1038/s41431-023-01284-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 12/23/2022] [Accepted: 01/10/2023] [Indexed: 02/18/2023] Open
Abstract
Germline structural variants (SVs) are challenging to resolve by conventional genetic testing assays. Long-read sequencing has improved the global characterization of SVs, but its sensitivity at cancer susceptibility loci has not been reported. Nanopore long-read genome sequencing was performed for nineteen individuals with pathogenic copy number alterations in BRCA1, BRCA2, CHEK2 and PALB2 identified by prior clinical testing. Fourteen variants, which spanned single exons to whole genes and included a tandem duplication, were accurately represented. Defining the precise breakpoints of SVs in BRCA1 and CHEK2 revealed unforeseen allelic heterogeneity and informed the mechanisms underlying the formation of recurrent deletions. Integrating read-based and statistical phasing further helped define extended haplotypes associated with founder alleles. Long-read sequencing is a sensitive method for characterizing private, recurrent and founder SVs underlying breast cancer susceptibility. Our findings demonstrate the potential for nanopore sequencing as a powerful genetic testing assay in the hereditary cancer setting.
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Affiliation(s)
- Katherine Dixon
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada
| | - Yaoqing Shen
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada
| | - Kieran O'Neill
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada
| | - Karen L Mungall
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada
| | - Simon Chan
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada
| | - Steve Bilobram
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada
| | - Wei Zhang
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada
| | | | | | - Alexandra Fok
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada.,Hereditary Cancer Program, BC Cancer, Vancouver, BC, Canada
| | - Andrew J Mungall
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada
| | - Richard Moore
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada
| | - Ian Bosdet
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - My Linh Thibodeau
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada.,Hereditary Cancer Program, BC Cancer, Vancouver, BC, Canada
| | - Sophie Sun
- Hereditary Cancer Program, BC Cancer, Vancouver, BC, Canada.,Department of Medical Oncology, BC Cancer, Vancouver, BC, Canada
| | - Stephen Yip
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Kasmintan A Schrader
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada. .,Hereditary Cancer Program, BC Cancer, Vancouver, BC, Canada.
| | - Steven J M Jones
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada. .,Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada.
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Thomassen M, Mesman RLS, Hansen TVO, Menendez M, Rossing M, Esteban‐Sánchez A, Tudini E, Törngren T, Parsons MT, Pedersen IS, Teo SH, Kruse TA, Møller P, Borg Å, Jensen UB, Christensen LL, Singer CF, Muhr D, Santamarina M, Brandao R, Andresen BS, Feng B, Canson D, Richardson ME, Karam R, Pesaran T, LaDuca H, Conner BR, Abualkheir N, Hoang L, Calléja FMGR, Andrews L, James PA, Bunyan D, Hamblett A, Radice P, Goldgar DE, Walker LC, Engel C, Claes KBM, Macháčková E, Baralle D, Viel A, Wappenschmidt B, Lazaro C, Vega A, Vreeswijk MPG, de la Hoya M, Spurdle AB. Clinical, splicing, and functional analysis to classify BRCA2 exon 3 variants: Application of a points-based ACMG/AMP approach. Hum Mutat 2022; 43:1921-1944. [PMID: 35979650 PMCID: PMC10946542 DOI: 10.1002/humu.24449] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 08/05/2022] [Accepted: 08/09/2022] [Indexed: 01/25/2023]
Abstract
Skipping of BRCA2 exon 3 (∆E3) is a naturally occurring splicing event, complicating clinical classification of variants that may alter ∆E3 expression. This study used multiple evidence types to assess pathogenicity of 85 variants in/near BRCA2 exon 3. Bioinformatically predicted spliceogenic variants underwent mRNA splicing analysis using minigenes and/or patient samples. ∆E3 was measured using quantitative analysis. A mouse embryonic stem cell (mESC) based assay was used to determine the impact of 18 variants on mRNA splicing and protein function. For each variant, population frequency, bioinformatic predictions, clinical data, and existing mRNA splicing and functional results were collated. Variant class was assigned using a gene-specific adaptation of ACMG/AMP guidelines, following a recently proposed points-based system. mRNA and mESC analysis combined identified six variants with transcript and/or functional profiles interpreted as loss of function. Cryptic splice site use for acceptor site variants generated a transcript encoding a shorter protein that retains activity. Overall, 69/85 (81%) variants were classified using the points-based approach. Our analysis shows the value of applying gene-specific ACMG/AMP guidelines using a points-based approach and highlights the consideration of cryptic splice site usage to appropriately assign PVS1 code strength.
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Affiliation(s)
- Mads Thomassen
- Department of Clinical GeneticsOdense University HospitalOdence CDenmark
| | - Romy L. S. Mesman
- Department of Human GeneticsLeiden University Medical CenterLeidenthe Netherlands
| | - Thomas V. O. Hansen
- Department of Clinical Genetics, RigshospitaletCopenhagen University HospitalCopenhagenDenmark
| | - Mireia Menendez
- Hereditary Cancer ProgramCatalan Institute of Oncology, ONCOBELL‐IDIBELL‐IDTP, CIBERONCHospitalet de LlobregatSpain
| | - Maria Rossing
- Center for Genomic Medicine, RigshospitaletCopenhagen University HospitalCopenhagenDenmark
| | - Ada Esteban‐Sánchez
- Molecular Oncology Laboratory, CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos)MadridSpain
| | - Emma Tudini
- Department of Genetics and Computational BiologyQIMR Berghofer Medical Research InstituteBrisbaneQueenslandAustralia
| | - Therese Törngren
- Division of Oncology, Department of Clinical Sciences LundLund UniversityLundSweden
| | - Michael T. Parsons
- Department of Genetics and Computational BiologyQIMR Berghofer Medical Research InstituteBrisbaneQueenslandAustralia
| | - Inge S. Pedersen
- Molecular Diagnostics, Aalborg University HospitalAalborgDenmark
- Clinical Cancer Research CenterAalborg University HospitalAalborgDenmark
- Department of Clinical MedicineAalborg UniversityAalborgDenmark
| | - Soo H. Teo
- Breast Cancer Research ProgrammeCancer Research MalaysiaSubang JayaSelangorMalaysia
- Department of Surgery, Faculty of MedicineUniversity of MalayaKuala LumpurMalaysia
| | - Torben A. Kruse
- Department of Clinical GeneticsOdense University HospitalOdence CDenmark
| | - Pål Møller
- Department of Tumour BiologyThe Norwegian Radium Hospital, Oslo University HospitalOsloNorway
| | - Åke Borg
- Division of Oncology, Department of Clinical Sciences LundLund UniversityLundSweden
| | - Uffe B. Jensen
- Department of Clinical GeneticsAarhus University HospitalAarhus NDenmark
| | | | - Christian F. Singer
- Department of OB/GYN and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
| | - Daniela Muhr
- Department of OB/GYN and Comprehensive Cancer CenterMedical University of ViennaViennaAustria
| | - Marta Santamarina
- Fundación Pública Galega de Medicina XenómicaSantiago de CompostelaSpain
- Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complejo Hospitalario Universitario de Santiago, SERGASSantiago de CompostelaSpain
- Centro de Investigación en Red de Enfermedades Raras (CIBERER)MadridSpain
| | - Rita Brandao
- Department of Clinical GeneticsMaastricht University Medical CenterMaastrichtthe Netherlands
| | - Brage S. Andresen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical SciencesUniversity of Southern DenmarkOdenseDenmark
| | - Bing‐Jian Feng
- Department of DermatologyHuntsman Cancer Institute, University of Utah School of MedicineSalt Lake CityUtahUSA
| | - Daffodil Canson
- Department of Genetics and Computational BiologyQIMR Berghofer Medical Research InstituteBrisbaneQueenslandAustralia
| | | | | | | | | | | | | | | | | | - Lesley Andrews
- Hereditary Cancer Clinic, Nelune Comprehensive Cancer Care CentreSydneyNew South WalesAustralia
| | - Paul A. James
- Parkville Familial Cancer Centre, Peter MacCallum Cancer CenterMelbourneVictoriaAustralia
- Sir Peter MacCallum Department of OncologyThe University of MelbourneMelbourneVictoriaAustralia
| | - Dave Bunyan
- Human Development and Health, Faculty of MedicineUniversity of SouthamptonSouthamptonUK
| | - Amanda Hamblett
- Middlesex Health Shoreline Cancer CenterWestbrookConnecticutUSA
| | - Paolo Radice
- Unit of Molecular Bases of Genetic Risk and Genetic Testing, Department of ResearchFondazione IRCCS Istituto Nazionale dei Tumori (INT)MilanItaly
| | - David E. Goldgar
- Department of DermatologyHuntsman Cancer Institute, University of Utah School of MedicineSalt Lake CityUtahUSA
| | - Logan C. Walker
- Department of Pathology and Biomedical ScienceUniversity of OtagoChristchurchNew Zealand
| | - Christoph Engel
- Institute for Medical Informatics, Statistics and EpidemiologyUniversity of LeipzigLeipzigGermany
| | | | - Eva Macháčková
- Department of Cancer Epidemiology and GeneticsMasaryk Memorial Cancer InstituteBrnoCzech Republic
| | - Diana Baralle
- Human Development and Health, Faculty of MedicineUniversity of SouthamptonSouthamptonUK
| | - Alessandra Viel
- Division of Functional Onco‐genomics and GeneticsCentro di Riferimento Oncologico di Aviano (CRO), IRCCSAvianoItaly
| | - Barbara Wappenschmidt
- Center for Familial Breast and Ovarian Cancer, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
- Center for Integrated Oncology (CIO), Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Conxi Lazaro
- Hereditary Cancer ProgramCatalan Institute of Oncology, ONCOBELL‐IDIBELL‐IDTP, CIBERONCHospitalet de LlobregatSpain
| | - Ana Vega
- Fundación Pública Galega de Medicina XenómicaSantiago de CompostelaSpain
- Instituto de Investigación Sanitaria de Santiago de Compostela (IDIS), Complejo Hospitalario Universitario de Santiago, SERGASSantiago de CompostelaSpain
- Centro de Investigación en Red de Enfermedades Raras (CIBERER)MadridSpain
| | - ENIGMA Consortium
- Department of Genetics and Computational BiologyQIMR Berghofer Medical Research InstituteBrisbaneQueenslandAustralia
| | | | - Miguel de la Hoya
- Molecular Oncology Laboratory, CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos)MadridSpain
| | - Amanda B. Spurdle
- Department of Genetics and Computational BiologyQIMR Berghofer Medical Research InstituteBrisbaneQueenslandAustralia
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5
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Value of the loss of heterozygosity to BRCA1 variant classification. NPJ Breast Cancer 2022; 8:9. [PMID: 35039532 PMCID: PMC8764043 DOI: 10.1038/s41523-021-00361-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 09/21/2021] [Indexed: 11/25/2022] Open
Abstract
At least 10% of the BRCA1/2 tests identify variants of uncertain significance (VUS) while the distinction between pathogenic variants (PV) and benign variants (BV) remains particularly challenging. As a typical tumor suppressor gene, the inactivation of the second wild-type (WT) BRCA1 allele is expected to trigger cancer initiation. Loss of heterozygosity (LOH) of the WT allele is the most frequent mechanism for the BRCA1 biallelic inactivation. To evaluate if LOH can be an effective predictor of BRCA1 variant pathogenicity, we carried out LOH analysis on DNA extracted from 90 breast and seven ovary tumors diagnosed in 27 benign and 55 pathogenic variant carriers. Further analyses were conducted in tumors with PVs yet without loss of the WT allele: BRCA1 promoter hypermethylation, next-generation sequencing (NGS) of BRCA1/2, and BRCAness score. Ninety-seven tumor samples were analyzed from 26 different BRCA1 variants. A relatively stable pattern of LOH (65.4%) of WT allele for PV tumors was observed, while the allelic balance (63%) or loss of variant allele (15%) was generally seen for carriers of BV. LOH data is a useful complementary argument for BRCA1 variant classification.
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6
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Caputo SM, Golmard L, Léone M, Damiola F, Guillaud-Bataille M, Revillion F, Rouleau E, Derive N, Buisson A, Basset N, Schwartz M, Vilquin P, Garrec C, Privat M, Gay-Bellile M, Abadie C, Abidallah K, Airaud F, Allary AS, Barouk-Simonet E, Belotti M, Benigni C, Benusiglio PR, Berthemin C, Berthet P, Bertrand O, Bézieau S, Bidart M, Bignon YJ, Birot AM, Blanluet M, Bloucard A, Bombled J, Bonadona V, Bonnet F, Bonnet-Dupeyron MN, Boulaire M, Boulouard F, Bouras A, Bourdon V, Brahimi A, Brayotel F, Bressac de Paillerets B, Bronnec N, Bubien V, Buecher B, Cabaret O, Carriere J, Chiesa J, Chieze-Valéro S, Cohen C, Cohen-Haguenauer O, Colas C, Collonge-Rame MA, Conoy AL, Coulet F, Coupier I, Crivelli L, Cusin V, De Pauw A, Dehainault C, Delhomelle H, Delnatte C, Demontety S, Denizeau P, Devulder P, Dreyfus H, d’Enghein CD, Dupré A, Durlach A, Dussart S, Fajac A, Fekairi S, Fert-Ferrer S, Fiévet A, Fouillet R, Mouret-Fourme E, Gauthier-Villars M, Gesta P, Giraud S, Gladieff L, Goldbarg V, Goussot V, Guibert V, Guillerm E, Guy C, Hardouin A, Heude C, Houdayer C, Ingster O, Jacquot-Sawka C, Jones N, Krieger S, Lacoste S, Lallaoui H, Larbre H, Laugé A, Le Guyadec G, Le Mentec M, Lecerf C, Le Gall J, Legendre B, Legrand C, Legros A, Lejeune S, Lidereau R, Lignon N, Limacher JM, Doriane Livon, Lizard S, Longy M, Lortholary A, Macquere P, Mailliez A, Malsa S, Margot H, Mari V, Maugard C, Meira C, Menjard J, Molière D, Moncoutier V, Moretta-Serra J, Muller E, Nevière Z, Nguyen Minh Tuan TV, Noguchi T, Noguès C, Oca F, Popovici C, Prieur F, Raad S, Rey JM, Ricou A, Salle L, Saule C, Sevenet N, Simaga F, Sobol H, Suybeng V, Tennevet I, Tenreiro H, Tinat J, Toulas C, Turbiez I, Uhrhammer N, Vande Perre P, Vaur D, Venat L, Viellard N, Villy MC, Warcoin M, Yvard A, Zattara H, Caron O, Lasset C, Remenieras A, Boutry-Kryza N, Castéra L, Stoppa-Lyonnet D. Classification of 101 BRCA1 and BRCA2 variants of uncertain significance by cosegregation study: A powerful approach. Am J Hum Genet 2021; 108:1907-1923. [PMID: 34597585 DOI: 10.1016/j.ajhg.2021.09.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/01/2021] [Indexed: 12/18/2022] Open
Abstract
Up to 80% of BRCA1 and BRCA2 genetic variants remain of uncertain clinical significance (VUSs). Only variants classified as pathogenic or likely pathogenic can guide breast and ovarian cancer prevention measures and treatment by PARP inhibitors. We report the first results of the ongoing French national COVAR (cosegregation variant) study, the aim of which is to classify BRCA1/2 VUSs. The classification method was a multifactorial model combining different associations between VUSs and cancer, including cosegregation data. At this time, among the 653 variants selected, 101 (15%) distinct variants shared by 1,624 families were classified as pathogenic/likely pathogenic or benign/likely benign by the COVAR study. Sixty-six of the 101 (65%) variants classified by COVAR would have remained VUSs without cosegregation data. Of note, among the 34 variants classified as pathogenic by COVAR, 16 remained VUSs or likely pathogenic when following the ACMG/AMP variant classification guidelines. Although the initiation and organization of cosegregation analyses require a considerable effort, the growing number of available genetic tests results in an increasing number of families sharing a particular variant, and thereby increases the power of such analyses. Here we demonstrate that variant cosegregation analyses are a powerful tool for the classification of variants in the BRCA1/2 breast-ovarian cancer predisposition genes.
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