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Leung HT, Kwok SY, Kwong KY, Shih FY, Tsao S, Chung BHY. Prioritize Variant Reclassification in Pediatric Long QT Syndrome-Time to Revisit. Pediatr Cardiol 2024; 45:1023-1035. [PMID: 38565666 DOI: 10.1007/s00246-024-03461-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 02/26/2024] [Indexed: 04/04/2024]
Abstract
Congenital long QT syndrome (LQTS) is an inherited arrhythmia syndrome associated with sudden cardiac death. Accurate interpretation and classification of genetic variants in LQTS patients are crucial for effective management. All patients with LQTS with a positive genetic test over the past 18 years (2002-2020) in our single tertiary pediatric cardiac center were identified. Reevaluation of the reported variants in LQTS genes was conducted using the American College of Genetics and Genomics (ACMG) guideline after refinement by the US ClinGen SVI working group and guideline by Walsh et al. on genetic variant reclassification, under multidisciplinary input. Among the 59 variants identified. 18 variants (30.5%) were reclassified. A significant larger portion of variants of unknown significance (VUS) were reclassified compared to likely pathogenic (LP)/pathogenic (P) variants (57.7% vs 9.1%, p < 0.001). The rate of reclassification was significantly higher in the limited/disputed evidence group compared to the definite/moderate evidence group (p = 0.0006). All LP/P variants were downgraded in the limited/disputed evidence group (p = 0.0057). VUS upgrades are associated with VUS located in genes within the definite/moderate evidence group (p = 0.0403) and with VUS present in patients exhibiting higher corrected QT intervals (QTc) (p = 0.0445). A significant number of pediatric LQTS variants were reclassified, particularly for VUS. The strength of the gene-disease association of the genes influences the reclassification performance. The study provides important insights and guidance for pediatricians to seek for reclassification of "outdated variants" in order to facilitate contemporary precision medicine.
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Affiliation(s)
- Hei-To Leung
- Department of Paediatrics & Adolescent Medicine, Hong Kong Children's Hospital, 1 Shing Cheong Rd, Ngau Tau Kok, Hong Kong SAR, China
| | - Sit-Yee Kwok
- Department of Paediatrics & Adolescent Medicine, Hong Kong Children's Hospital, 1 Shing Cheong Rd, Ngau Tau Kok, Hong Kong SAR, China.
| | - Ka-Yee Kwong
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong SAR, China
| | - Fong-Ying Shih
- Clinical Genetics Service Unit, Hong Kong Children's Hospital, Kowloon Bay, Hong Kong SAR, China
| | - Sabrina Tsao
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong SAR, China
| | - Brian Hon-Yin Chung
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong SAR, China
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Bhattacharya A, Parlanti P, Cavallo L, Farrow E, Spivey T, Renieri A, Mari F, Manzini MC. A novel framework for functional annotation of variants of uncertain significance in ID/ASD risk gene CC2D1A. Hum Mol Genet 2024:ddae070. [PMID: 38652285 DOI: 10.1093/hmg/ddae070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/07/2024] [Accepted: 04/11/2024] [Indexed: 04/25/2024] Open
Abstract
Intellectual disability (ID) and autism spectrum disorder (ASD) are genetically heterogeneous with hundreds of identified risk genes, most affecting only a few patients. Novel missense variants in these genes are being discovered as clinical exome sequencing is now routinely integrated into diagnosis, yet most of them are annotated as variants of uncertain significance (VUS). VUSs are a major roadblock in using patient genetics to inform clinical action. We developed a framework to characterize VUSs in Coiled-coil and C2 domain containing 1A (CC2D1A), a gene causing autosomal recessive ID with comorbid ASD in 40% of cases. We analyzed seven VUSs (p.Pro319Leu, p.Ser327Leu, p.Gly441Val, p.Val449Met, p.Thr580Ile, p.Arg886His and p.Glu910Lys) from four cases of individuals with ID and ASD. Variants were cloned and overexpressed in HEK293 individually and in their respective heterozygous combination. CC2D1A is a signaling scaffold that positively regulates PKA-CREB signaling by repressing phosphodiesterase 4D (PDE4D) to prevent cAMP degradation. After testing multiple parameters including direct interaction between PDE4D and CC2D1A, cAMP levels and CREB activation, we found that the most sensitive readout was CREB transcriptional activity using a luciferase assay. Compared to WT CC2D1A, five VUSs (p.Pro319Leu, p.Gly441Val, p.Val449Met, p.Thr580Ile, and p.Arg886His) led to significantly blunted response to forskolin induced CREB activation. This luciferase assay approach can be scaled up to annotate ~150 CC2D1A VUSs that are currently listed in ClinVar. Since CREB activation is a common denominator for multiple ASD/ID genes, our paradigm can also be adapted for their VUSs.
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Affiliation(s)
- Aniket Bhattacharya
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Rutgers - Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - Paola Parlanti
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Rutgers - Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - Luca Cavallo
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Rutgers - Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - Edward Farrow
- Department of Pharmacology and Physiology, School of Medicine and Health Sciences, George Washington University, 2121 I St NW, Washington, DC 20052, United States
| | - Tyler Spivey
- Department of Pharmacology and Physiology, School of Medicine and Health Sciences, George Washington University, 2121 I St NW, Washington, DC 20052, United States
| | - Alessandra Renieri
- Medical Genetics, University of Siena, Viale Bracci 2, 53100 Siena, Italy
| | - Francesca Mari
- Medical Genetics, University of Siena, Viale Bracci 2, 53100 Siena, Italy
| | - M Chiara Manzini
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Rutgers - Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
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3
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Grønbæk-Thygesen M, Hartmann-Petersen R. Cellular and molecular mechanisms of aspartoacylase and its role in Canavan disease. Cell Biosci 2024; 14:45. [PMID: 38582917 PMCID: PMC10998430 DOI: 10.1186/s13578-024-01224-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 03/24/2024] [Indexed: 04/08/2024] Open
Abstract
Canavan disease is an autosomal recessive and lethal neurological disorder, characterized by the spongy degeneration of the white matter in the brain. The disease is caused by a deficiency of the cytosolic aspartoacylase (ASPA) enzyme, which catalyzes the hydrolysis of N-acetyl-aspartate (NAA), an abundant brain metabolite, into aspartate and acetate. On the physiological level, the mechanism of pathogenicity remains somewhat obscure, with multiple, not mutually exclusive, suggested hypotheses. At the molecular level, recent studies have shown that most disease linked ASPA gene variants lead to a structural destabilization and subsequent proteasomal degradation of the ASPA protein variants, and accordingly Canavan disease should in general be considered a protein misfolding disorder. Here, we comprehensively summarize the molecular and cell biology of ASPA, with a particular focus on disease-linked gene variants and the pathophysiology of Canavan disease. We highlight the importance of high-throughput technologies and computational prediction tools for making genotype-phenotype predictions as we await the results of ongoing trials with gene therapy for Canavan disease.
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Affiliation(s)
- Martin Grønbæk-Thygesen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200N, Copenhagen, Denmark.
| | - Rasmus Hartmann-Petersen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200N, Copenhagen, Denmark.
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van der Laan L, Lauffer P, Rooney K, Silva A, Haghshenas S, Relator R, Levy MA, Trajkova S, Huisman SA, Bijlsma EK, Kleefstra T, van Bon BW, Baysal Ö, Zweier C, Palomares-Bralo M, Fischer J, Szakszon K, Faivre L, Piton A, Mesman S, Hochstenbach R, Elting MW, van Hagen JM, Plomp AS, Mannens MMAM, Alders M, van Haelst MM, Ferrero GB, Brusco A, Henneman P, Sweetser DA, Sadikovic B, Vitobello A, Menke LA. DNA methylation episignature and comparative epigenomic profiling for Pitt-Hopkins syndrome caused by TCF4 variants. HGG Adv 2024:100289. [PMID: 38571311 DOI: 10.1016/j.xhgg.2024.100289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 03/26/2024] [Accepted: 03/26/2024] [Indexed: 04/05/2024] Open
Abstract
BACKGROUND Pitt-Hopkins syndrome (PTHS) is a neurodevelopmental disorder caused by pathogenic variants in TCF4, leading to intellectual disability, specific morphological features, and autonomic nervous system dysfunction. Epigenetic dysregulation has been implicated in PTHS, prompting the investigation of a DNA methylation (DNAm) "episignature" specific to PTHS, for diagnostic purposes and variant reclassification, and further functional insights into the molecular pathophysiology of this disorder. METHODS A cohort of 67 individuals with genetically confirmed PTHS and three individuals with intellectual disability and a variant of uncertain significance (VUS) in TCF4 were studied. The DNAm episignature was developed with an Infinium Methylation EPIC BeadChip array analysis, using peripheral blood cells. Support vector machine (SVM) modeling and clustering methods were employed to generate a DNAm classifier for PTHS. Validation was extended to an additional cohort of 11 individuals with PTHS. The episignature was further assessed in relation to other neurodevelopmental disorders and its specificity was examined. RESULTS A specific DNAm episignature for PTHS was established. The classifier exhibited high sensitivity for TCF4 haploinsufficiency and missense variants in the basic helix-loop-helix domain. Notably, seven individuals with TCF4 variants exhibited negative episignatures, suggesting complexities related to mosaicism, genetic factors, and environmental influences. The episignature displayed degrees of overlap with other related disorders and biological pathways. CONCLUSIONS This study defines a DNAm episignature for TCF4-related PTHS, enabling improved diagnostic accuracy and VUS reclassification. The finding that some cases scored negative underscores the potential for multiple or nested episignatures and emphasizes the need for continued investigation to enhance specificity and coverage across PTHS-related variants.
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Affiliation(s)
- Liselot van der Laan
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - Peter Lauffer
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - Kathleen Rooney
- Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Ananília Silva
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Sadegheh Haghshenas
- Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON, Canada
| | - Raissa Relator
- Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON, Canada
| | - Michael A Levy
- Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON, Canada
| | - Slavica Trajkova
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Sylvia A Huisman
- Amsterdam UMC location University of Amsterdam, Emma Children's hospital, Department of Pediatrics, Amsterdam, The Netherlands; Zodiak, Prinsenstichting, Purmerend, The Netherlands
| | - Emilia K Bijlsma
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Tjitske Kleefstra
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Bregje W van Bon
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Özlem Baysal
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Christiane Zweier
- Department of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Department of Human Genetics, University of Bern, Inselspital Universitätsspital Bern, Bern, Switzerland
| | - María Palomares-Bralo
- Institute of Medical and Molecular Genetics (INGEMM), La Paz University Hospital, Madrid, Spain
| | - Jan Fischer
- Institute for Clinical Genetics, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany
| | - Katalin Szakszon
- Institute of Paediatrics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Laurence Faivre
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHUTRANSLAD, Dijon, France; CHU Dijon Bourgogne, Centre de Génétique, Centre de Référence Maladies Rares «Anomalies du Développement et Syndromes Malformatifs», FHU-TRANSLDAD, Dijon, France
| | - Amélie Piton
- Genetic diagnosis laboratories, Strasbourg Universitary Hospital, Strasbourg, 67000, France
| | - Simone Mesman
- Swammerdam Institute for Life Sciences, FNWI, University of Amsterdam, Amsterdam, The Netherlands
| | - Ron Hochstenbach
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - Mariet W Elting
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - Johanna M van Hagen
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - Astrid S Plomp
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - Marcel M A M Mannens
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - Mariëlle Alders
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - Mieke M van Haelst
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - Giovanni B Ferrero
- Department of Public Health and Pediatrics, University of Torino, Turin, Italy
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, Turin, Italy
| | - Peter Henneman
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands
| | - David A Sweetser
- Division of Medical Genetics and Metabolism and Center for Genomic Medicine, Massachusetts General for Children, Boston, Massachusetts
| | - Bekim Sadikovic
- Department of Human Genetics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands; Amsterdam Reproduction & Development, Amsterdam, The Netherlands; Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Antonio Vitobello
- Unité Fonctionnelle Innovation en Diagnostic Génomique des Maladies Rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France Amsterdam Neuroscience - Cellular & Molecular Mechanisms, Amsterdam, The Netherlands
| | - Leonie A Menke
- Amsterdam Reproduction & Development, Amsterdam, The Netherlands; Amsterdam UMC location University of Amsterdam, Emma Children's hospital, Department of Pediatrics, Amsterdam, The Netherlands.
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Sanoguera-Miralles L, Llinares-Burguet I, Bueno-Martínez E, Ramadane-Morchadi L, Stuani C, Valenzuela-Palomo A, García-Álvarez A, Pérez-Segura P, Buratti E, de la Hoya M, Velasco-Sampedro EA. Comprehensive splicing analysis of the alternatively spliced CHEK2 exons 8 and 10 reveals three enhancer/silencer-rich regions and 38 spliceogenic variants. J Pathol 2024; 262:395-409. [PMID: 38332730 DOI: 10.1002/path.6243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/26/2023] [Accepted: 11/28/2023] [Indexed: 02/10/2024]
Abstract
Splicing is controlled by a large set of regulatory elements (SREs) including splicing enhancers and silencers, which are involved in exon recognition. Variants at these motifs may dysregulate splicing and trigger loss-of-function transcripts associated with disease. Our goal here was to study the alternatively spliced exons 8 and 10 of the breast cancer susceptibility gene CHEK2. For this purpose, we used a previously published minigene with exons 6-10 that produced the expected minigene full-length transcript and replicated the naturally occurring events of exon 8 [Δ(E8)] and exon 10 [Δ(E10)] skipping. We then introduced 12 internal microdeletions of exons 8 and 10 by mutagenesis in order to map SRE-rich intervals by splicing assays in MCF-7 cells. We identified three minimal (10-, 11-, 15-nt) regions essential for exon recognition: c.863_877del [ex8, Δ(E8): 75%] and c.1073_1083del and c.1083_1092del [ex10, Δ(E10): 97% and 62%, respectively]. Then 87 variants found within these intervals were introduced into the wild-type minigene and tested functionally. Thirty-eight of them (44%) impaired splicing, four of which (c.883G>A, c.883G>T, c.884A>T, and c.1080G>T) induced negligible amounts (<5%) of the minigene full-length transcript. Another six variants (c.886G>A, c.886G>T, c.1075G>A, c.1075G>T, c.1076A>T, and c.1078G>T) showed significantly strong impacts (20-50% of the minigene full-length transcript). Thirty-three of the 38 spliceogenic variants were annotated as missense, three as nonsense, and two as synonymous, underlying the fact that any exonic change is capable of disrupting splicing. Moreover, c.883G>A, c.883G>T, and c.884A>T were classified as pathogenic/likely pathogenic variants according to ACMG/AMP (American College of Medical Genetics and Genomics/Association for Molecular Pathology)-based criteria. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
| | - Inés Llinares-Burguet
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
| | - Elena Bueno-Martínez
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
| | - Lobna Ramadane-Morchadi
- Molecular Oncology Laboratory CIBERONC, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Madrid, Spain
| | - Cristiana Stuani
- Molecular Pathology Lab. International Centre of Genetic Engineering and Biotechnology, Trieste, Italy
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
| | - Alicia García-Álvarez
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
| | - Pedro Pérez-Segura
- Molecular Oncology Laboratory CIBERONC, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Madrid, Spain
| | - Emanuele Buratti
- Molecular Pathology Lab. International Centre of Genetic Engineering and Biotechnology, Trieste, Italy
| | - Miguel de la Hoya
- Molecular Oncology Laboratory CIBERONC, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Madrid, Spain
| | - Eladio A Velasco-Sampedro
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
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Hu C, Huang H, Na J, Lumby C, Abozaid M, Holdren MA, Rao TJ, Karam R, Pesaran T, Weyandt JD, Csuy CM, Seelaus CA, Young CC, Fulk K, Heidari Z, Morais Lyra PC, Couch RE, Persons B, Polley EC, Gnanaolivu RD, Boddicker NJ, Monteiro ANA, Yadav S, Domchek SM, Richardson ME, Couch FJ. Functional analysis and clinical classification of 462 germline BRCA2 missense variants affecting the DNA binding domain. Am J Hum Genet 2024; 111:584-593. [PMID: 38417439 PMCID: PMC10940015 DOI: 10.1016/j.ajhg.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 02/01/2024] [Accepted: 02/01/2024] [Indexed: 03/01/2024] Open
Abstract
Variants of uncertain significance (VUSs) in BRCA2 are a common result of hereditary cancer genetic testing. While more than 4,000 unique VUSs, comprised of missense or intronic variants, have been identified in BRCA2, the few missense variants now classified clinically as pathogenic or likely pathogenic are predominantly located in the region encoding the C-terminal DNA binding domain (DBD). We report on functional evaluation of the influence of 462 BRCA2 missense variants affecting the DBD on DNA repair activity of BRCA2 using a homology-directed DNA double-strand break repair assay. Of these, 137 were functionally abnormal, 313 were functionally normal, and 12 demonstrated intermediate function. Comparisons with other functional studies of BRCA2 missense variants yielded strong correlations. Sequence-based in silico prediction models had high sensitivity, but limited specificity, relative to the homology-directed repair assay. Combining the functional results with clinical and genetic data in an American College of Medical Genetics (ACMG)/Association for Molecular Pathology (AMP)-like variant classification framework from a clinical testing laboratory, after excluding known splicing variants and functionally intermediate variants, classified 431 of 442 (97.5%) missense variants (129 as pathogenic/likely pathogenic and 302 as benign/likely benign). Functionally abnormal variants classified as pathogenic by ACMG/AMP rules were associated with a slightly lower risk of breast cancer (odds ratio [OR] 5.15, 95% confidence interval [CI] 3.43-7.83) than BRCA2 DBD protein truncating variants (OR 8.56, 95% CI 6.03-12.36). Overall, functional studies of BRCA2 variants using validated assays substantially improved the variant classification yield from ACMG/AMP models and are expected to improve clinical management of many individuals found to harbor germline BRCA2 missense VUS.
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Affiliation(s)
- Chunling Hu
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55902, USA
| | - Huaizhi Huang
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55902, USA
| | - Jie Na
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN 55902, USA
| | - Carolyn Lumby
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55902, USA
| | - Mohamed Abozaid
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55902, USA
| | - Megan A Holdren
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55902, USA
| | - Tara J Rao
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55902, USA
| | | | | | | | | | | | | | - Kelly Fulk
- Ambry Genetics, Aliso Viejo, CA 92656, USA
| | | | | | - Ronan E Couch
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55902, USA
| | - Benjamin Persons
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55902, USA
| | - Eric C Polley
- Department of Public Health Sciences, University of Chicago, Chicago, IL 60637, USA
| | - Rohan D Gnanaolivu
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN 55902, USA
| | - Nicholas J Boddicker
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN 55902, USA
| | | | - Siddhartha Yadav
- Department of Medical Oncology, Mayo Clinic, Rochester, MN 55902, USA
| | - Susan M Domchek
- Division of Hematology Oncology, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Fergus J Couch
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55902, USA; Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN 55902, USA.
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7
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Ostroverkhova D, Tyryshkin K, Beach AK, Moore EA, Masoudi-Sobhanzadeh Y, Barbari SR, Rogozin IB, Shaitan KV, Panchenko AR, Shcherbakova PV. DNA polymerase ε and δ variants drive mutagenesis in polypurine tracts in human tumors. Cell Rep 2024; 43:113655. [PMID: 38219146 PMCID: PMC10830898 DOI: 10.1016/j.celrep.2023.113655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 11/07/2023] [Accepted: 12/19/2023] [Indexed: 01/16/2024] Open
Abstract
Alterations in the exonuclease domain of DNA polymerase ε cause ultramutated cancers. These cancers accumulate AGA>ATA transversions; however, their genomic features beyond the trinucleotide motifs are obscure. We analyze the extended DNA context of ultramutation using whole-exome sequencing data from 524 endometrial and 395 colorectal tumors. We find that G>T transversions in POLE-mutant tumors predominantly affect sequences containing at least six consecutive purines, with a striking preference for certain positions within polypurine tracts. Using this signature, we develop a machine-learning classifier to identify tumors with hitherto unknown POLE drivers and validate two drivers, POLE-E978G and POLE-S461L, by functional assays in yeast. Unlike other pathogenic variants, the E978G substitution affects the polymerase domain of Pol ε. We further show that tumors with POLD1 drivers share the extended signature of POLE ultramutation. These findings expand the understanding of ultramutation mechanisms and highlight peculiar mutagenic properties of polypurine tracts in the human genome.
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Affiliation(s)
- Daria Ostroverkhova
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, Kingston, ON, Canada
| | - Kathrin Tyryshkin
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, Kingston, ON, Canada
| | - Annette K Beach
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Elizabeth A Moore
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Yosef Masoudi-Sobhanzadeh
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, Kingston, ON, Canada
| | - Stephanie R Barbari
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Igor B Rogozin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | | | - Anna R Panchenko
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, Kingston, ON, Canada.
| | - Polina V Shcherbakova
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA.
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8
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Cooper SE, Coelho MA, Strauss ME, Gontarczyk AM, Wu Q, Garnett MJ, Marioni JC, Bassett AR. scSNV-seq: high-throughput phenotyping of single nucleotide variants by coupled single-cell genotyping and transcriptomics. Genome Biol 2024; 25:20. [PMID: 38225637 PMCID: PMC10789043 DOI: 10.1186/s13059-024-03169-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 01/09/2024] [Indexed: 01/17/2024] Open
Abstract
CRISPR screens with single-cell transcriptomic readouts are a valuable tool to understand the effect of genetic perturbations including single nucleotide variants (SNVs) associated with diseases. Interpretation of these data is currently limited as genotypes cannot be accurately inferred from guide RNA identity alone. scSNV-seq overcomes this limitation by coupling single-cell genotyping and transcriptomics of the same cells enabling accurate and high-throughput screening of SNVs. Analysis of variants across the JAK1 gene with scSNV-seq demonstrates the importance of determining the precise genetic perturbation and accurately classifies clinically observed missense variants into three functional categories: benign, loss of function, and separation of function.
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Affiliation(s)
- Sarah E Cooper
- Cellular and Gene Editing Research, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Matthew A Coelho
- Translational Cancer Genomics, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- Open Targets, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Magdalena E Strauss
- EMBL-European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge, CB2 0RE, UK
| | - Aleksander M Gontarczyk
- Cellular and Gene Editing Research, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Qianxin Wu
- Cellular and Gene Editing Research, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Mathew J Garnett
- Translational Cancer Genomics, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - John C Marioni
- EMBL-European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
- Cellular Genetics, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge, CB2 0RE, UK
- Present Address: Genentech, South San Francisco, CA, USA
| | - Andrew R Bassett
- Cellular and Gene Editing Research, Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK.
- Open Targets, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
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9
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Tam B, Qin Z, Zhao B, Sinha S, Lei CL, Wang SM. Classification of MLH1 Missense VUS Using Protein Structure-Based Deep Learning-Ramachandran Plot-Molecular Dynamics Simulations Method. Int J Mol Sci 2024; 25:850. [PMID: 38255924 PMCID: PMC10815254 DOI: 10.3390/ijms25020850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 01/24/2024] Open
Abstract
Pathogenic variation in DNA mismatch repair (MMR) gene MLH1 is associated with Lynch syndrome (LS), an autosomal dominant hereditary cancer. Of the 3798 MLH1 germline variants collected in the ClinVar database, 38.7% (1469) were missense variants, of which 81.6% (1199) were classified as Variants of Uncertain Significance (VUS) due to the lack of functional evidence. Further determination of the impact of VUS on MLH1 function is important for the VUS carriers to take preventive action. We recently developed a protein structure-based method named "Deep Learning-Ramachandran Plot-Molecular Dynamics Simulation (DL-RP-MDS)" to evaluate the deleteriousness of MLH1 missense VUS. The method extracts protein structural information by using the Ramachandran plot-molecular dynamics simulation (RP-MDS) method, then combines the variation data with an unsupervised learning model composed of auto-encoder and neural network classifier to identify the variants causing significant change in protein structure. In this report, we applied the method to classify 447 MLH1 missense VUS. We predicted 126/447 (28.2%) MLH1 missense VUS were deleterious. Our study demonstrates that DL-RP-MDS is able to classify the missense VUS based solely on their impact on protein structure.
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Affiliation(s)
- Benjamin Tam
- Ministry of Education Frontiers Science Center for Precision Oncology, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Cancer Centre, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Zixin Qin
- Ministry of Education Frontiers Science Center for Precision Oncology, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Cancer Centre, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Bojin Zhao
- Ministry of Education Frontiers Science Center for Precision Oncology, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Cancer Centre, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Siddharth Sinha
- Ministry of Education Frontiers Science Center for Precision Oncology, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Cancer Centre, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Chon Lok Lei
- Ministry of Education Frontiers Science Center for Precision Oncology, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Cancer Centre, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - San Ming Wang
- Ministry of Education Frontiers Science Center for Precision Oncology, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Cancer Centre, Faculty of Health Sciences, University of Macau, Macau SAR, China
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau SAR, China
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10
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Rehm HL, Alaimo JT, Aradhya S, Bayrak-Toydemir P, Best H, Brandon R, Buchan JG, Chao EC, Chen E, Clifford J, Cohen ASA, Conlin LK, Das S, Davis KW, Del Gaudio D, Del Viso F, DiVincenzo C, Eisenberg M, Guidugli L, Hammer MB, Harrison SM, Hatchell KE, Dyer LH, Hoang LU, Holt JM, Jobanputra V, Karbassi ID, Kearney HM, Kelly MA, Kelly JM, Kluge ML, Komala T, Kruszka P, Lau L, Lebo MS, Marshall CR, McKnight D, McWalter K, Meng Y, Nagan N, Neckelmann CS, Neerman N, Niu Z, Paolillo VK, Paolucci SA, Perry D, Pesaran T, Radtke K, Rasmussen KJ, Retterer K, Saunders CJ, Spiteri E, Stanley C, Szuto A, Taft RJ, Thiffault I, Thomas BC, Thomas-Wilson A, Thorpe E, Tidwell TJ, Towne MC, Zouk H. The landscape of reported VUS in multi-gene panel and genomic testing: Time for a change. Genet Med 2023; 25:100947. [PMID: 37534744 PMCID: PMC10825061 DOI: 10.1016/j.gim.2023.100947] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/20/2023] [Accepted: 07/26/2023] [Indexed: 08/04/2023] Open
Abstract
PURPOSE Variants of uncertain significance (VUS) are a common result of diagnostic genetic testing and can be difficult to manage with potential misinterpretation and downstream costs, including time investment by clinicians. We investigated the rate of VUS reported on diagnostic testing via multi-gene panels (MGPs) and exome and genome sequencing (ES/GS) to measure the magnitude of uncertain results and explore ways to reduce their potentially detrimental impact. METHODS Rates of inconclusive results due to VUS were collected from over 1.5 million sequencing test results from 19 clinical laboratories in North America from 2020 to 2021. RESULTS We found a lower rate of inconclusive test results due to VUSs from ES/GS (22.5%) compared with MGPs (32.6%; P < .0001). For MGPs, the rate of inconclusive results correlated with panel size. The use of trios reduced inconclusive rates (18.9% vs 27.6%; P < .0001), whereas the use of GS compared with ES had no impact (22.2% vs 22.6%; P = ns). CONCLUSION The high rate of VUS observed in diagnostic MGP testing warrants examining current variant reporting practices. We propose several approaches to reduce reported VUS rates, while directing clinician resources toward important VUS follow-up.
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Affiliation(s)
- Heidi L Rehm
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA; Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA; Pathology, Harvard Medical School, Boston, MA.
| | - Joseph T Alaimo
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO; Department of Pediatrics, School of Medicine, University of Missouri, Kansas City, MO; Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO
| | - Swaroop Aradhya
- Invitae, San Francisco, CA; Department of Pathology, Stanford University School of Medicine, Palo Alto, CA
| | - Pinar Bayrak-Toydemir
- ARUP Laboratories, Salt Lake City, UT; Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT
| | - Hunter Best
- ARUP Laboratories, Salt Lake City, UT; Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT
| | | | - Jillian G Buchan
- Genetics Division, Laboratory Medicine and Pathology, University of Washington, Seattle, WA
| | | | | | | | - Ana S A Cohen
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO; Department of Pediatrics, School of Medicine, University of Missouri, Kansas City, MO; Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO
| | - Laura K Conlin
- Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, PA; Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA
| | - Soma Das
- Human Genetics, University of Chicago, Chicago, IL
| | | | | | - Florencia Del Viso
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO
| | | | - Marcia Eisenberg
- Women's Health and Genetics, Labcorp, Research Triangle Park, NC
| | - Lucia Guidugli
- Rady Children's Institute for Genomic Medicine, San Diego, CA
| | - Monia B Hammer
- Rady Children's Institute for Genomic Medicine, San Diego, CA
| | | | | | | | | | - James M Holt
- HudsonAlpha Clinical Services Lab, LLC, Huntsville, AL
| | - Vaidehi Jobanputra
- Molecular Diagnostics, New York Genome Center, New York, NY; Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | | | - Hutton M Kearney
- Division of Laboratory Genetics and Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
| | | | - Jacob M Kelly
- HudsonAlpha Clinical Services Lab, LLC, Huntsville, AL
| | - Michelle L Kluge
- Division of Laboratory Genetics and Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
| | | | | | - Lynette Lau
- Division of Genome Diagnostics, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Matthew S Lebo
- Pathology, Harvard Medical School, Boston, MA; Laboratory for Molecular Medicine, Mass General Brigham, Cambridge, MA
| | - Christian R Marshall
- Division of Genome Diagnostics, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | | | | | - Yan Meng
- Fulgent Genetics, Temple City, CA
| | | | | | | | - Zhiyv Niu
- Division of Laboratory Genetics and Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
| | - Vitoria K Paolillo
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO
| | - Sarah A Paolucci
- Genetics Division, Laboratory Medicine and Pathology, University of Washington, Seattle, WA
| | | | | | | | - Kristen J Rasmussen
- Division of Laboratory Genetics and Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
| | | | - Carol J Saunders
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO; Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO; Department of Pediatrics and Pathology, School of Medicine, University of Missouri, Kansas City, MO
| | | | | | - Anna Szuto
- Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, ON, Canada
| | | | - Isabelle Thiffault
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO; Department of Pediatrics, School of Medicine, University of Missouri, Kansas City, MO; Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO
| | | | | | | | | | | | - Hana Zouk
- Pathology, Harvard Medical School, Boston, MA; Laboratory for Molecular Medicine, Mass General Brigham, Cambridge, MA
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11
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Biswas K, Mitrophanov AY, Sahu S, Sullivan T, Southon E, Nousome D, Reid S, Narula S, Smolen J, Sengupta T, Riedel-Topper M, Kapoor M, Babbar A, Stauffer S, Cleveland L, Tandon M, Malys T, Sharan SK. Sequencing-based functional assays for classification of BRCA2 variants in mouse ESCs. Cell Rep Methods 2023; 3:100628. [PMID: 37922907 PMCID: PMC10694496 DOI: 10.1016/j.crmeth.2023.100628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/12/2023] [Accepted: 10/12/2023] [Indexed: 11/07/2023]
Abstract
Sequencing of genes, such as BRCA1 and BRCA2, is recommended for individuals with a personal or family history of early onset and/or bilateral breast and/or ovarian cancer or a history of male breast cancer. Such sequencing efforts have resulted in the identification of more than 17,000 BRCA2 variants. The functional significance of most variants remains unknown; consequently, they are called variants of uncertain clinical significance (VUSs). We have previously developed mouse embryonic stem cell (mESC)-based assays for functional classification of BRCA2 variants. We now developed a next-generation sequencing (NGS)-based approach for functional evaluation of BRCA2 variants using pools of mESCs expressing 10-25 BRCA2 variants from a given exon. We use this approach for functional evaluation of 223 variants listed in ClinVar. Our functional classification of BRCA2 variants is concordant with the classification reported in ClinVar or those reported by other orthogonal assays.
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Affiliation(s)
- Kajal Biswas
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Alexander Y Mitrophanov
- Statistical Consulting and Scientific Programming, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Sounak Sahu
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Teresa Sullivan
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Eileen Southon
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA; Leidos Biomed Research Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Darryl Nousome
- Biomedical Informatics and Data Science, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Susan Reid
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Sakshi Narula
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Julia Smolen
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Trisha Sengupta
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Maximilian Riedel-Topper
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Medha Kapoor
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Anav Babbar
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Stacey Stauffer
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Linda Cleveland
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Mayank Tandon
- Biomedical Informatics and Data Science, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Tyler Malys
- Statistical Consulting and Scientific Programming, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Shyam K Sharan
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
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12
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Yadegari F, Farahmand L, Esmaeili R, Zarinfam S, Majidzadeh-A K. Inter-BRCT linker is probably the most intolerant region of the BRCA1 BRCT domain. J Biomol Struct Dyn 2023:1-13. [PMID: 37948190 DOI: 10.1080/07391102.2023.2274517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 06/15/2023] [Indexed: 11/12/2023]
Abstract
Pathogenic mutations in BRCA1 are associated with an increased risk of hereditary breast, ovarian, and some other cancers; however, the clinical significance of many mutations in this gene remains unknown (Variants of Unknown Significance/VUS). Since mutations in intolerant regions of a protein lead to dysfunction and pathogenicity, identifying these regions helps to predict the clinical importance of VUSs. This study aimed to identify intolerant regions of BRCA1 and understand the possible root of this susceptibility. Intolerant regions appear to carry more pathogenic mutations than expected due to their lower tolerance to missense variations. Therefore, we hypothesized that among the BRCA1 regions, the higher the mutation density, the greater the intolerance. Thus, pathogenic mutation density and regional intolerance scores were calculated to identify BRCA1-intolerant regions. To investigate the pathogenic mechanisms of missense-intolerant regions in BRCA1, transcription activation (TA) experiments and molecular dynamics (MD) simulations were also performed. The results showed that the RING domain, followed by the BRCT domain, has the highest density of pathogenic mutations. In the BRCT domain, a higher density of pathogenic mutations was observed in the inter-BRCT linker. Additionally, scores generated by Missense Tolerance Ratio-3D (MTR3D) and the Missense Tolerance Ratio consensus (MTRX) showed that the inter-BRCT linker is more intolerant than other regions of the BRCT domain. The MD results showed that mutations in the inter-BRCT linker led to cancer susceptibility, likely due to disruption of the interaction between BRCA1 and phosphopeptides. TA laboratory assays further supported the importance of the inter-BRCT linker.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Fatemeh Yadegari
- Genetics Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran
| | - Leila Farahmand
- Recombinant Proteins Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran
| | - Rezvan Esmaeili
- Genetics Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran
| | - Shiva Zarinfam
- Genetics Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran
| | - Keivan Majidzadeh-A
- Genetics Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, Iran
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13
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Khan MA, Varma AK. In silico and structure-based assessment to classify VUS identified in the α-helical domain of BRCA2. J Biomol Struct Dyn 2023; 41:9879-9889. [PMID: 36404616 DOI: 10.1080/07391102.2022.2148127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 11/10/2022] [Indexed: 11/22/2022]
Abstract
Breast cancer type 2 susceptibility (BRCA2) protein plays a crucial role in DNA double-strand breaks repair mechanism by homologous recombination. Pathogenic mutations in the BRCA2 gene confer an increased risk of hereditary breast and ovarian cancer (HBOC). Different missense mutations are identified from a larger cohort of patient populations in the BRCA2. However, most missense mutations are classified as 'Variants of Uncertain Significance' (VUS) due to a lack of data from structural, functional, and clinical assessments. Therefore, this study focused on assessing VUS identified in the α-helical domain of h-BRCA2 using different in silico tools and structure-based molecular dynamics simulation. A total of 286 identified VUS were evaluated using Align-GVGD, PROVEAN and PANTHER servers and 18 variants were predicted to be pathogenic. Further, out of 18 variants analyzed using the ConSurf server, 16 variants were found to be evolutionary conserved. These 16 conserved variants were submitted to PremPS and Dynamut server to assess the effect of the mutation at the protein structure level; 12 mutations were predicted to have a destabilizing effect on the native protein structure. Finally, molecular dynamics simulations revealed 5 variants BRCA2 Cys2646Tyr, Asp2665Val, Trp2619Arg, Trp2619Ser and Tyr2660Cys can alter the folding pattern and need further validation using in vitro, structural and in vivo studies to classify as pathogenic.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Mudassar Ali Khan
- Tata Memorial Centre, Advanced Centre for Treatment, Research and Education in Cancer, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Mumbai, Maharashtra, India
| | - Ashok K Varma
- Tata Memorial Centre, Advanced Centre for Treatment, Research and Education in Cancer, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Mumbai, Maharashtra, India
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14
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Hollstein R, Peron A, Wendt KS, Parenti I. Editorial: Pathogenic mechanisms in neurodevelopmental disorders: advances in cellular models and multi-omics approaches. Front Cell Dev Biol 2023; 11:1296885. [PMID: 37868909 PMCID: PMC10588624 DOI: 10.3389/fcell.2023.1296885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 09/27/2023] [Indexed: 10/24/2023] Open
Affiliation(s)
- R. Hollstein
- Institute of Human Genetics, University of Bonn and University Hospital Bonn, Bonn, Germany
| | - A. Peron
- Medical Genetics, Meyer Children’s Hospital IRCCS, Florence, Italy
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, Università Degli Studi Di Firenze, Florence, Italy
| | - K. S. Wendt
- Department of Cell Biology, Erasmus MC, Rotterdam, Netherlands
| | - I. Parenti
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, Essen, Germany
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15
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Arslan A. Pathogenic variants of human GABRA1 gene associated with epilepsy: A computational approach. Heliyon 2023; 9:e20218. [PMID: 37809401 PMCID: PMC10559982 DOI: 10.1016/j.heliyon.2023.e20218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/17/2023] [Accepted: 09/13/2023] [Indexed: 10/10/2023] Open
Abstract
Critical for brain development, neurodevelopmental and network disorders, the GABRA1 gene encodes for the α1 subunit, an abundantly and developmentally expressed subunit of heteropentameric gamma-aminobutyric acid A receptors (GABAARs) mediating primary inhibition in the brain. Mutations of the GABAAR subunit genes including GABRA1 gene are associated with epilepsy, a group of syndromes, characterized by unprovoked seizures and diagnosed by integrative approach, that involves genetic testing. Despite the diagnostic use of genetic testing, a large fraction of the GABAAR subunit gene variants including the variants of GABRA1 gene is not known in terms of their molecular consequence, a challenge for precision and personalized medicine. Addressing this, one hundred thirty-seven GABRA1 gene variants of unknown clinical significance have been extracted from the ClinVar database and computationally analyzed for pathogenicity. Eight variants (L49H, P59L, W97R, D99G, G152S, V270G, T294R, P305L) are predicted as pathogenic and mapped to the α1 subunit's extracellular domain (ECD), transmembrane domains (TMDs) and extracellular linker. This is followed by the integration with relevant data for cellular pathology and severity of the epilepsy syndromes retrieved from the literature. Our results suggest that the pathogenic variants in the ECD of GABRA1 (L49H, P59L, W97R, D99G, G152S) will probably manifest decreased surface expression and reduced current with mild epilepsy phenotypes while V270G, T294R in the TMDs and P305L in the linker between the second and the third TMDs will likely cause reduced cell current with severe epilepsy phenotypes. The results presented in this study provides insights for clinical genetics and wet lab experimentation.
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Affiliation(s)
- Ayla Arslan
- Department of Molecular Biology and Genetics, Faculty of Engineering and Natural Sciences, Üsküdar University, Istanbul, Turkey
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16
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Cristofoli F, Daja M, Maltese PE, Guerri G, Tanzi B, Miotto R, Bonetti G, Miertus J, Chiurazzi P, Stuppia L, Gatta V, Cecchin S, Bertelli M, Marceddu G. MAGI-ACMG: Algorithm for the Classification of Variants According to ACMG and ACGS Recommendations. Genes (Basel) 2023; 14:1600. [PMID: 37628650 PMCID: PMC10454715 DOI: 10.3390/genes14081600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/02/2023] [Accepted: 08/05/2023] [Indexed: 08/27/2023] Open
Abstract
We have developed MAGI-ACMG, a classification algorithm that allows the classification of sequencing variants (single nucleotide or small indels) according to the recommendations of the American College of Medical Genetics (ACMG) and the Association for Clinical Genomic Science (ACGS). The MAGI-ACMG classification algorithm uses information retrieved through the VarSome Application Programming Interface (API), integrates the AutoPVS1 tool in order to evaluate more precisely the attribution of the PVS1 criterion, and performs the customized assignment of specific criteria. In addition, we propose a sub-classification scheme for variants of uncertain significance (VUS) according to their proximity either towards the "likely pathogenic" or "likely benign" classes. We also conceived a pathogenicity potential criterion (P_POT) as a proxy for segregation criteria that might be added to a VUS after posterior testing, thus allowing it to upgrade its clinical significance in a diagnostic reporting setting. Finally, we have developed a user-friendly web application based on the MAGI-ACMG algorithm, available to geneticists for variant interpretation.
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Affiliation(s)
| | | | | | | | | | | | | | - Jan Miertus
- MAGI EUREGIO, 39100 Bolzano, Italy (M.B.); (G.M.)
- MAGI’S LAB, 38068 Rovereto, Italy (S.C.)
| | - Pietro Chiurazzi
- Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- UOC Genetica Medica, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Liborio Stuppia
- Department of Psychological Health and Territorial Sciences, School of Medicine and Health Sciences, “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy; (L.S.); (V.G.)
- Unit of Molecular Genetics, Center for Advanced Studies and Technology (CAST), “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
| | - Valentina Gatta
- Department of Psychological Health and Territorial Sciences, School of Medicine and Health Sciences, “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy; (L.S.); (V.G.)
- Unit of Molecular Genetics, Center for Advanced Studies and Technology (CAST), “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
| | | | - Matteo Bertelli
- MAGI EUREGIO, 39100 Bolzano, Italy (M.B.); (G.M.)
- MAGI’S LAB, 38068 Rovereto, Italy (S.C.)
- MAGISNAT, Atlanta Tech Park, 107 Technology Parkway, Peachtree Corners, GA 30092, USA
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17
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Shi S, Qin G. Direct estimation of volume under the ROC surface with verification bias. J Biopharm Stat 2023:1-29. [PMID: 37470408 DOI: 10.1080/10543406.2023.2236202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 07/01/2023] [Indexed: 07/21/2023]
Abstract
In practice, the receiver operating characteristic (ROC) curve of a diagnostic test is widely used to show the performance of the test for discriminating two-class events. The area under the ROC curve (AUC) is proposed as an index for the assessment of the diagnostic accuracy of the test under consideration. Due to ethical and cost considerations associated with application of gold standard (GS) tests, only a subset of the patients initially tested have verified disease status. Statistical evaluation of the test performance based only on test results from subjects with verified disease status are typically biased. Various AUC estimation methods for tests with verification biased data have been developed over the last few decades. In this article, we develop new direct estimation methods for the volume under the ROC surface (VUS) by extending the AUC estimation methods for two-class diagnostic tests to three-class diagnostic tests in the presence of verification bias. The proposed methods will provide a comprehensive guide to deal with the verification bias in three-class diagnostic test accuracy studies and lead to a better choice of diagnostic tests.
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Affiliation(s)
- Shuangfei Shi
- Department of Mathematics and Statistics, Georgia State University, Atlanta, USA
| | - Gengsheng Qin
- Department of Mathematics and Statistics, Georgia State University, Atlanta, USA
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18
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Carafone L, Victor A, Harbuz-Miller I. A SDHB Variant of Unknown Significance in a Patient With a Cardiac Functional Paraganglioma. JCEM Case Rep 2023; 1:luad093. [PMID: 37908983 PMCID: PMC10580458 DOI: 10.1210/jcemcr/luad093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Indexed: 11/02/2023]
Abstract
Cardiac paragangliomas are extremely rare tumors derived from chromaffin cells of the neural crest. Succinate dehydrogenase B (SDHB) mutations are associated with metastatic potential and potentially worse prognosis. Here we describe the case of a 64-year-old man who presented with chest pain, fatigue, and weight loss. Cardiac workup revealed a nearly 7-cm cardiac mass in the right lateral wall. Incisional biopsy demonstrated paraganglioma. Plasma free normetanephrine and chromogranin A were elevated. A DOTATATE positron emission tomography/computed tomography (PET/CT) revealed avidity of the mass with no evidence of distant metastases. Next-generation sequencing of the specimen demonstrated a variant of unknown significance of SDHB at H244D. Germline testing was negative. Surgical resection was aborted due to involvement of critical structures of the heart. Systemic treatment with the multi-tyrosine kinase inhibitor cabozantinib was initiated with subsequent improvements in biochemical markers as well as reductions in maximum standardized uptake value (SUVmax) on Ga-68 DOTATATE PET/CT. After 5 months of cabozantinib, he was unable to tolerate the side effects and external beam radiation therapy was completed. In this case, we report a novel somatic SDHB mutation at H244D in a sympathetic paraganglioma presenting as a cardiac mass.
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Affiliation(s)
- Lindsay Carafone
- Division of Endocrinology, University of Rochester, Rochester, NY 14642, USA
| | - Adrienne Victor
- Division of Hematology and Oncology, University of Rochester, Rochester, NY 14642, USA
| | - Inga Harbuz-Miller
- Division of Endocrinology, University of Rochester, Rochester, NY 14642, USA
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19
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Gunawardena K, Sirisena ND, Anandagoda G, Neththikumara N, Dissanayake VHW. Germline variants of uncertain significance, their frequency, and clinico-pathological features in a cohort of Sri Lankan patients with hereditary breast cancer. BMC Res Notes 2023; 16:95. [PMID: 37277882 DOI: 10.1186/s13104-023-06365-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 05/22/2023] [Indexed: 06/07/2023] Open
Abstract
BACKGROUND Next-Generation Sequencing (NGS)-based testing in cancer patients has led to increased detection of variants of uncertain significance (VUS). VUS are genetic variants whose impact on protein function is unknown. VUS pose a challenge to clinicians and patients due to uncertainty regarding their cancer predisposition risk. Paucity of data exists on the pattern of VUS in under-represented populations. This study describes the frequency of germline VUS and clinico-pathological features in Sri Lankan hereditary breast cancer patients. METHODS Data of 72 hereditary breast cancer patients who underwent NGS-based testing between January 2015 and December 2021 were maintained prospectively in a database and analyzed retrospectively. Data were subjected to bioinformatics analysis and variants were classified according to international guidelines. RESULTS Germline variants were detected in 33/72(45.8%) patients, comprising 16(48.5%) pathogenic/likely pathogenic variants and 17(51.5%) VUS. Distribution of VUS in breast cancer predisposing genes were :APC:1(5.8%), ATM:2(11.7%), BRCA1:1(5.8%), BRCA2:5(29.4%), BRIP1:1(5.8%), CDKN2A:1(5.8%), CHEK2:2(11.7%), FANC1:1(5.8%), MET:1(5.8%), STK11:1(5.8%), NF2:1(5.8%). Mean age at cancer diagnosis in patients with VUS was 51.2 years. Most common tumour histopathology was ductal carcinoma 11(78.6%). 50% of tumours in patients having VUS in BRCA1/2 genes were hormone receptor negative. 73.3% patients had family history of breast cancer. CONCLUSIONS A significant portion of patients had a germline VUS. Highest frequency was in BRCA2 gene. Majority had family history of breast cancer. This highlights the need to undertake functional genomic studies to determine the biological effects of VUS and identify potentially clinically actionable variants that would be useful for decision-making and patient management.
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Affiliation(s)
- Kawmadi Gunawardena
- Department of Anatomy, Genetics and Biomedical Informatics, Faculty of Medicine, University of Colombo, Colombo 8, Sri Lanka
| | - Nirmala D Sirisena
- Department of Anatomy, Genetics and Biomedical Informatics, Faculty of Medicine, University of Colombo, Colombo 8, Sri Lanka.
| | - Gayani Anandagoda
- Department of Anatomy, Genetics and Biomedical Informatics, Faculty of Medicine, University of Colombo, Colombo 8, Sri Lanka
| | - Nilaksha Neththikumara
- Department of Anatomy, Genetics and Biomedical Informatics, Faculty of Medicine, University of Colombo, Colombo 8, Sri Lanka
| | - Vajira H W Dissanayake
- Department of Anatomy, Genetics and Biomedical Informatics, Faculty of Medicine, University of Colombo, Colombo 8, Sri Lanka
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20
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Diderich KEM, Klapwijk JE, van der Schoot V, Brüggenwirth HT, Joosten M, Srebniak MI. Challenges and Pragmatic Solutions in Pre-Test and Post-Test Genetic Counseling for Prenatal Exome Sequencing. Appl Clin Genet 2023; 16:89-97. [PMID: 37216148 PMCID: PMC10198275 DOI: 10.2147/tacg.s411185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 04/19/2023] [Indexed: 05/24/2023] Open
Abstract
The yield of genetic prenatal diagnosis has been notably improved by introducing whole genome chromosomal microarray (CMA) and prenatal exome sequencing (pES). However, together with increased numbers of diagnoses made, the need to manage challenging findings such as variants of unknown significance (VUS) and incidental findings (IF) also increased. We have summarized the current guidelines and recommendations and we have shown current solutions used in our tertiary center in the Netherlands. We discuss four of the most common clinical situations: fetus with normal pES results, fetus with a pathogenic finding explaining the fetal phenotype, fetus with a variant of uncertain clinical significance fitting the phenotype and fetus with a variant leading to an incidental diagnosis. Additionally, we reflect on solutions in order to facilitate genetic counseling in an NGS-era.
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Affiliation(s)
| | | | | | | | - Marieke Joosten
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands
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21
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Stalke A, Behrendt A, Hennig F, Gohlke H, Buhl N, Reinkens T, Baumann U, Schlegelberger B, Illig T, Pfister ED, Skawran B. Functional characterization of novel or yet uncharacterized ATP7B missense variants detected in patients with clinical Wilson's disease. Clin Genet 2023. [PMID: 37157876 DOI: 10.1111/cge.14352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 04/14/2023] [Accepted: 04/20/2023] [Indexed: 05/10/2023]
Abstract
Wilson's disease (WD, MIM#277900) is an autosomal recessive disorder resulting in copper excess caused by biallelic variants in the ATP7B gene (MIM#606882) encoding a copper transporting P-type ATPase. ATP7B variants of unknown significance (VUS) are detected frequently, sometimes impeding a clear diagnosis. Functional analyses can help to classify these variants as benign or pathogenic. Additionally, variants already classified as (likely) pathogenic benefit from functional analyses to understand their pathomechanism, thus contribute to the development of personalized treatment approaches in the future. We described clinical features of six WD patients and functionally characterized five ATP7B missense variants (two VUS, three yet uncharacterized likely pathogenic variants), detected in these patients. We determined the protein level, copper export capacity, and cellular localization in an in vitro model and potential structural consequences using an ATP7B protein model based on AlphaFold. Our analyses give insight into the pathomechanism and allowed reclassification for the two VUS to likely pathogenic and for two of the three likely pathogenic variants to pathogenic.
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Affiliation(s)
- Amelie Stalke
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
- Department of Pediatric Gastroenterology and Hepatology, Division of Kidney, Liver, and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Annika Behrendt
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Finja Hennig
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Nicole Buhl
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
- Department of Pediatric Gastroenterology and Hepatology, Division of Kidney, Liver, and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Thea Reinkens
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Ulrich Baumann
- Department of Pediatric Gastroenterology and Hepatology, Division of Kidney, Liver, and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | | | - Thomas Illig
- Hannover Unified Bank, Hannover Medical School, Hannover, Germany
| | - Eva-Doreen Pfister
- Department of Pediatric Gastroenterology and Hepatology, Division of Kidney, Liver, and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Britta Skawran
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
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22
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Cevik S, Biswas SB, Biswas-Fiss EE. Structural and Pathogenic Impacts of ABCA4 Variants in Retinal Degenerations-An In-Silico Study. Int J Mol Sci 2023; 24:ijms24087280. [PMID: 37108442 PMCID: PMC10138569 DOI: 10.3390/ijms24087280] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
The retina-specific ATP-binding cassette transporter protein ABCA4 is responsible for properly continuing the visual cycle by removing toxic retinoid byproducts of phototransduction. Functional impairment caused by ABCA4 sequence variations is the leading cause of autosomal recessive inherited retinal disorders, including Stargardt disease, retinitis pigmentosa, and cone-rod dystrophy. To date, more than 3000 ABCA4 genetic variants have been identified, approximately 40 percent of which have not been able to be classified for pathogenicity assessments. This study examined 30 missense ABCA4 variants using AlphaFold2 protein modeling and computational structure analysis for pathogenicity prediction. All variants classified as pathogenic (n = 10) were found to have deleterious structural consequences. Eight of the ten benign variants were structurally neutral, while the remaining two resulted in mild structural changes. This study's results provided multiple lines of computational pathogenicity evidence for eight ABCA4 variants of uncertain clinical significance. Overall, in silico analyses of ABCA4 can provide a valuable tool for understanding the molecular mechanisms of retinal degeneration and their pathogenic impact.
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Affiliation(s)
- Senem Cevik
- Department of Medical and Molecular Sciences, College of Health Sciences, University of Delaware, 16 West Main Street, Suite 302 WHL, Newark, DE 19716, USA
- Ammon Pinizzotto Biopharmaceutical Innovation Center, 590 Avenue 1743, Newark, DE 19713, USA
| | - Subhasis B Biswas
- Department of Medical and Molecular Sciences, College of Health Sciences, University of Delaware, 16 West Main Street, Suite 302 WHL, Newark, DE 19716, USA
- Ammon Pinizzotto Biopharmaceutical Innovation Center, 590 Avenue 1743, Newark, DE 19713, USA
| | - Esther E Biswas-Fiss
- Department of Medical and Molecular Sciences, College of Health Sciences, University of Delaware, 16 West Main Street, Suite 302 WHL, Newark, DE 19716, USA
- Ammon Pinizzotto Biopharmaceutical Innovation Center, 590 Avenue 1743, Newark, DE 19713, USA
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23
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Bains S, Neves R, Bos JM, Giudicessi JR, MacIntyre C, Ackerman MJ. Phenotypes of Overdiagnosed Long QT Syndrome. J Am Coll Cardiol 2023; 81:477-86. [PMID: 36725176 DOI: 10.1016/j.jacc.2022.11.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/18/2022] [Accepted: 11/03/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND Long QT syndrome (LQTS) predisposes individuals to arrhythmic syncope or seizure, sudden cardiac arrest, or sudden cardiac death (SCD). Increased physician and public awareness of LQTS-associated warning signs and an increase in electrocardiographic screening programs may contribute to overdiagnosis of LQTS. OBJECTIVES This study sought to identify the diagnostic miscues underlying the continued overdiagnosis of LQTS. METHODS Electronic medical records were reviewed for patients who arrived with an outside diagnosis of LQTS but were dismissed as having normal findings subsequently. Data were abstracted for details on referral, clinical history, and both cardiologic and genetic test results. RESULTS Overall, 290 of 1,841 (16%) patients with original diagnosis of LQTS (174 [60%] female; mean age at first Mayo Clinic evaluation, 22 ± 14 years; mean QTc interval, 427 ± 25 milliseconds) were dismissed as having normal findings. The main cause of LQTS misdiagnosis or overdiagnosis was a prolonged QTc interval secondary to vasovagal syncope (n = 87; 30%), followed by a seemingly positive genetic test result for a variant in 1 of the main LQTS genes (n = 68; 23%) that was ultimately deemed not to be of clinical significance. Furthermore, patients received misdiagnoses because of a positive family history of SCD that was deemed unrelated to LQTS (n = 46; 16%), isolated/transient QT prolongation (n = 44; 15%), or misinterpretation of the QTc interval as a result of inclusion of the U-wave (n = 40, 14%). CONCLUSIONS Knowing the 5 main determinants of discordance between a previously rendered diagnosis of LQTS and full diagnostic reversal or removal (vasovagal syncope, "pseudo"-positive genetic test result in LQTS-causative genes, family history of SCD, transient QT prolongation, and misinterpretation of the QTc interval) increases awareness and provides critical guidance to reduce this burden of overdiagnosed LQTS.
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24
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Hovland HN, Mchaina EK, Høberg-Vetti H, Ariansen SL, Sjursen W, Van Ghelue M, Haukanes BI, Knappskog PM, Aukrust I, Ognedal E. Functional Analyses of Rare Germline Missense BRCA1 Variants Located within and outside Protein Domains with Known Functions. Genes (Basel) 2023; 14. [PMID: 36833189 DOI: 10.3390/genes14020262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/20/2023] Open
Abstract
The BRCA1 protein is implicated in numerous important cellular processes to prevent genomic instability and tumorigenesis, and pathogenic germline variants predispose carriers to hereditary breast and ovarian cancer (HBOC). Most functional studies of missense variants in BRCA1 focus on variants located within the Really Interesting New Gene (RING), coiled-coil and BRCA1 C-terminal (BRCT) domains, and several missense variants in these regions have been shown to be pathogenic. However, the majority of these studies focus on domain specific assays, and have been performed using isolated protein domains and not the full-length BRCA1 protein. Furthermore, it has been suggested that BRCA1 missense variants located outside domains with known function are of no functional importance, and could be classified as (likely) benign. However, very little is known about the role of the regions outside the well-established domains of BRCA1, and only a few functional studies of missense variants located within these regions have been published. In this study, we have, therefore, functionally evaluated the effect of 14 rare BRCA1 missense variants considered to be of uncertain clinical significance, of which 13 are located outside the well-established domains and one within the RING domain. In order to investigate the hypothesis stating that most BRCA1 variants located outside the known protein domains are benign and of no functional importance, multiple protein assays including protein expression and stability, subcellular localisation and protein interactions have been performed, utilising the full-length protein to better mimic the native state of the protein. Two variants located outside the known domains (p.Met297Val and p.Asp1152Asn) and one variant within the RING domain (p.Leu52Phe) were found to make the BRCA1 protein more prone to proteasome-mediated degradation. In addition, two variants (p.Leu1439Phe and p.Gly890Arg) also located outside known domains were found to have reduced protein stability compared to the wild type protein. These findings indicate that variants located outside the RING, BRCT and coiled-coiled domains could also affect the BRCA1 protein function. For the nine remaining variants, no significant effects on BRCA1 protein functions were observed. Based on this, a reclassification of seven variants from VUS to likely benign could be suggested.
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25
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Adam F, Fluri M, Scherz A, Rabaglio M. Occurrence of variants of unknown clinical significance in genetic testing for hereditary breast and ovarian cancer syndrome and Lynch syndrome: a literature review and analytical observational retrospective cohort study. BMC Med Genomics 2023; 16:7. [PMID: 36647026 DOI: 10.1186/s12920-023-01437-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 01/09/2023] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND AND PURPOSE Over the last decade, the implementation of multigene panels for hereditary tumor syndrome has increased at our institution (Inselspital, University Hospital Berne, Switzerland). The aim of this study was to determine the prevalence of variants of unknown significance (VUS) in patients with suspected Lynch syndrome and suspected hereditary breast and ovarian cancer syndrome, the latter in connection with the trend toward ordering larger gene panels. RESULTS Retrospectively collected data from 1057 patients at our institution showed at least one VUS in 126 different cases (11.9%). In patients undergoing genetic testing for BRCA1/2, the prevalence of VUS was 6%. When < 10 additional genes were tested in addition to BRCA1/2, the prevalence increased to 13.8%, and 31.8% for > 10 additional genes, respectively. The gene most frequently affected with a VUS was ATM. 6% of our patients who were tested for Lynch syndrome had a VUS result in either MLH1, MSH2 or MSH6. CONCLUSIONS Our data demonstrate that panel testing statistically significantly increases VUS rates due to variants in non-BRCA genes. Good genetic counseling before and after obtaining results is therefore particularly important when conducting multigene panels to minimize patient uncertainty due to VUS results.
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26
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Caleca L, Radice P. Refinement of the assignment to the ACMG/AMP BS3 and PS3 criteria of eight BRCA1 variants of uncertain significance by integrating available functional data with protein interaction assays. Front Oncol 2023; 13:1146604. [PMID: 37168384 PMCID: PMC10164951 DOI: 10.3389/fonc.2023.1146604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 04/06/2023] [Indexed: 05/13/2023] Open
Abstract
The clinical screening of cancer predisposition genes has led to the identification of a large number of variants of uncertain significance (VUS). Multifactorial likelihood models that predict the odds ratio for VUS in favor or against cancer causality, have been developed, but their use is limited by the amount of necessary data, which are difficult to obtain for rare variants. The guidelines for variant interpretation of the American College of Medical Genetics and Genomics along with the Association for Molecular Pathology (ACMG/AMP) state that "well-established" functional studies provide strong support of a pathogenic or benign impact (criteria PS3 and BS3, respectively) and can be used as evidence type to reach a final classification. Moreover, the Clinical Genome Resource Sequence Variant Interpretation Working Group developed rule specifications to refine the PS3/BS3 criteria. Recently, Lira PC et al. developed the "Hi Set" approach that generated PS3/BS3 codes for over two-thousands BRCA1 VUS. While highly successful, this approach did not discriminate a group of variants with conflicting evidences. Here, we aimed to implement the outcomes of the "Hi-set" approach applying Green Fluorescent Protein (GFP)-reassembly assays, assessing the effect of variants in the RING and BRCT domains of BRCA1 on the binding of these domains with the UbcH5a or ABRAXAS proteins, respectively. The analyses of 26 clinically classified variants, including 13 tested in our previous study, showed 100% sensitivity and specificity in identifying pathogenic and benign variants for both the RING/UbcH5a and the BRCTs/ABRAXAS interactions. We derived the strength of evidences generated by the GFP-reassembly assays corresponding to moderate for both PS3 and BS3 criteria assessment. The GFP-reassembly assays were applied to the functional characterization of 8 discordant variants from the study by Lyra et al. The outcomes of these analyses, combined with those reported in the "Hi Set" study, allowed the assignment of ACMG/AMP criteria in favor or against pathogenicity for all 8 examined variants. The above findings were validated with a semi-quantitative Mammalian Two-Hybrid approach, and totally concordant results were observed. Our data contributes in shedding light on the functional significance of BRCA1 VUS and on their clinical interpretation within the ACMG/AMP framework.
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Bueno‐Martínez E, Sanoguera‐Miralles L, Valenzuela‐Palomo A, Esteban‐Sánchez A, Lorca V, Llinares‐Burguet I, Allen J, García‐Álvarez A, Pérez‐Segura P, Durán M, Easton DF, Devilee P, Vreeswijk MPG, de la Hoya M, Velasco‐Sampedro EA. Minigene-based splicing analysis and ACMG/AMP-based tentative classification of 56 ATM variants. J Pathol 2022; 258:83-101. [PMID: 35716007 PMCID: PMC9541484 DOI: 10.1002/path.5979] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/11/2022] [Accepted: 06/08/2022] [Indexed: 12/29/2022]
Abstract
The ataxia telangiectasia-mutated (ATM) protein is a major coordinator of the DNA damage response pathway. ATM loss-of-function variants are associated with 2-fold increased breast cancer risk. We aimed at identifying and classifying spliceogenic ATM variants detected in subjects of the large-scale sequencing project BRIDGES. A total of 381 variants at the intron-exon boundaries were identified, 128 of which were predicted to be spliceogenic. After further filtering, we ended up selecting 56 variants for splicing analysis. Four functional minigenes (mgATM) spanning exons 4-9, 11-17, 25-29, and 49-52 were constructed in the splicing plasmid pSAD. Selected variants were genetically engineered into the four constructs and assayed in MCF-7/HeLa cells. Forty-eight variants (85.7%) impaired splicing, 32 of which did not show any trace of the full-length (FL) transcript. A total of 43 transcripts were identified where the most prevalent event was exon/multi-exon skipping. Twenty-seven transcripts were predicted to truncate the ATM protein. A tentative ACMG/AMP (American College of Medical Genetics and Genomics/Association for Molecular Pathology)-based classification scheme that integrates mgATM data allowed us to classify 29 ATM variants as pathogenic/likely pathogenic and seven variants as likely benign. Interestingly, the likely pathogenic variant c.1898+2T>G generated 13% of the minigene FL-transcript due to the use of a noncanonical GG-5'-splice-site (0.014% of human donor sites). Circumstantial evidence in three ATM variants (leakiness uncovered by our mgATM analysis together with clinical data) provides some support for a dosage-sensitive expression model in which variants producing ≥30% of FL-transcripts would be predicted benign, while variants producing ≤13% of FL-transcripts might be pathogenic. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Elena Bueno‐Martínez
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
| | - Lara Sanoguera‐Miralles
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
| | - Alberto Valenzuela‐Palomo
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
| | - Ada Esteban‐Sánchez
- Molecular Oncology Laboratory CIBERONC, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos)MadridSpain
| | - Víctor Lorca
- Molecular Oncology Laboratory CIBERONC, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos)MadridSpain
| | - Inés Llinares‐Burguet
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
| | - Jamie Allen
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary CareUniversity of CambridgeCambridgeUK
| | - Alicia García‐Álvarez
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
| | - Pedro Pérez‐Segura
- Molecular Oncology Laboratory CIBERONC, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos)MadridSpain
| | - Mercedes Durán
- Cancer Genetics, Instituto de Biología y Genética MolecularValladolidSpain
| | - Douglas F Easton
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary CareUniversity of CambridgeCambridgeUK
| | - Peter Devilee
- Department of Human GeneticsLeiden University Medical CenterLeidenThe Netherlands
| | - Maaike PG Vreeswijk
- Department of Human GeneticsLeiden University Medical CenterLeidenThe Netherlands
| | - Miguel de la Hoya
- Molecular Oncology Laboratory CIBERONC, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos)MadridSpain
| | - Eladio A Velasco‐Sampedro
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
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Petrackova A, Savara J, Turcsanyi P, Gajdos P, Papajik T, Kriegova E. Rare germline ATM variants of uncertain significance in chronic lymphocytic leukaemia and other cancers. Br J Haematol 2022; 199:371-381. [PMID: 36029002 DOI: 10.1111/bjh.18419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 08/05/2022] [Accepted: 08/09/2022] [Indexed: 12/26/2022]
Abstract
Germline pathogenic ATM (ataxia-telangiectasia mutated) variants are associated with the risk of multiple cancers; however, genetic testing reveals a large number of ATM variants of uncertain significance (VUS). Here, we studied germline ATM variants occurring in a real-world cohort of 336 patients with chronic lymphocytic leukaemia (CLL) and public cancer whole-exome/genome-sequencing datasets (445 CLL, 75 mantle cell lymphoma, 216 metastatic breast cancer, 140 lung cancer patients). We found that two-thirds of rare germline ATM variants are pathogenic (18%-50%) or VUS-predicted pathogenic (50%-82%), depending on cancer type and reaching a prevalence of up to 8%, and one-third are VUS-predicted benign. Patients with both pathogenic and VUS-predicted pathogenic variants, all heterozygous, mostly missense, are more predisposed to biallelic ATM inactivation by acquiring deletion (del)11q than patients without these variants, similar to patients with somatic ATM variants. A functional assay of ATM activity in primary CLL cells proved that VUS-predicted pathogenic ATM variants partially reduce ATM activity and concurrent del(11q) leads to complete loss of ATM activity. The rare germline variants were associated with reduced progression-free survival in CLL on novel agents, comparable to somatic ATM or TP53 disruptions. Our results highlight the need to determine the pathogenicity of VUS in clinically relevant genes such as ATM.
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Affiliation(s)
- Anna Petrackova
- Department of Immunology, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic
| | - Jakub Savara
- Department of Immunology, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic.,Department of Computer Science, Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, Ostrava, Czech Republic
| | - Peter Turcsanyi
- Department of Hemato-Oncology, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic
| | - Petr Gajdos
- Department of Computer Science, Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, Ostrava, Czech Republic
| | - Tomas Papajik
- Department of Hemato-Oncology, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic
| | - Eva Kriegova
- Department of Immunology, Faculty of Medicine and Dentistry, Palacký University and University Hospital Olomouc, Olomouc, Czech Republic
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Vargason AB, Turner CE, Shriver CD, Ellsworth RE. Influence of germline test results on surgical decision making in women with invasive breast cancer. Cancer Genet 2022; 266-267:81-85. [PMID: 35868102 DOI: 10.1016/j.cancergen.2022.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/10/2022] [Accepted: 07/10/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND While therapeutic mastectomy with contralateral prophylactic mastectomy (TM+CPM) and/or bilateral salpingo-oophorectomy (BSO) are recommended for women with pathogenic variants (PV) in some cancer predisposition genes, evidence for the utility of these surgeries for women with PV in other genes currently is insufficient. In conjunction, current guidelines recommend that clinical management should not be influenced by a return of a variant of uncertain significance (VUS). Return of germline test results may, however, influence surgical decision making regardless of current guidelines. We thus evaluated surgical choices amongst a cohort of women with invasive breast cancer who underwent clinical genetic testing. METHODS Germline test results and all surgical procedures were extracted for women who had unilateral invasive breast cancer and had clinical testing before definitive surgery (n = 591). Results were classified as pathogenic/likely pathogenic (PV, 17.1%), VUS (19.5%) or benign/likely benign (63.4%). Data were analyzed using chi-square tests with p<0.05 defining significance. RESULTS Rates of TM+CPM and BSO were not significantly different for women with VUS compared to those with benign findings. Rates of TM+CPM were significantly higher for women with PV in BRCA1 and BRCA2, PALB2, PTEN and TP53, as well in genes with insufficient data to recommend risk-reducing mastectomy. Rates of BSO were significantly higher in women with PV in BRCA1 and BRCA2, PALB2, PTEN and TP53 and BRIP1, RAD51C and RAD51D compared to those with benign findings. CONCLUSION Overall, surgical choices for women with a VUS were more similar to those from women with benign variants than to those with PV, however, in the group with PV in genes for which insufficient evidence exists for the benefit of risk-reducing mastectomy, rates of TM+CPM were high. Thus, while the management of women with VUS is in agreement with ACMG guidelines, patients with mutations in other cancer genes demonstrate a preference for more aggressive breast surgeries.
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Affiliation(s)
- Ashlee B Vargason
- Breast Care Clinic, Department of Surgery, Walter Reed National Military Medical Center, 8901 Rockville Pike, Bethesda, MD 20889, USA.
| | - Clesson E Turner
- National Human Genome Research Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
| | - Craig D Shriver
- Murtha Cancer Center/Research Program, Uniformed Services University of the Health Sciences and Walter Reed National Military Medical Center, 8901 Rockville Pike, Bethesda, MD 20889, USA; Department of Surgery, Uniformed Services University of the Health Sciences, 8901 Rockville Pike, Bethesda, MD 20889, USA.
| | - Rachel E Ellsworth
- Murtha Cancer Center/Research Program, Uniformed Services University of the Health Sciences and Walter Reed National Military Medical Center, 8901 Rockville Pike, Bethesda, MD 20889, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Dr., Bethesda, MD 20817, USA.
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30
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Wai HA, Constable M, Drewes C, Davies IC, Svobodova E, Dempsey E, Saggar A, Homfray T, Mansour S, Douzgou S, Barr K, Mercer C, Hunt D, Douglas AGL, Baralle D. Short amplicon reverse transcription-polymerase chain reaction detects aberrant splicing in genes with low expression in blood missed by ribonucleic acid sequencing analysis for clinical diagnosis. Hum Mutat 2022; 43:963-970. [PMID: 35476365 PMCID: PMC9325405 DOI: 10.1002/humu.24378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/28/2022] [Accepted: 03/31/2022] [Indexed: 12/03/2022]
Abstract
Use of blood RNA sequencing (RNA-seq) as a splicing analysis tool for clinical interpretation of variants of uncertain significance (VUSs) found via whole-genome and exome sequencing can be difficult for genes that have low expression in the blood due to insufficient read count coverage aligned to specific genes of interest. Here, we present a short amplicon reverse transcription-polymerase chain reaction(RT-PCR) for the detection of genes with low blood expression. Short amplicon RT-PCR, is designed to span three exons where an exon harboring a variant is flanked by one upstream and one downstream exon. We tested short amplicon RT-PCRs for genes that have median transcripts per million (TPM) values less than one according to the genotype-tissue expression database. Median TPM values of genes analyzed in this study are SYN1 = 0.8549, COL1A1 = 0.6275, TCF4 = 0.4009, DSP = .2894, TTN = 0.2851, COL5A2 = 0.1036, TERT = 0.04452, NTRK2 = 0.0344, ABCA4 = 0.00744, PRPH = 0, and WT1 = 0. All these genes show insufficient exon-spanning read coverage in our RNA-seq data to allow splicing analysis. We successfully detected all genes tested except PRPH and WT1. Aberrant splicing was detected in SYN1, TCF4, NTRK2, TTN, and TERT VUSs. Therefore, our results show short amplicon RT-PCR is a useful alternative for the analysis of splicing events in genes with low TPM in blood RNA for clinical diagnostics.
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Affiliation(s)
- Htoo A. Wai
- Human Development and Health, Faculty of Medicine, Southampton General HospitalUniversity of SouthamptonSouthamptonUK
| | - Matthew Constable
- Human Development and Health, Faculty of Medicine, Southampton General HospitalUniversity of SouthamptonSouthamptonUK
| | - Cosima Drewes
- Human Development and Health, Faculty of Medicine, Southampton General HospitalUniversity of SouthamptonSouthamptonUK
| | - Ian C. Davies
- Human Development and Health, Faculty of Medicine, Southampton General HospitalUniversity of SouthamptonSouthamptonUK
| | - Eliska Svobodova
- Department of Experimental Biology, Faculty of ScienceMasaryk UniversityBrnoCzech Republic
| | - Esther Dempsey
- Department of Clinical GeneticsSt George's University of LondonLondonUK
| | - Anand Saggar
- Department of Clinical GeneticsSt George's University of LondonLondonUK
| | - Tessa Homfray
- Department of Clinical GeneticsSt George's University of LondonLondonUK
| | - Sahar Mansour
- Department of Clinical GeneticsSt George's University of LondonLondonUK
| | - Sofia Douzgou
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation TrustHealth Innovation ManchesterManchesterUK,Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, School of Biological SciencesUniversity of ManchesterManchesterUK
| | - Kate Barr
- Bristol Regional Clinical Genetics ServiceSt Michael's HospitalBristolUK
| | - Catherine Mercer
- Department of Experimental Biology, Faculty of ScienceMasaryk UniversityBrnoCzech Republic
| | - David Hunt
- Human Development and Health, Faculty of Medicine, Southampton General HospitalUniversity of SouthamptonSouthamptonUK,Wessex Clinical Genetics ServiceUniversity Hospital Southampton NHS Foundation TrustSouthamptonUK
| | - Andrew G. L. Douglas
- Human Development and Health, Faculty of Medicine, Southampton General HospitalUniversity of SouthamptonSouthamptonUK,Wessex Clinical Genetics ServiceUniversity Hospital Southampton NHS Foundation TrustSouthamptonUK
| | - Diana Baralle
- Human Development and Health, Faculty of Medicine, Southampton General HospitalUniversity of SouthamptonSouthamptonUK,Wessex Clinical Genetics ServiceUniversity Hospital Southampton NHS Foundation TrustSouthamptonUK
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Gervas P, Molokov A, Babyshkina N, Kiselev A, Zarubin A, Yumov E, Pisareva L, Choynzonov E, Cherdyntseva N. Pathogenicity Reclassification of Genetic Variants Related to Early-Onset Breast Cancer among Women of Mongoloid Origin. Asian Pac J Cancer Prev 2022; 23:2027-2033. [PMID: 35763645 PMCID: PMC9587833 DOI: 10.31557/apjcp.2022.23.6.2027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND Germline alterations in BRCA1, BRCA2, and other genes are responsible for early-onset breast cancer. However, up to 20% of molecular tests report genetic variant of unknown significance (VUS) or novel variants that have never been previously described and their clinical significance are unknown. This study aimed to reclassify variant of unknown significance (VUS) or novel variants by using the ActiveDriveDB database that annotates variants through the lens of sites of post-translational modifications (PTM). METHODS Our study included thirty-eighth young Buryat BC patients, belonging to the Mongoloid race and anthropologically to the Central Asia. Genomic DNA was extracted from the peripheral blood lymphocytes using the phenol/chloroform method. DNA library were prepared using the Hereditary Cancer SolutionTM kit (Sophia GENETICS, Switzerland) to cover 27 genes, such as ATM, APC, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, EPCAM, FAM175A, MLH1, MRE11A, MSH2, MSH6, MUTYH, NBN, PALB2, PIK3CA, PMS2, PMS2CL, PTEN, RAD50, RAD51C, RAD51D, STK11, TP53, and XRCC2. Paired-end sequencing (2 x 150 bp) was conducted using NextSeq 500 system (Illumina, USA). RESULTS We re-examined 135 rare variants (41 VUS, 25 conflicting, 64 benign and 5 new variants). We identified 10 out of 135 (7.4%) mutations that affected the sites of post-translational modification in proteins. Of 135 rare mutations, 1 benign variant was reclassified as network-rewiring - motif loss mutation, 3 VUS and 1 new variant were reclassified as distal PTM- mutations, 2 new and 1 benign variant were classified as proximal PTM- mutations and 1 benign and 1 conflicting variant were classified as direct PTM- mutations. CONCLUSIONS For the first time, 7.4% (10 out of 135) of mutations that affected the sites of post-translational modification in proteins were identified among early-onset breast cancer women of Mongoloid origin.
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Affiliation(s)
- Polina Gervas
- Department of Molecular oncology and Immunology, Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Science, Tomsk, Russia.
| | - Aleksey Molokov
- Department of Molecular oncology and Immunology, Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Science, Tomsk, Russia.
| | - Nataliya Babyshkina
- Department of Molecular oncology and Immunology, Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Science, Tomsk, Russia.
| | - Artem Kiselev
- Almazov National Medical Research Centre, St. Petersburg, Russia.
| | - Aleksei Zarubin
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russia.
| | - Evgeny Yumov
- Department of Surgery, GBUZ “Buryat Republican clinical oncology dispensary”, Republic of Buryatia, Ulan-Ude, Russia.
| | - Lubov Pisareva
- Department of Molecular oncology and Immunology, Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Science, Tomsk, Russia.
| | - Evgeny Choynzonov
- Department of Molecular oncology and Immunology, Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Science, Tomsk, Russia.
| | - Nadezda Cherdyntseva
- Department of Molecular oncology and Immunology, Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Science, Tomsk, Russia.
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Tallis E, Scollon S, Ritter DI, Plon SE. Evolution of germline TP53 variant classification in children with cancer. Cancer Genet 2022; 264-265:29-32. [PMID: 35306447 PMCID: PMC9133135 DOI: 10.1016/j.cancergen.2022.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 02/24/2022] [Accepted: 02/28/2022] [Indexed: 12/13/2022]
Abstract
Li-Fraumeni syndrome, caused by germline pathogenic variants in TP53, results in susceptibility to multiple cancers. Variants of uncertain significance (VUS) and reclassification of variants over time pose management concerns given improved survival with cancer surveillance for LFS patients. We describe the experience of TP53 variant reclassification at a pediatric cancer center. METHODS We reviewed medical records (2010-2019) of 756 patients seen in Texas Children's Cancer Genetics Clinic. We noted initial TP53 classification and any reclassifications. We then classified TP53 variants following ClinGen TP53 variant curation expert panel recommendations using data from ClinVar, medical literature and IARC database. RESULTS Of 234 patients tested for TP53, 27 (11.5%) reports contained pathogenic/likely pathogenic (P/LP) variants and 7 (3)% contained VUS. By January 2022, 4 of 6 unique VUS and 2 of 16 unique P/LP variants changed interpretations in ClinVar. Reinterpretation of these 4 VUS in ClinVar matched clinical decision at the time of initial report. Applying TP53 VCEP specifications classified 3 VUS to P/LP/benign, and one pathogenic variant to likely benign. CONCLUSIONS Planned review of variant significance is essential, especially for patients with high probability of LFS.
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Affiliation(s)
- E Tallis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - S Scollon
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States; Texas Children's Cancer Center, Texas Children's Hospital, Houston, TX, United States
| | - D I Ritter
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States; Texas Children's Cancer Center, Texas Children's Hospital, Houston, TX, United States
| | - S E Plon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States; Texas Children's Cancer Center, Texas Children's Hospital, Houston, TX, United States.
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33
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Massimino M, Stella S, Micale G, Motta L, Pavone G, Broggi G, Piombino E, Magro G, Soto Parra HJ, Manzella L, Vigneri P. Mechanistic Translation of Melanoma Genetic Landscape in Enriched Pathways and Oncogenic Protein-Protein Interactions. Cancer Genomics Proteomics 2022; 19:350-361. [PMID: 35430568 PMCID: PMC9016481 DOI: 10.21873/cgp.20325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND/AIM Malignant melanoma is a skin cancer originating from the oncogenic transformation of melanocytes located in the epidermal layers. Usually, the patient's prognosis depends on timing of disease detection and molecular and genetic profiling, which may all significantly influence mortality rates. Genetic analyses often detect somatic BRAF, NRAS and cKIT mutations, germline substitutions in CDKN2A, and alterations of the PI3K-AKT-PTEN pathway. A peculiar molecular future of melanoma is its high immunogenicity, making this tumor targetable by programmed cell death protein 1-specific antibodies. MATERIALS AND METHODS Ten formalin-fixed paraffin embedded samples derived from melanoma patients were subjected to next-generation sequencing (NGS) analysis using the FDA-approved FoundationOne CDx™ test. The molecular features of each case were then analyzed employing several in silico prediction tools. RESULTS We analyzed the mutational landscape of patients with metastatic or relapsed cutaneous melanoma to define enriched pathways and protein-protein interactions. The analysis showed that both known genetic alterations and variants of unknown significance rely on redundant signaling converging on similar gene ontology biological processes. Complex informatics analyses of NGS-based genetic results identified pivotal signaling pathways that could provide additional targets for cancer treatment. CONCLUSION Our data suggest an additional role for NGS in melanoma, as analysis of comprehensive genetic findings using innovative informatic tools may lengthen the list of druggable molecular targets that impact patient outcome.
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Affiliation(s)
- Michele Massimino
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy;
- Center of Experimental Oncology and Hematology, A.O.U. Policlinico "G. Rodolico - S. Marco", Catania, Italy
| | - Stefania Stella
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
- Center of Experimental Oncology and Hematology, A.O.U. Policlinico "G. Rodolico - S. Marco", Catania, Italy
| | - Giovanni Micale
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Lucia Motta
- Center of Experimental Oncology and Hematology, A.O.U. Policlinico "G. Rodolico - S. Marco", Catania, Italy
- Medical Oncology, A.O.U. "G. Rodolico - S. Marco", Catania, Italy
| | - Giuliana Pavone
- Center of Experimental Oncology and Hematology, A.O.U. Policlinico "G. Rodolico - S. Marco", Catania, Italy
- Medical Oncology, A.O.U. "G. Rodolico - S. Marco", Catania, Italy
| | - Giuseppe Broggi
- Department of Medical, Surgical Sciences and Advanced Technologies "G.F. Ingrassia", Anatomic Pathology, University of Catania, Catania, Italy
| | - Eliana Piombino
- Pathology Unit, Department of Experimental Oncology, Mediterranean Institute of Oncology, Viagrande, Italy
| | - Gaetano Magro
- Department of Medical, Surgical Sciences and Advanced Technologies "G.F. Ingrassia", Anatomic Pathology, University of Catania, Catania, Italy
| | | | - Livia Manzella
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
- Center of Experimental Oncology and Hematology, A.O.U. Policlinico "G. Rodolico - S. Marco", Catania, Italy
| | - Paolo Vigneri
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
- Center of Experimental Oncology and Hematology, A.O.U. Policlinico "G. Rodolico - S. Marco", Catania, Italy
- Medical Oncology, A.O.U. "G. Rodolico - S. Marco", Catania, Italy
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Abdel-Razeq H, Tamimi F, Abujamous L, Abdel-Razeq R, Abunasser M, Edaily S, Abdulelah H, Khashabeh RA, Bater R. Rates of Variants of Uncertain Significance Among Patients With Breast Cancer Undergoing Genetic Testing: Regional Perspectives. Front Oncol 2022; 12:673094. [PMID: 35402282 PMCID: PMC8989924 DOI: 10.3389/fonc.2022.673094] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 02/25/2022] [Indexed: 11/22/2022] Open
Abstract
Purpose Contrary to BRCA pathogenic variants, recommendations for management of variants of uncertain significance (VUS) are not clear and focus more on the patient’s family and personal history of cancer. Local and regional data on VUS are scarce. In this paper, we study patterns and frequency of VUS among breast cancer patients undergoing genetic testing. Patients and Methods Patients with breast cancer at high risk for pathogenic variants, as per the National Comprehensive Cancer Network (NCCN) guidelines, were tested at reference laboratories. Related surgical interventions were reviewed. Results Among a group of 1,197 patients with breast cancer who underwent genetic testing and counseling, 110 (9.2%) had VUS; most (n = 79, 71.8%) were in BRCA2. Median age (range) was 39 (25–66) years with 65 (59.1%) patients who were 40 years or younger at diagnosis. Among 103 patients with non-metastatic disease, 48 (46.6%) had breast-conserving surgery (BCS) while only 5 (4.9%) had bilateral mastectomies; all were due to bilateral disease and not prophylactic. VUS diagnosis was known prior to initial surgery in 34 (33.0%) patients; 11 (32.4%) of them had BCS only. Over the study period, only one VUS variant was upgraded to “likely positive.” The recent introduction of multiple-gene panel testing had resulted in a surge in VUS rate (22.2%) in genes other than BRCA1 or BRCA2, like PALB2, CHEK2, and ATM. Conclusions Rates of VUS are relatively high and increasing, mostly in non-BRCA1 or BRCA2, and this had no impact on the therapeutic or prophylactic surgical decisions. Adherence to guidelines is extremely important to avoid unnecessary procedures.
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Affiliation(s)
- Hikmat Abdel-Razeq
- Department of Medicine, King Hussein Cancer Center, Amman, Jordan.,School of Medicine, University of Jordan, Amman, Jordan
| | - Faris Tamimi
- Department of Medicine, King Hussein Cancer Center, Amman, Jordan
| | - Lama Abujamous
- Department of Cell Therapy & Applied Genomic, King Hussein Cancer Center, Amman, Jordan
| | | | | | - Sara Edaily
- Department of Medicine, King Hussein Cancer Center, Amman, Jordan
| | - Hazem Abdulelah
- Department of Medicine, King Hussein Cancer Center, Amman, Jordan
| | - Razan Abu Khashabeh
- Department of Cell Therapy & Applied Genomic, King Hussein Cancer Center, Amman, Jordan
| | - Rayan Bater
- Department of Medicine, King Hussein Cancer Center, Amman, Jordan
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35
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Khan MA, Siddiqui MQ, Kuligina E, Varma AK. Evaluation of conformational transitions of h-BRCA2 functional domain and unclassified variant Arg2502Cys using multimodal approach. Int J Biol Macromol 2022; 209:716-724. [PMID: 35413318 DOI: 10.1016/j.ijbiomac.2022.04.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 04/02/2022] [Accepted: 04/06/2022] [Indexed: 11/26/2022]
Abstract
Breast cancer type 2 susceptibility (BRCA2) protein plays an essential role in the repair mechanism of DNA double-strand breaks and interstrand cross-links by Homologous recombination. Germline mutations identified in the BRCA2 gene confer an increased risk of hereditary breast and ovarian cancer. Missense mutations are identified all over the gene, including the DNA binding region of BRCA2 that interacts with FANCD2. However, the majority of these missense mutations are classified as 'Variants of Uncertain Significance' due to a lack of structural, functional and clinical correlations. Therefore, multi-disciplinary in-silico, in-vitro and biophysical approaches have been explored to characterize an unclassified missense mutation, BRCA2 Arg2502Cys, identified from a case-control study. Circular-dichroism and Fluorescence spectroscopy show that the Arg2502Cys mutation in hBRCA2 (residues 2350-2545) decreases the α-helical/β-sheet propensity of the wild-type protein and perturb the tertiary structure conformation. Molecular dynamics simulations revealed alteration in the intramolecular H-bonds, overall compactness and stability of the hydrophobic core were observed in the mutant protein. Principle component analysis indicated that Arg2502Cys mutant exhibited comparatively large conformational transitions and periodic fluctuation. Therefore, to our conclusion, BRCA2 Arg2502Cys mutant perturbed the structural integrity and conformational dynamics of BRCA2.
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Affiliation(s)
- Mudassar Ali Khan
- Advanced Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai, Maharashtra 410210, India; Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
| | - M Quadir Siddiqui
- Advanced Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai, Maharashtra 410210, India; Present address: Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Ekaterina Kuligina
- N.N. Petrov Institute of Oncology, Laboratory of Molecular Oncology, RU-197758, Pesochny-2, St.-Petersburg, Russia
| | - Ashok K Varma
- Advanced Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai, Maharashtra 410210, India; Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India.
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Vagrecha A, Zhang M, Acharya S, Lozinsky S, Singer A, Levine C, Al-Ghafry M, Fein Levy C, Cron RQ. Hemophagocytic Lymphohistiocytosis Gene Variants in Multisystem Inflammatory Syndrome in Children. Biology (Basel) 2022; 11:417. [PMID: 35336791 DOI: 10.3390/biology11030417] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/02/2022] [Accepted: 03/07/2022] [Indexed: 12/20/2022]
Abstract
Simple Summary Children with a COVID-19 infection are at risk of developing a novel syndrome called multisystem inflammatory syndrome in children (MIS-C). This disease state is characterized by a high level of inflammation. It is unclear why only some children infected with SARS-CoV-2 later develop MIS-C. There may be genetic risk factors for MIS-C development, but none have previously been reported. We report genetic findings in a group of children with MIS-C. Abstract Multisystem inflammatory syndrome in children (MIS-C) affects few children previously infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In 2020, 45 children admitted to our hospital for MIS-C underwent genetic screening with a commercial 109-immune-gene panel. Thirty-nine children were diagnosed with MIS-C, and 25.4% of the 39 MIS-C patients harbored rare heterozygous missense mutations either in primary hemophagocytic lymphohistiocytosis (pHLH) genes (LYST, STXBP2, PRF1, UNC13D, AP3B1) or the HLH-associated gene DOCK8 (four variants). We demonstrate that foamy virus introduction of cDNA for the four DOCK8 variants into human NK-92 natural killer (NK) cells led to decreased CD107a expression (degranulation) and decreased NK cell lytic function in vitro for each variant. Heterozygous carriers of missense mutations in pHLH genes and DOCK8 may serve as risk factors for development of MIS-C among children previously infected with SARS-CoV-2.
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Valenzuela‐Palomo A, Bueno‐Martínez E, Sanoguera‐Miralles L, Lorca V, Fraile‐Bethencourt E, Esteban‐Sánchez A, Gómez‐Barrero S, Carvalho S, Allen J, García‐Álvarez A, Pérez‐Segura P, Dorling L, Easton DF, Devilee P, Vreeswijk MPG, de la Hoya M, Velasco EA. Splicing predictions, minigene analyses, and ACMG-AMP clinical classification of 42 germline PALB2 splice-site variants. J Pathol 2022; 256:321-334. [PMID: 34846068 PMCID: PMC9306493 DOI: 10.1002/path.5839] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 11/18/2021] [Accepted: 11/26/2021] [Indexed: 12/18/2022]
Abstract
PALB2 loss-of-function variants confer high risk of developing breast cancer. Here we present a systematic functional analysis of PALB2 splice-site variants detected in approximately 113,000 women in the large-scale sequencing project Breast Cancer After Diagnostic Gene Sequencing (BRIDGES; https://bridges-research.eu/). Eighty-two PALB2 variants at the intron-exon boundaries were analyzed with MaxEntScan. Forty-two variants were selected for the subsequent splicing functional assays. For this purpose, three splicing reporter minigenes comprising exons 1-12 were constructed. The 42 potential spliceogenic variants were introduced into the minigenes by site-directed mutagenesis and assayed in MCF-7/MDA-MB-231 cells. Splicing anomalies were observed in 35 variants, 23 of which showed no traces or minimal amounts of the expected full-length transcripts of each minigene. More than 30 different variant-induced transcripts were characterized, 23 of which were predicted to truncate the PALB2 protein. The pathogenicity of all variants was interpreted according to an in-house adaptation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG-AMP) variant classification scheme. Up to 23 variants were classified as pathogenic/likely pathogenic. Remarkably, three ±1,2 variants (c.49-2A>T, c.108+2T>C, and c.211+1G>A) were classified as variants of unknown significance, as they produced significant amounts of either in-frame transcripts of unknown impact on the PALB2 protein function or the minigene full-length transcripts. In conclusion, we have significantly contributed to the ongoing effort of identifying spliceogenic variants in the clinically relevant PALB2 cancer susceptibility gene. Moreover, we suggest some approaches to classify the findings in accordance with the ACMG-AMP rationale. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Alberto Valenzuela‐Palomo
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética MolecularConsejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
| | - Elena Bueno‐Martínez
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética MolecularConsejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
| | - Lara Sanoguera‐Miralles
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética MolecularConsejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
| | - Víctor Lorca
- Molecular Oncology Laboratory, Hospital Clínico San CarlosIdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos)MadridSpain
| | - Eugenia Fraile‐Bethencourt
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética MolecularConsejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
- Knight Cancer Research BuildingPortlandORUSA
| | - Ada Esteban‐Sánchez
- Molecular Oncology Laboratory, Hospital Clínico San CarlosIdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos)MadridSpain
| | | | - Sara Carvalho
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary CareUniversity of CambridgeCambridgeUK
| | - Jamie Allen
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary CareUniversity of CambridgeCambridgeUK
| | - Alicia García‐Álvarez
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética MolecularConsejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
| | - Pedro Pérez‐Segura
- Molecular Oncology Laboratory, Hospital Clínico San CarlosIdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos)MadridSpain
| | - Leila Dorling
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary CareUniversity of CambridgeCambridgeUK
| | - Douglas F Easton
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary CareUniversity of CambridgeCambridgeUK
| | - Peter Devilee
- Department of Human GeneticsLeiden University Medical CenterLeidenThe Netherlands
| | - Maaike PG Vreeswijk
- Department of Human GeneticsLeiden University Medical CenterLeidenThe Netherlands
| | - Miguel de la Hoya
- Molecular Oncology Laboratory, Hospital Clínico San CarlosIdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos)MadridSpain
| | - Eladio A Velasco
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética MolecularConsejo Superior de Investigaciones Científicas (CSIC‐UVa)ValladolidSpain
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Fanale D, Pivetti A, Cancelliere D, Spera A, Bono M, Fiorino A, Pedone E, Barraco N, Brando C, Perez A, Guarneri MF, Russo TDB, Vieni S, Guarneri G, Russo A, Bazan V. BRCA1/2 variants of unknown significance in hereditary breast and ovarian cancer (HBOC) syndrome: looking for the hidden meaning. Crit Rev Oncol Hematol 2022; 172:103626. [PMID: 35150867 DOI: 10.1016/j.critrevonc.2022.103626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 01/04/2023] Open
Abstract
Hereditary breast and ovarian cancer syndrome is caused by germline mutations in BRCA1/2 genes. These genes are very large and their mutations are heterogeneous and scattered throughout the coding sequence. In addition to the above-mentioned mutations, variants of uncertain/unknown significance (VUSs) have been identified in BRCA genes, which make more difficult the clinical management of the patient and risk assessment. In the last decades, several laboratories have developed different databases that contain more than 2000 variants for the two genes and integrated strategies which include multifactorial prediction models based on direct and indirect genetic evidence, to classify the VUS and attribute them a clinical significance associated with a deleterious, high-low or neutral risk. This review provides a comprehensive overview of literature studies concerning the VUSs, in order to assess their impact on the population and provide new insight for the appropriate patient management in clinical practice.
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Affiliation(s)
- Daniele Fanale
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Alessia Pivetti
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Daniela Cancelliere
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Antonio Spera
- Department of Radiotherapy, San Giovanni di Dio Hospital, ASP of Agrigento, Agrigento, Italy
| | - Marco Bono
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Alessia Fiorino
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Erika Pedone
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Nadia Barraco
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Chiara Brando
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Alessandro Perez
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | | | - Tancredi Didier Bazan Russo
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Salvatore Vieni
- Division of General and Oncological Surgery, Department of Surgical, Oncological and Oral Sciences, University of Palermo, Italy
| | - Girolamo Guarneri
- Gynecology Section, Mother - Child Department, University of Palermo, 90127 Palermo, Italy
| | - Antonio Russo
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy.
| | - Viviana Bazan
- Department of Biomedicine, Neuroscience and Advanced Diagnostics, University of Palermo, 90127 Palermo, Italy
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Charron JG, Hernandez A, Bilinovich SM, Vogt DL, Bedinger LA, Seaver LH, Williams M, Devries S, Campbell DB, Bupp CP, Prokop JW. N-methyl-d-aspartate (NMDA) receptor genetics: The power of paralog homology and protein dynamics in defining dominant genetic variants. Am J Med Genet A 2022; 188:556-568. [PMID: 34726335 PMCID: PMC10472328 DOI: 10.1002/ajmg.a.62554] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/05/2021] [Accepted: 10/07/2021] [Indexed: 11/08/2022]
Abstract
Predicting genotype-to-phenotype correlations from genomic variants has been challenging, particularly for genes that have a complex balance of dominant and recessive inheritance for phenotypes. Variants in NMDA receptor components GRIN1, GRIN2A, and GRIN2B cause a myriad of dominant disease phenotypes, with the most common being epilepsy and autism spectrum disorder. Starting from the analysis of a variant of uncertain significance (VUS, GRIN2A G760S), we realized the need for tools to map dominant variants for the components of the NMDA receptor. Some variants within GRIN1, GRIN2A, and GRIN2B exert dominant epilepsy and developmental delay, yet other amino acid variants are conserved and predicted to alter protein function but do not have dominant phenotypes. Common variant annotation tools are not powered to determine pathogenic dominant outcomes. To address this gap, we integrated sequence and structural analyses for GRIN1, GRIN2A, and GRIN2B. Using this approach, we determined that paralog homology mapping and topology can segregate dominant variants, with an elevation of intermolecular contacts between the subunits. Furthermore, demonstrating the general utility of our methodology, we show that 25 VUS within ClinVar also reach a dominant variant annotation, including the GRIN2A G760S variant. Our work suggests paralog homology and protein topology as a powerful strategy within the receptor complex to resolve dominant genetic variants relative to variants that would fit a recessive inheritance, requiring two damaging variants. These strategies should be tested in additional dominant genetic disorders to determine the broader utility.
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Affiliation(s)
- Jacob G Charron
- Department of Pediatrics & Human Development, Michigan State University, Grand Rapids, MI. 49503
- Department of Biology, Calvin University, Grand Rapids MI 49506, USA
| | - Angel Hernandez
- Pediatric Neurology, Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
| | - Stephanie M Bilinovich
- Department of Pediatrics & Human Development, Michigan State University, Grand Rapids, MI. 49503
- Center for Research in Autism, Intellectual, and other Neurodevelopmental Disabilities, Michigan State University, East Lansing, MI, 48824, USA
| | - Daniel L Vogt
- Department of Pediatrics & Human Development, Michigan State University, Grand Rapids, MI. 49503
- Center for Research in Autism, Intellectual, and other Neurodevelopmental Disabilities, Michigan State University, East Lansing, MI, 48824, USA
| | - Laura A Bedinger
- Division of Medical Genetics, Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
| | - Laurie H Seaver
- Department of Pediatrics & Human Development, Michigan State University, Grand Rapids, MI. 49503
- Division of Medical Genetics, Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
| | - Michael Williams
- Department of Pediatrics & Human Development, Michigan State University, Grand Rapids, MI. 49503
- Center for Research in Autism, Intellectual, and other Neurodevelopmental Disabilities, Michigan State University, East Lansing, MI, 48824, USA
| | - Seth Devries
- Pediatric Neurology, Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
| | - Daniel B Campbell
- Department of Pediatrics & Human Development, Michigan State University, Grand Rapids, MI. 49503
- Center for Research in Autism, Intellectual, and other Neurodevelopmental Disabilities, Michigan State University, East Lansing, MI, 48824, USA
| | - Caleb P Bupp
- Department of Pediatrics & Human Development, Michigan State University, Grand Rapids, MI. 49503
- Division of Medical Genetics, Helen DeVos Children’s Hospital, Grand Rapids, MI 49503, USA
| | - Jeremy W Prokop
- Department of Pediatrics & Human Development, Michigan State University, Grand Rapids, MI. 49503
- Center for Research in Autism, Intellectual, and other Neurodevelopmental Disabilities, Michigan State University, East Lansing, MI, 48824, USA
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, 48824, USA
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Prendergast A, Ziganshin BA, Papanikolaou D, Zafar MA, Nicoli S, Mukherjee S, Elefteriades JA. Phenotyping Zebrafish Mutant Models to Assess Candidate Genes Associated with Aortic Aneurysm. Genes (Basel) 2022; 13:123. [PMID: 35052463 PMCID: PMC8775119 DOI: 10.3390/genes13010123] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/15/2021] [Accepted: 01/07/2022] [Indexed: 02/06/2023] Open
Abstract
(1) Background: Whole Exome Sequencing of patients with thoracic aortic aneurysm often identifies "Variants of Uncertain Significance" (VUS), leading to uncertainty in clinical management. We assess a novel mechanism for potential routine assessment of these genes in TAA patients. Zebrafish are increasingly used as experimental models of disease. Advantages include low cost, rapid maturation, and physical transparency, permitting direct microscopic assessment. (2) Methods: Zebrafish loss of function mutations were generated using a CRISPRC/CAS9 approach for EMILIN1 and MIB1 genes similar to VUSs identified in clinical testing. Additionally, "positive control" mutants were constructed for known deleterious variants in FBN1 (Marfan's) and COL1A2, COL5A1, COL5A2 (Ehlers-Danlos). Zebrafish embryos were followed to six days post-fertilization. Embryos were studied by brightfield and confocal microscopy to ascertain any vascular, cardiac, and skeletal abnormalities. (3) Results: A dramatic pattern of cardiac, cerebral, aortic, and skeletal abnormalities was identified for the known pathogenic FBN1 and COL1A2, COL5A1, and COL5A2 mutants, as well as for the EMILIN1 and MIB1 mutants of prior unknown significance. Visualized abnormalities included hemorrhage (peri-aortic and cranial), cardiomegaly, reduced diameter of the aorta and intersegmental vessels, lower aortic cell counts, and scoliosis (often extremely severe). (4) Conclusion: This pilot study suggests that candidate genes arising in clinical practice may be rapidly assessed via zebrafish mutants-thus permitting evidence-based decisions about pathogenicity. Thus, years-long delays to clinically demonstrate pathogenicity may be obviated. Zebrafish data would represent only one segment of analysis, which would also include frequency of the variant in the general population, in silico genetic analysis, and degree of preservation in phylogeny.
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Affiliation(s)
- Andrew Prendergast
- Yale Zebrafish Phenotyping Core, Yale University School of Medicine, New Haven, CT 06510, USA; (A.P.); (S.N.)
| | - Bulat A. Ziganshin
- Aortic Institute at Yale-New Haven, Yale University School of Medicine, New Haven, CT 06510, USA; (B.A.Z.); (D.P.); (M.A.Z.); (S.M.)
| | - Dimitra Papanikolaou
- Aortic Institute at Yale-New Haven, Yale University School of Medicine, New Haven, CT 06510, USA; (B.A.Z.); (D.P.); (M.A.Z.); (S.M.)
| | - Mohammad A. Zafar
- Aortic Institute at Yale-New Haven, Yale University School of Medicine, New Haven, CT 06510, USA; (B.A.Z.); (D.P.); (M.A.Z.); (S.M.)
| | - Stefania Nicoli
- Yale Zebrafish Phenotyping Core, Yale University School of Medicine, New Haven, CT 06510, USA; (A.P.); (S.N.)
- Yale Cardiovascular Research Center, Cardiology, Internal Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Sandip Mukherjee
- Aortic Institute at Yale-New Haven, Yale University School of Medicine, New Haven, CT 06510, USA; (B.A.Z.); (D.P.); (M.A.Z.); (S.M.)
| | - John A. Elefteriades
- Aortic Institute at Yale-New Haven, Yale University School of Medicine, New Haven, CT 06510, USA; (B.A.Z.); (D.P.); (M.A.Z.); (S.M.)
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Long A, Crouse A, Kesterson RA, Might M, Wallis D. Functional characterization and potential therapeutic avenues for variants in the NTRK2 gene causing developmental and epileptic encephalopathies. Am J Med Genet B Neuropsychiatr Genet 2022; 189:37-47. [PMID: 34889524 DOI: 10.1002/ajmg.b.32882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 10/29/2021] [Accepted: 11/22/2021] [Indexed: 01/11/2023]
Abstract
Variants within the Neurotrophic Tyrosine Kinase Receptor Type 2 (NTRK2) gene have been discovered to play a role in developmental and epileptic encephalopathies, a group of debilitating conditions for which little is known about cause or treatment. Here, we determine the functional consequences of two variants: p.Tyr434Cys (Y434C) (located in the transmembrane domain) and p.Thr720Ile (T720I) (located in the catalytic domain). Wild-type and variant cDNAs were constructed and transfected into HEK293 cells. In cell culture, variant Y434C exhibited ligand-independent activation of tropomyosin-related kinase B (TRKB) signaling with an associated abnormal response to brain-derived neurotrophic factor (BDNF) stimulation and increased levels of phosphorylated extracellular signal-regulated kinase (ERK) and ETS like-1 protein (ELK1) activity. Expression of variant T720I resulted in decreased TRKB signaling with reduced mTor activity as determined by decreased levels of phosphorylated S6. With the deleterious mechanisms characterized, we utilized mediKanren (a novel artificial intelligence tool) to identify therapeutics to compensate for the pathological effects. Downregulation of TRKB through inhibition with mediKanren-predicted compound 1NM-PP1 led to decreased MEK activity. Upregulation of TRKB signaling by mediKanren-predicted valproic acid led to subsequent increase of mTor activity. Overall, our results provide further characterization of the pathogenicity of these two variants in the NTRK2 gene. Indeed, Y434C is the first patient-specific NTRK2 variant with demonstrated hypermorphic activity. Furthermore, we observed that variants Y434C and T720I result in distinct functional consequences that require distinct therapeutic strategies. These data suggest the possibility that unique mutations within different regions of the NTRK2 gene results in separate clinical presentations, representing distinct genetic disorders requiring unique therapeutics.
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Affiliation(s)
- Ashlee Long
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Andrew Crouse
- Personalized Medicine Institute, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Robert A Kesterson
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Matthew Might
- Personalized Medicine Institute, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Deeann Wallis
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Tsutakawa SE, Bacolla A, Katsonis P, Bralić A, Hamdan SM, Lichtarge O, Tainer JA, Tsai CL. Decoding Cancer Variants of Unknown Significance for Helicase-Nuclease-RPA Complexes Orchestrating DNA Repair During Transcription and Replication. Front Mol Biosci 2021; 8:791792. [PMID: 34966786 PMCID: PMC8710748 DOI: 10.3389/fmolb.2021.791792] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 11/16/2021] [Indexed: 01/13/2023] Open
Abstract
All tumors have DNA mutations, and a predictive understanding of those mutations could inform clinical treatments. However, 40% of the mutations are variants of unknown significance (VUS), with the challenge being to objectively predict whether a VUS is pathogenic and supports the tumor or whether it is benign. To objectively decode VUS, we mapped cancer sequence data and evolutionary trace (ET) scores onto crystallography and cryo-electron microscopy structures with variant impacts quantitated by evolutionary action (EA) measures. As tumors depend on helicases and nucleases to deal with transcription/replication stress, we targeted helicase–nuclease–RPA complexes: (1) XPB-XPD (within TFIIH), XPF-ERCC1, XPG, and RPA for transcription and nucleotide excision repair pathways and (2) BLM, EXO5, and RPA plus DNA2 for stalled replication fork restart. As validation, EA scoring predicts severe effects for most disease mutations, but disease mutants with low ET scores not only are likely destabilizing but also disrupt sophisticated allosteric mechanisms. For sites of disease mutations and VUS predicted to be severe, we found strong co-localization to ordered regions. Rare discrepancies highlighted the different survival requirements between disease and tumor mutations, as well as the value of examining proteins within complexes. In a genome-wide analysis of 33 cancer types, we found correlation between the number of mutations in each tumor and which pathways or functional processes in which the mutations occur, revealing different mutagenic routes to tumorigenesis. We also found upregulation of ancient genes including BLM, which supports a non-random and concerted cancer process: reversion to a unicellular, proliferation-uncontrolled, status by breaking multicellular constraints on cell division. Together, these genes and global analyses challenge the binary “driver” and “passenger” mutation paradigm, support a gradient impact as revealed by EA scoring from moderate to severe at a single gene level, and indicate reduced regulation as well as activity. The objective quantitative assessment of VUS scoring and gene overexpression in the context of functional interactions and pathways provides insights for biology, oncology, and precision medicine.
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Affiliation(s)
- Susan E Tsutakawa
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX, United States
| | - Panagiotis Katsonis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Amer Bralić
- Laboratory of DNA Replication and Recombination, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Samir M Hamdan
- Laboratory of DNA Replication and Recombination, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Olivier Lichtarge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - John A Tainer
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.,Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX, United States.,Department of Cancer Biology, University of Texas M.D. Anderson Cancer Center, Houston, TX, United States
| | - Chi-Lin Tsai
- Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX, United States
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Bains S, Dotzler SM, Krijger C, Giudicessi JR, Ye D, Bikker H, Rohatgi RK, Tester DJ, Bos JM, Wilde AAM, Ackerman MJ. A phenotype-enhanced variant classification framework to decrease the burden of missense variants of uncertain significance in type 1 long QT syndrome. Heart Rhythm 2021; 19:435-442. [PMID: 34798354 DOI: 10.1016/j.hrthm.2021.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Pathogenic/likely pathogenic (P/LP) variants in the KCNQ1-encoded Kv7.1 potassium channel cause type 1 long QT syndrome (LQT1). Despite the revamped 2015 American College of Medical Genetics (ACMG) variant interpretation guidelines, the burden of KCNQ1 variants of uncertain significance (VUS) in patients with LQTS remains ∼30%. OBJECTIVE The purpose of this study was to determine whether a phenotype-enhanced (PE) variant classification approach could reduce the VUS burden in LQTS genetic testing. METHODS Retrospective analysis was performed on 79 KCNQ1 missense variants in 356 patients from Mayo Clinic and an independent cohort of 42 variants in 225 patients from Amsterdam University Medical Center (UMC). Each variant was classified initially using the ACMG guidelines and then readjudicated using a PE-ACMG framework that incorporated the LQTS clinical diagnostic Schwartz score plus 4 "LQT1-defining features": broad-based/slow upstroke T waves, syncope/seizure during exertion, swimming-associated events, and a maladaptive LQT1 treadmill stress test. RESULTS According to the ACMG guidelines, Mayo Clinic variants were classified as follows: 17 of 79 P variants (22%), 34 of 79 LP variants (43%), and 28 of 79 VUS (35%). Similarly, for Amsterdam UMC, the variant distribution was 9 of 42 P variants (22%), 14 of 42 LP variants (33%), and 19 of 42 variants VUS (45%). After PE-ACMG readjudication, the total VUS burden decreased significantly from 28 (35%) to 13 (16%) (P = .0007) for Mayo Clinic and from 19 (45%) to 12 (29%) (P = .02) for Amsterdam UMC. CONCLUSION Phenotype-guided variant adjudication decreased significantly the VUS burden of LQT1 case-derived KCNQ1 missense variants in 2 independent cohorts. This study demonstrates the value of incorporating LQT1-specific phenotype/clinical data to aid in the interpretation of KCNQ1 missense variants identified during genetic testing for LQTS.
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Affiliation(s)
- Sahej Bains
- Medical Scientist Training Program, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Steven M Dotzler
- Medical Scientist Training Program, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Christian Krijger
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - John R Giudicessi
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota
| | - Dan Ye
- Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Hennie Bikker
- Department of Human Genetics, University of Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Ram K Rohatgi
- Department of Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), Mayo Clinic, Rochester, Minnesota
| | - David J Tester
- Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota; Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), Mayo Clinic, Rochester, Minnesota
| | - J Martijn Bos
- Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota; Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), Mayo Clinic, Rochester, Minnesota
| | - Arthur A M Wilde
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Cardiology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Michael J Ackerman
- Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota; Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), Mayo Clinic, Rochester, Minnesota.
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44
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Long A, Liu H, Liu J, Daniel M, Bedwell DM, Korf B, Kesterson RA, Wallis D. Analysis of patient-specific NF1 variants leads to functional insights for Ras signaling that can impact personalized medicine. Hum Mutat 2021; 43:30-41. [PMID: 34694046 DOI: 10.1002/humu.24290] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/13/2021] [Accepted: 10/19/2021] [Indexed: 01/04/2023]
Abstract
We have created a panel of 29 NF1 variant complementary DNAs (cDNAs) representing missense variants, many with clinically relevant phenotypes, in-frame deletions, splice variants, and nonsense variants. We have determined the functional consequences of the variants, assessing their ability to produce mature neurofibromin and restore Ras signaling activity in NF1 null (-/-) cells. cDNAs demonstrate variant-specific differences in neurofibromin protein levels, suggesting that some variants lead to neurofibromatosis type 1 (NF1) gene or protein instability or enhanced degradation. When expressed at high levels, some variant proteins are still able to repress Ras activity, indicating that the NF1 phenotype may be due to low protein abundance. In contrast, other variant proteins are incapable of repressing Ras activity, indicating that some do not functionally engage Ras and stimulate GTPase activity. We observed that effects on protein abundance and Ras activity can be mutually exclusive. These assays allow us to categorize variants by functional effects, may help to classify variants of unknown significance, and may have future implications for more directed therapeutics.
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Affiliation(s)
- Ashlee Long
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Hui Liu
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jian Liu
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Michael Daniel
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - David M Bedwell
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Bruce Korf
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Robert A Kesterson
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Deeann Wallis
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
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45
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Tam B, Sinha S, Qin Z, Wang SM. Comprehensive Identification of Deleterious TP53 Missense VUS Variants Based on Their Impact on TP53 Structural Stability. Int J Mol Sci 2021; 22:11345. [PMID: 34768775 PMCID: PMC8583684 DOI: 10.3390/ijms222111345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 11/30/2022] Open
Abstract
TP53 plays critical roles in maintaining genome stability. Deleterious genetic variants damage the function of TP53, causing genome instability and increased cancer risk. Of the large quantity of genetic variants identified in TP53, however, many remain functionally unclassified as variants of unknown significance (VUS) due to the lack of evidence. This is reflected by the presence of 749 (42%) VUS of the 1785 germline variants collected in the ClinVar database. In this study, we addressed the deleteriousness of TP53 missense VUS. Utilizing the protein structure-based Ramachandran Plot-Molecular Dynamics Simulation (RPMDS) method that we developed, we measured the effects of missense VUS on TP53 structural stability. Of the 340 missense VUS tested, we observed deleterious evidence for 193 VUS, as reflected by the TP53 structural changes caused by the VUS-substituted residues. We compared the results from RPMDS with those from other in silico methods and observed higher specificity of RPMDS in classification of TP53 missense VUS than these methods. Data from our current study address a long-standing challenge in classifying the missense VUS in TP53, one of the most important tumor suppressor genes.
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Affiliation(s)
| | | | | | - San Ming Wang
- Cancer Centre and Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Taipa, Macau 999078, China; (B.T.); (S.S.); (Z.Q.)
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46
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Mauro-Herrera M, Chiang J, Radojevic B, Bennett LD. Functional Evaluation of Splicing for Variants of Uncertain Significance in Patients with Inherited Retinal Diseases. Genes (Basel) 2021; 12:993. [PMID: 34209753 DOI: 10.3390/genes12070993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 01/13/2023] Open
Abstract
Inherited retinal diseases (IRD) comprise a heterogeneous set of clinical and genetic disorders that lead to blindness. Given the emerging opportunities in precision medicine and gene therapy, it has become increasingly important to determine whether DNA variants with uncertain significance (VUS) are responsible for patients’ IRD. This research was performed to assess the functional consequence of six VUS identified in patients with IRD. Clinical assessments included an ophthalmic examination, best-corrected visual acuity, and kinetic perimetry. Imaging was acquired with the Optos ultra-widefield camera and spectral domain optical coherence tomography (SD-OCT). Genetic testing was performed by Molecular Vision Laboratories. VUS that were predicted to alter splicing were analyzed with a minigene assay, which revealed that VUS in the genes OPA1, CNGB1, and CLUAP1 altered spicing mechanisms. Due to emerging gene and cell therapies, these results expand the genotype-phenotype correlations for patients diagnosed with an IRD.
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47
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Chevrier S, Richard C, Collot T, Mananet H, Arnould L, Boidot R. An Algorithm Combining Patient Performance Status, Second Hit Analysis, PROVEAN and Dann Prediction Tools Could Foretell Sensitization to PARP Inhibitors in Digestive, Skin, Ovarian and Breast Cancers. Cancers (Basel) 2021; 13:cancers13133113. [PMID: 34206535 PMCID: PMC8268870 DOI: 10.3390/cancers13133113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/14/2021] [Accepted: 06/21/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary PARP inhibitors, a family of targeted cancer therapeutics, have been shown to be efficient in patients with some deficiencies in the homologous recombination machinery. However, a quick and reliable identification of patients who would benefit from such therapies remains a challenge. In particular, patients with tumors carrying variants of unknown significance (VUS) in homologous recombination genes do not currently benefit from PARP inhibitor treatments. In this study, we present an algorithm that may allow classification of these variants with regard to their impact on tumor responsiveness to PARP inhibitors. If validated on a larger patient sample, our algorithm would allow patients with tumors potentially responsive to PARP inhibitors to benefit from this therapy. Abstract PARP inhibitors yield interesting outcomes for patients with ovarian tumors harboring BRCA1 or BRCA2 mutation, but also with other tumors with homologous repair (HR) deficiency. About 40% of variants are variants of unknown significance (VUS), blocking the use of PARP inhibitors. In this study, we analyzed NGS data from 78 metastatic patients treated with PARP inhibitors. We tested NGS data and in silico predictions to classify VUS as potentially benign or deleterious. Among 41 patients treated with olaparib, three had tumors harboring benign and 26 pathogenic variants, while 12 had VUS. Progression-Free Survival (PFS) analysis showed that benign variants did not respond to olaparib whereas pathogenic variants were associated with a median PFS of 190 days. Surprisingly, median PFS of patients with VUS-carrying tumors suggested that some of them may be sensitive to PARP inhibitors. By testing different in silico predictions and variant allelic frequency, we obtained an algorithm predicting VUS sensitivity to PARP inhibitors for patients with a Performance Status below 3. Our work suggests that VUS in HR genes could be predicted as benign or deleterious, which may increase the number of patients eligible for PARP inhibitor treatment. Further studies in a larger sample are warranted to validate our prediction algorithm.
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Affiliation(s)
- Sandy Chevrier
- Department of Biology and Pathology of Tumors, Georges-François Leclerc Cancer Center-UNICANCER, 21079 Dijon, France; (S.C.); (C.R.); (L.A.)
| | - Corentin Richard
- Department of Biology and Pathology of Tumors, Georges-François Leclerc Cancer Center-UNICANCER, 21079 Dijon, France; (S.C.); (C.R.); (L.A.)
| | - Thomas Collot
- Department of Medical Oncology, Georges-François Leclerc Cancer Center-UNICANCER, 21079 Dijon, France;
| | - Hugo Mananet
- Platform of Transfer in Cancer Biology, Georges-François Leclerc Cancer Center-UNICANCER, 21079 Dijon, France;
| | - Laurent Arnould
- Department of Biology and Pathology of Tumors, Georges-François Leclerc Cancer Center-UNICANCER, 21079 Dijon, France; (S.C.); (C.R.); (L.A.)
| | - Romain Boidot
- Department of Biology and Pathology of Tumors, Georges-François Leclerc Cancer Center-UNICANCER, 21079 Dijon, France; (S.C.); (C.R.); (L.A.)
- UMR CNRS 6302, University of Burgundy, 21079 Dijon, France
- Correspondence: ; Tel.: +33-3-80-73-77-67; Fax: +33-3-80-73-77-82
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48
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Pham DH, Pitman MR, Kumar R, Jolly LA, Schulz R, Gardner AE, de Nys R, Heron SE, Corbett MA, Kothur K, Gill D, Rajagopalan S, Kolc KL, Halliday BJ, Robertson SP, Regan BM, Kirsch HE, Berkovic SF, Scheffer IE, Pitson SM, Petrovski S, Gecz J. Integrated in silico and experimental assessment of disease relevance of PCDH19 missense variants. Hum Mutat 2021; 42:1030-1041. [PMID: 34082468 DOI: 10.1002/humu.24237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 03/27/2021] [Accepted: 05/31/2021] [Indexed: 11/09/2022]
Abstract
PCDH19 is a nonclustered protocadherin molecule involved in axon bundling, synapse function, and transcriptional coregulation. Pathogenic variants in PCDH19 cause infantile-onset epilepsy known as PCDH19-clustering epilepsy or PCDH19-CE. Recent advances in DNA-sequencing technologies have led to a significant increase in the number of reported PCDH19-CE variants, many of uncertain significance. We aimed to determine the best approaches for assessing the disease relevance of missense variants in PCDH19. The application of the American College of Medical Genetics and Association for Molecular Pathology (ACMG-AMP) guidelines was only 50% accurate. Using a training set of 322 known benign or pathogenic missense variants, we identified MutPred2, MutationAssessor, and GPP as the best performing in silico tools. We generated a protein structural model of the extracellular domain and assessed 24 missense variants. We also assessed 24 variants using an in vitro reporter assay. A combination of these tools was 93% accurate in assessing known pathogenic and benign PCDH19 variants. We increased the accuracy of the ACMG-AMP classification of 45 PCDH19 variants from 50% to 94%, using these tools. In summary, we have developed a robust toolbox for the assessment of PCDH19 variant pathogenicity to improve the accuracy of PCDH19-CE variant classification.
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Affiliation(s)
- Duyen H Pham
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.,Paediatrics and Reproductive Health, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Melissa R Pitman
- Molecular Therapeutics, Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
| | - Raman Kumar
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.,Paediatrics and Reproductive Health, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Lachlan A Jolly
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.,Paediatrics and Reproductive Health, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Renee Schulz
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Alison E Gardner
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.,Paediatrics and Reproductive Health, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Rebekah de Nys
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.,Paediatrics and Reproductive Health, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Sarah E Heron
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.,Paediatrics and Reproductive Health, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Mark A Corbett
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.,Paediatrics and Reproductive Health, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Kavitha Kothur
- Department of Paediatrics and Child Health, Kids Neuroscience Centre, The University of Sydney, Sydney, New South Wales, Australia.,TY Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Deepak Gill
- Department of Paediatrics and Child Health, Kids Neuroscience Centre, The University of Sydney, Sydney, New South Wales, Australia.,TY Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Sulekha Rajagopalan
- Department of Clinical Genetics, Liverpool Hospital, Liverpool, New South Wales, Australia
| | - Kristy L Kolc
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.,Paediatrics and Reproductive Health, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - Benjamin J Halliday
- Department of Women's and Children's Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Stephen P Robertson
- Department of Women's and Children's Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Brigid M Regan
- Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia
| | - Heidi E Kirsch
- Department of Neurology, University of California, San Francisco, California, USA
| | - Samuel F Berkovic
- Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia
| | - Ingrid E Scheffer
- Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia.,Department of Paediatrics, Royal Children's Hospital, University of Melbourne, Flemington, Victoria, Australia.,Epilepsy Research Centre, Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, Australia
| | - Stuart M Pitson
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.,Molecular Therapeutics, Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia.,School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Slave Petrovski
- Centre for Genomics Research, Precision Medicine and Genomics, IMED Biotech Unit, AstraZeneca, Cambridge, UK.,Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Jozef Gecz
- Neurogenetics, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.,Paediatrics and Reproductive Health, Robinson Research Institute, The University of Adelaide, Adelaide, South Australia, Australia.,School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia.,Women and Kids, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
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49
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Bueno-Martínez E, Sanoguera-Miralles L, Valenzuela-Palomo A, Lorca V, Gómez-Sanz A, Carvalho S, Allen J, Infante M, Pérez-Segura P, Lázaro C, Easton DF, Devilee P, Vreeswijk MPG, de la Hoya M, Velasco EA. RAD51D Aberrant Splicing in Breast Cancer: Identification of Splicing Regulatory Elements and Minigene-Based Evaluation of 53 DNA Variants. Cancers (Basel) 2021; 13:2845. [PMID: 34200360 PMCID: PMC8201001 DOI: 10.3390/cancers13112845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/01/2021] [Accepted: 06/03/2021] [Indexed: 12/18/2022] Open
Abstract
RAD51D loss-of-function variants increase lifetime risk of breast and ovarian cancer. Splicing disruption is a frequent pathogenic mechanism associated with variants in susceptibility genes. Herein, we have assessed the splicing and clinical impact of splice-site and exonic splicing enhancer (ESE) variants identified through the study of ~113,000 women of the BRIDGES cohort. A RAD51D minigene with exons 2-9 was constructed in splicing vector pSAD. Eleven BRIDGES splice-site variants (selected by MaxEntScan) were introduced into the minigene by site-directed mutagenesis and tested in MCF-7 cells. The 11 variants disrupted splicing, collectively generating 25 different aberrant transcripts. All variants but one produced negligible levels (<3.4%) of the full-length (FL) transcript. In addition, ESE elements of the alternative exon 3 were mapped by testing four overlapping exonic microdeletions (≥30-bp), revealing an ESE-rich interval (c.202_235del) with critical sequences for exon 3 recognition that might have been affected by germline variants. Next, 26 BRIDGES variants and 16 artificial exon 3 single-nucleotide substitutions were also assayed. Thirty variants impaired splicing with variable amounts (0-65.1%) of the FL transcript, although only c.202G>A demonstrated a complete aberrant splicing pattern without the FL transcript. On the other hand, c.214T>C increased efficiency of exon 3 recognition, so only the FL transcript was detected (100%). In conclusion, 41 RAD51D spliceogenic variants (28 of which were from the BRIDGES cohort) were identified by minigene assays. We show that minigene-based mapping of ESEs is a powerful approach for identifying ESE hotspots and ESE-disrupting variants. Finally, we have classified nine variants as likely pathogenic according to ACMG/AMP-based guidelines, highlighting the complex relationship between splicing alterations and variant interpretation.
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Affiliation(s)
- Elena Bueno-Martínez
- Splicing and Genetic Susceptibility to Cancer Laboratory, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (A.V.-P.)
| | - Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer Laboratory, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (A.V.-P.)
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer Laboratory, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (A.V.-P.)
| | - Víctor Lorca
- Molecular Oncology Laboratory CIBERONC, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Hospital Clinico San Carlos, 28040 Madrid, Spain; (V.L.); (A.G.-S.); (P.P.-S.)
| | - Alicia Gómez-Sanz
- Molecular Oncology Laboratory CIBERONC, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Hospital Clinico San Carlos, 28040 Madrid, Spain; (V.L.); (A.G.-S.); (P.P.-S.)
| | - Sara Carvalho
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Jamie Allen
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Mar Infante
- Cancer Genetics, Unidad de Excelencia Instituto de Biología y Genética Molecular (CSIC-UVa), 47003 Valladolid, Spain;
| | - Pedro Pérez-Segura
- Molecular Oncology Laboratory CIBERONC, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Hospital Clinico San Carlos, 28040 Madrid, Spain; (V.L.); (A.G.-S.); (P.P.-S.)
| | - Conxi Lázaro
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL and CIBERONC, 08908 Hospitalet de Llobregat, Spain;
| | - Douglas F. Easton
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Peter Devilee
- Department of Human Genetics, Leiden University Medical Center, 2300RC Leiden, The Netherlands; (P.D.); (M.P.G.V.)
| | - Maaike P. G. Vreeswijk
- Department of Human Genetics, Leiden University Medical Center, 2300RC Leiden, The Netherlands; (P.D.); (M.P.G.V.)
| | - Miguel de la Hoya
- Molecular Oncology Laboratory CIBERONC, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Hospital Clinico San Carlos, 28040 Madrid, Spain; (V.L.); (A.G.-S.); (P.P.-S.)
| | - Eladio A. Velasco
- Splicing and Genetic Susceptibility to Cancer Laboratory, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (A.V.-P.)
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50
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Favalli V, Tini G, Bonetti E, Vozza G, Guida A, Gandini S, Pelicci PG, Mazzarella L. Machine learning-based reclassification of germline variants of unknown significance: The RENOVO algorithm. Am J Hum Genet 2021; 108:682-695. [PMID: 33761318 DOI: 10.1016/j.ajhg.2021.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/01/2021] [Indexed: 01/20/2023] Open
Abstract
The increasing scope of genetic testing allowed by next-generation sequencing (NGS) dramatically increased the number of genetic variants to be interpreted as pathogenic or benign for adequate patient management. Still, the interpretation process often fails to deliver a clear classification, resulting in either variants of unknown significance (VUSs) or variants with conflicting interpretation of pathogenicity (CIP); these represent a major clinical problem because they do not provide useful information for decision-making, causing a large fraction of genetically determined disease to remain undertreated. We developed a machine learning (random forest)-based tool, RENOVO, that classifies variants as pathogenic or benign on the basis of publicly available information and provides a pathogenicity likelihood score (PLS). Using the same feature classes recommended by guidelines, we trained RENOVO on established pathogenic/benign variants in ClinVar (training set accuracy = 99%) and tested its performance on variants whose interpretation has changed over time (test set accuracy = 95%). We further validated the algorithm on additional datasets including unreported variants validated either through expert consensus (ENIGMA) or laboratory-based functional techniques (on BRCA1/2 and SCN5A). On all datasets, RENOVO outperformed existing automated interpretation tools. On the basis of the above validation metrics, we assigned a defined PLS to all existing ClinVar VUSs, proposing a reclassification for 67% with >90% estimated precision. RENOVO provides a validated tool to reduce the fraction of uninterpreted or misinterpreted variants, tackling an area of unmet need in modern clinical genetics.
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Affiliation(s)
- Valentina Favalli
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Giulia Tini
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Emanuele Bonetti
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Gianluca Vozza
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Alessandro Guida
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy; Biomedical Translational Imaging Centre, Nova Scotia Health Authority and IWK Health Centre, Halifax, NS B3K 6R8, Canada
| | - Sara Gandini
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Pier Giuseppe Pelicci
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Luca Mazzarella
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy.
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