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Munté E, Feliubadaló L, Del Valle J, González S, Ramos-Muntada M, Balmaña J, Ramon Y Cajal T, Tuset N, Llort G, Cadiñanos J, Brunet J, Capellá G, Lázaro C, Pineda M. Open-Source Bioinformatic Pipeline to Improve PMS2 Genetic Testing Using Short-Read NGS Data. J Mol Diagn 2024; 26:727-738. [PMID: 38851388 DOI: 10.1016/j.jmoldx.2024.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 05/03/2024] [Accepted: 05/13/2024] [Indexed: 06/10/2024] Open
Abstract
The molecular diagnosis of mismatch repair-deficient cancer syndromes is hampered by difficulties in sequencing the PMS2 gene, mainly owing to the PMS2CL pseudogene. Next-generation sequencing short reads cannot be mapped unambiguously by standard pipelines, compromising variant calling accuracy. This study aimed to provide a refined bioinformatic pipeline for PMS2 mutational analysis and explore PMS2 germline pathogenic variant prevalence in an unselected hereditary cancer (HC) cohort. PMS2 mutational analysis was optimized using two cohorts: 192 unselected HC patients for assessing the allelic ratio of paralogous sequence variants, and 13 samples enriched with PMS2 (likely) pathogenic variants screened previously by long-range genomic DNA PCR amplification. Reads were forced to align with the PMS2 reference sequence, except those corresponding to exon 11, where only those intersecting gene-specific invariant positions were considered. Afterward, the refined pipeline's accuracy was validated in a cohort of 40 patients and used to screen 5619 HC patients. Compared with our routine diagnostic pipeline, the PMS2_vaR pipeline showed increased technical sensitivity (0.853 to 0.956, respectively) in the validation cohort, identifying all previously PMS2 pathogenic variants found by long-range genomic DNA PCR amplification. Fifteen HC cohort samples carried a pathogenic PMS2 variant (15 of 5619; 0.285%), doubling the estimated prevalence in the general population. The refined open-source approach improved PMS2 mutational analysis accuracy, allowing its inclusion in the routine next-generation sequencing pipeline streamlining PMS2 screening.
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Affiliation(s)
- Elisabet Munté
- Hereditary Cancer Program, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain; Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Spain
| | - Lídia Feliubadaló
- Hereditary Cancer Program, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain; Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Spain; Ciber Oncología, Instituto Salud Carlos III, Madrid, Spain
| | - Jesús Del Valle
- Hereditary Cancer Program, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain; Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Spain; Ciber Oncología, Instituto Salud Carlos III, Madrid, Spain
| | - Sara González
- Hereditary Cancer Program, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain; Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Spain
| | - Mireia Ramos-Muntada
- Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Spain; Ciber Oncología, Instituto Salud Carlos III, Madrid, Spain
| | - Judith Balmaña
- High Risk and Cancer Prevention Group, Vall d'Hebron Institute of Oncology, Barcelona, Spain; Medical Oncology Department, University Hospital of Vall d'Hebron, Barcelona, Spain
| | - Teresa Ramon Y Cajal
- Familial Cancer Clinic, Medical Oncology Service, Hospital Sant Pau, Barcelona, Spain
| | - Noemí Tuset
- Medical Oncology Department, Hospital Universitari Arnau de Vilanova, Lleida, Spain
| | - Gemma Llort
- Department of Medical Oncology Parc Taulí, Hospital Universitari Parc Taulí Sabadell, Barcelona, Spain
| | - Juan Cadiñanos
- R&D Laboratory, Fundación Centro Médico de Asturias-IMOMA, Oviedo, Spain
| | - Joan Brunet
- Hereditary Cancer Program, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain; Ciber Oncología, Instituto Salud Carlos III, Madrid, Spain; Precision Oncology Group (OncoGir_Pro), Institut d'Investigació Biomèdica de Girona, Girona, Spain
| | - Gabriel Capellá
- Hereditary Cancer Program, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain; Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Spain; Ciber Oncología, Instituto Salud Carlos III, Madrid, Spain
| | - Conxi Lázaro
- Hereditary Cancer Program, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain; Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Spain; Ciber Oncología, Instituto Salud Carlos III, Madrid, Spain.
| | - Marta Pineda
- Hereditary Cancer Program, Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain; Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge, L'Hospitalet de Llobregat, Spain; Ciber Oncología, Instituto Salud Carlos III, Madrid, Spain.
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2
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Bouras A, Lefol C, Ruano E, Grand-Masson C, Wang Q. PMS2 or PMS2CL? Characterization of variants detected in the 3' of the PMS2 gene. Genes Chromosomes Cancer 2024; 63:e23193. [PMID: 37534630 DOI: 10.1002/gcc.23193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/04/2023] Open
Abstract
PMS2 germline pathogenic variants are one of the major causes for Lynch syndrome and constitutional mismatch repair deficiencies. Variant identification in the 3' region of this gene is complicated by the presence of the pseudogene PMS2CL which shares a high sequence homology with PMS2. Consequently, short-fragment screening strategies (NGS, Sanger) may fail to discriminate variant's gene localization. Using a comprehensive analysis strategy, we assessed 42 NGS-detected variants in 76 patients and found 32 localized on PMS2 while 6 on PMS2CL. Interestingly, four variants were detected in either of them in different patients. Clinical phenotype was well correlated to genotype, making it very helpful in variant assessment. Our findings emphasize the necessity of more specific complementary analyses to confirm the gene origin of each variant detected in different individuals in order to avoid variant misinterpretation. In addition, we characterized two PMS2 genomic alterations involving Alu-mediated tandem duplication and gene conversion. Those mechanisms seemed to be particularly favored in PMS2 which contribute to frequent genomic rearrangements in the 3' region of the gene.
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Affiliation(s)
- Ahmed Bouras
- Centre Léon Bérard, Laboratory of Constitutional Genetics for Frequent Cancer HCL-CLB, Lyon, France
- Inserm U1052, Centre de Recherche en Cancérologie de Lyon, Lyon, France
| | - Cedrick Lefol
- Centre Léon Bérard, Laboratory of Constitutional Genetics for Frequent Cancer HCL-CLB, Lyon, France
| | - Eric Ruano
- Centre Léon Bérard, Laboratory of Constitutional Genetics for Frequent Cancer HCL-CLB, Lyon, France
| | - Chloé Grand-Masson
- Centre Léon Bérard, Laboratory of Constitutional Genetics for Frequent Cancer HCL-CLB, Lyon, France
| | - Qing Wang
- Centre Léon Bérard, Laboratory of Constitutional Genetics for Frequent Cancer HCL-CLB, Lyon, France
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3
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Rojahn S, Hambuch T, Adrian J, Gafni E, Gileta A, Hatchell H, Johnson B, Kallman B, Karfilis K, Kautzer C, Kennemer M, Kirk L, Kvitek D, Lettes J, Macrae F, Mendez F, Paul J, Pellegrino M, Preciado R, Risinger J, Schultz M, Spurka L, Swamy S, Truty R, Usem N, Velenich A, Aradhya S. Scalable detection of technically challenging variants through modified next-generation sequencing. Mol Genet Genomic Med 2022; 10:e2072. [PMID: 36251442 PMCID: PMC9747563 DOI: 10.1002/mgg3.2072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 09/23/2022] [Accepted: 09/30/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Some clinically important genetic variants are not easily evaluated with next-generation sequencing (NGS) methods due to technical challenges arising from high- similarity copies (e.g., PMS2, SMN1/SMN2, GBA1, HBA1/HBA2, CYP21A2), repetitive short sequences (e.g., ARX polyalanine repeats, FMR1 AGG interruptions in CGG repeats, CFTR poly-T/TG repeats), and other complexities (e.g., MSH2 Boland inversions). METHODS We customized our NGS processes to detect the technically challenging variants mentioned above with adaptations including target enrichment and bioinformatic masking of similar sequences. Adaptations were validated with samples of known genotypes. RESULTS Our adaptations provided high-sensitivity and high-specificity detection for most of the variants and provided a high-sensitivity primary assay to be followed with orthogonal disambiguation for the others. The sensitivity of the NGS adaptations was 100% for all of the technically challenging variants. Specificity was 100% for those in PMS2, GBA1, SMN1/SMN2, and HBA1/HBA2, and for the MSH2 Boland inversion; 97.8%-100% for CYP21A2 variants; and 85.7% for ARX polyalanine repeats. CONCLUSIONS NGS assays can detect technically challenging variants when chemistries and bioinformatics are jointly refined. The adaptations described support a scalable, cost-effective path to identifying all clinically relevant variants within a single sample.
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4
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Srinivasan P, Bandlamudi C, Jonsson P, Kemel Y, Chavan SS, Richards AL, Penson AV, Bielski CM, Fong C, Syed A, Jayakumaran G, Prasad M, Hwee J, Sumer SO, de Bruijn I, Li X, Gao J, Schultz N, Cambria R, Galle J, Mukherjee S, Vijai J, Cadoo KA, Carlo MI, Walsh MF, Mandelker D, Ceyhan-Birsoy O, Shia J, Zehir A, Ladanyi M, Hyman DM, Zhang L, Offit K, Robson ME, Solit DB, Stadler ZK, Berger MF, Taylor BS. The context-specific role of germline pathogenicity in tumorigenesis. Nat Genet 2021; 53:1577-1585. [PMID: 34741162 PMCID: PMC8957388 DOI: 10.1038/s41588-021-00949-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 09/09/2021] [Indexed: 11/08/2022]
Abstract
Human cancers arise from environmental, heritable and somatic factors, but how these mechanisms interact in tumorigenesis is poorly understood. Studying 17,152 prospectively sequenced patients with cancer, we identified pathogenic germline variants in cancer predisposition genes, and assessed their zygosity and co-occurring somatic alterations in the concomitant tumors. Two major routes to tumorigenesis were apparent. In carriers of pathogenic germline variants in high-penetrance genes (5.1% overall), lineage-dependent patterns of biallelic inactivation led to tumors exhibiting mechanism-specific somatic phenotypes and fewer additional somatic oncogenic drivers. Nevertheless, 27% of cancers in these patients, and most tumors in patients with pathogenic germline variants in lower-penetrance genes, lacked particular hallmarks of tumorigenesis associated with the germline allele. The dependence of tumors on pathogenic germline variants is variable and often dictated by both penetrance and lineage, a finding with implications for clinical management.
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Affiliation(s)
- Preethi Srinivasan
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Stanford University School of Medicine, Palo Alto, CA, USA
| | - Chaitanya Bandlamudi
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Philip Jonsson
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Yelena Kemel
- Robert and Kate Niehaus Center for Inherited Cancer Genomics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Shweta S Chavan
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Allison L Richards
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Alexander V Penson
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Craig M Bielski
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Christopher Fong
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Aijazuddin Syed
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Gowtham Jayakumaran
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Meera Prasad
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jason Hwee
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Selcuk Onur Sumer
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ino de Bruijn
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Xiang Li
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - JianJiong Gao
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Nikolaus Schultz
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Roy Cambria
- Research and Technology Management, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jesse Galle
- Research and Technology Management, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Semanti Mukherjee
- Robert and Kate Niehaus Center for Inherited Cancer Genomics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Joseph Vijai
- Robert and Kate Niehaus Center for Inherited Cancer Genomics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Karen A Cadoo
- Robert and Kate Niehaus Center for Inherited Cancer Genomics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Maria I Carlo
- Robert and Kate Niehaus Center for Inherited Cancer Genomics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Michael F Walsh
- Robert and Kate Niehaus Center for Inherited Cancer Genomics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Diana Mandelker
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ozge Ceyhan-Birsoy
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jinru Shia
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ahmet Zehir
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Marc Ladanyi
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - David M Hyman
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Loxo Oncology, Stamford, CT, USA
| | - Liying Zhang
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Kenneth Offit
- Robert and Kate Niehaus Center for Inherited Cancer Genomics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Mark E Robson
- Robert and Kate Niehaus Center for Inherited Cancer Genomics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - David B Solit
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Zsofia K Stadler
- Robert and Kate Niehaus Center for Inherited Cancer Genomics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Michael F Berger
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Barry S Taylor
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Loxo Oncology, Stamford, CT, USA
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5
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Sharma R, Lewis S, Wlodarski MW. DNA Repair Syndromes and Cancer: Insights Into Genetics and Phenotype Patterns. Front Pediatr 2020; 8:570084. [PMID: 33194896 PMCID: PMC7644847 DOI: 10.3389/fped.2020.570084] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 09/18/2020] [Indexed: 12/15/2022] Open
Abstract
DNA damage response is essential to human physiology. A broad spectrum of pathologies are displayed by individuals carrying monoallelic or biallelic loss-of-function mutations in DNA damage repair genes. DNA repair syndromes with biallelic disturbance of essential DNA damage response pathways manifest early in life with multi-systemic involvement and a high propensity for hematologic and solid cancers, as well as bone marrow failure. In this review, we describe classic biallelic DNA repair cancer syndromes arising from faulty single- and double-strand DNA break repair, as well as dysfunctional DNA helicases. These clinical entities include xeroderma pigmentosum, constitutional mismatch repair deficiency, ataxia telangiectasia, Nijmegen breakage syndrome, deficiencies of DNA ligase IV, NHEJ/Cernunnos, and ERCC6L2, as well as Bloom, Werner, and Rothmund-Thompson syndromes. To give an in-depth understanding of these disorders, we provide historical overview and discuss the interplay between complex biology and heterogeneous clinical manifestations.
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Affiliation(s)
- Richa Sharma
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN, United States
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Sara Lewis
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Marcin W. Wlodarski
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN, United States
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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6
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Determining the impact of uncharacterized inversions in the human genome by droplet digital PCR. Genome Res 2020; 30:724-735. [PMID: 32424072 PMCID: PMC7263195 DOI: 10.1101/gr.255273.119] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 04/17/2020] [Indexed: 12/20/2022]
Abstract
Despite the interest in characterizing genomic variation, the presence of large repeats at the breakpoints hinders the analysis of many structural variants. This is especially problematic for inversions, since there is typically no gain or loss of DNA. Here, we tested novel linkage-based droplet digital PCR (ddPCR) assays to study 20 inversions ranging from 3.1 to 742 kb flanked by inverted repeats (IRs) up to 134 kb long. Of those, we validated 13 inversions predicted by different genome-wide techniques. In addition, we obtained new experimental human population information across 95 African, European, and East Asian individuals for 16 inversions, including four already validated variants without high-throughput genotyping methods. Through comparison with previous data, independent replicates and both inversion breakpoints, we demonstrate that the technique is highly accurate and reproducible. Most studied inversions are widespread across continents, and their frequency is negatively correlated with genetic length. Moreover, all except two show clear signs of being recurrent, and we could better define the factors affecting recurrence levels and estimate the inversion rate across the genome. Finally, the generated genotypes have allowed us to check inversion functional effects, validating gene expression differences reported before for two inversions and finding new candidate associations. Therefore, the developed methodology makes it possible to screen these and other complex genomic variants quickly in a large number of samples for the first time, highlighting the importance of direct genotyping to assess their potential consequences and clinical implications.
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7
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Jarhelle E, Riise Stensland HMF, Hansen GÅM, Skarsfjord S, Jonsrud C, Ingebrigtsen M, Strømsvik N, Van Ghelue M. Identifying sequence variants contributing to hereditary breast and ovarian cancer in BRCA1 and BRCA2 negative breast and ovarian cancer patients. Sci Rep 2019; 9:19986. [PMID: 31882575 PMCID: PMC6934654 DOI: 10.1038/s41598-019-55515-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/26/2019] [Indexed: 12/21/2022] Open
Abstract
Families with breast and ovarian cancer are often tested for disease associated sequence variants in BRCA1 and BRCA2. Pathogenic sequence variants (PVs) in these two genes are known to increase breast and ovarian cancer risks in females. However, in most families no PVs are detected in these two genes. Currently, several studies have identified other genes involved in hereditary breast and ovarian cancer (HBOC). To identify genetic risk factors for breast and ovarian cancer in a Norwegian HBOC cohort, 101 breast and/or ovarian cancer patients negative for PVs and variants of unknown clinical significance (VUS) in BRCA1/2 were screened for PVs in 94 genes using next-generation sequencing. Sixteen genes were closely scrutinized. Nine different deleterious germline PVs/likely pathogenic variants (LPVs) were identified in seven genes in 12 patients: three in ATM, and one in CHEK2, ERCC5, FANCM, RAD51C, TP53 and WRN. Additionally, 32 different VUSs were identified and these require further characterization. For carriers of PV/LPV in many of these genes, there are no national clinical management programs in Norway. The diversity of genetic risk factors possibly involved in cancer development show the necessity for more knowledge to improve the clinical follow-up of this genetically diverse patient group.
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Affiliation(s)
- Elisabeth Jarhelle
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway. .,Department of Clinical Medicine, University of Tromsø, Tromsø, Norway. .,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway.
| | - Hilde Monica Frostad Riise Stensland
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway.,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway
| | - Geir Åsmund Myge Hansen
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway.,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway
| | - Siri Skarsfjord
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway
| | - Christoffer Jonsrud
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway.,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway
| | - Monica Ingebrigtsen
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway
| | - Nina Strømsvik
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway.,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway.,Department of Health and Caring Sciences, Western Norway University of Applied Sciences, Bergen, Norway
| | - Marijke Van Ghelue
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway. .,Department of Clinical Medicine, University of Tromsø, Tromsø, Norway. .,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway.
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8
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Jansen AML, Tops CMJ, Ruano D, van Eijk R, Wijnen JT, Ten Broeke S, Nielsen M, Hes FJ, van Wezel T, Morreau H. The complexity of screening PMS2 in DNA isolated from formalin-fixed paraffin-embedded material. Eur J Hum Genet 2019; 28:333-338. [PMID: 31616036 DOI: 10.1038/s41431-019-0527-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 09/19/2019] [Accepted: 09/27/2019] [Indexed: 11/09/2022] Open
Abstract
Germline variants in the DNA mismatch repair (MMR) gene PMS2 cause 1-14% of all Lynch Syndrome cancers. Correct variant analysis of PMS2 is complex due to the presence of multiple pseudogenes and the occurrence of gene conversion. The analysis complexity increases in highly fragmented DNA from formalin-fixed paraffin-embedded (FFPE) tissue. Here we describe a reliable approach to detect true PMS2 variants in fragmented DNA. A custom NGS panel designed for FFPE tissue was used targeting four MMR genes, POLE and POLD1. Amplicon design for PMS2 was based on the position of paralogous sequence variants (PSVs) that distinguish PMS2 from its pseudogenes. PMS2 variants in exons 1-11 can be correctly curated based on this information. For exons 12-15 this is less reliable as these undergo gene conversion. Using this method, we screened PMS2 variants in 125 MMR-deficient tumors. Of the 125 tumors tested, six were unexplained MMR-deficient tumors with solitary PMS2 protein expression loss. In these six tumors two unclassified variants (class 3) and five variants likely affecting function (class 4/5) were detected in PMS2. One microsatellite unstable tumor with positive staining for all MMR proteins was found to carry a frameshift PMS2 variant (class 5). No class 4 or class 5 PMS2 variants were detected in tumors with other patterns of MMR protein expression loss.
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Affiliation(s)
- Anne M L Jansen
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Carli M J Tops
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Dina Ruano
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ronald van Eijk
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Juul T Wijnen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Sanne Ten Broeke
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Maartje Nielsen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Frederik J Hes
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Tom van Wezel
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Hans Morreau
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
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9
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Okkels H, Lagerstedt-Robinsson K, Wikman FP, Hansen TVO, Lolas I, Lindberg LJ, Krarup HB. Detection of PMS2 Mutations by Screening Hereditary Nonpolyposis Colon Cancer Families from Denmark and Sweden. Genet Test Mol Biomarkers 2019; 23:688-695. [PMID: 31433215 DOI: 10.1089/gtmb.2018.0316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Background and Aims: Hereditary nonpolyposis colon cancer (HNPCC) and Lynch syndrome (LS) are characterized by defects in the mismatch repair (MMR) system, which protects the integrity of the genome. Pathogenic variants in four MMR genes (MLH1, MSH2, MSH6, and PMS2) are responsible for LS, an autosomal, dominant hereditary disease that occurs with a frequency of 2-5% among all colorectal cancer cases. It has been estimated that ∼2-5% of all pathogenic variants found in the four MMR genes in LS cases are detected in the PMS2 gene. An overview of detected variants is presented here. Materials and Methods: Long-range (LR) PMS2 polymerase chain reaction (PCR) and PMS2 multiplex ligation probe amplification (MLPA) assays were used to detect PMS2 variants in ∼1500 probands. In a subset of the probands, pathogenic PMS2 variants were detected by next-generation sequencing, and all detected variants were confirmed by LR-PCR combined with an MLPA assay. Results: A summary of PMS2 mutation analyses performed on colon cancer patients from molecular diagnostic laboratories in Denmark and Sweden is presented. By screening ∼1500 HNPCC probands, a total of 40 different PMS2 variants were detected in 71 probands (5%); 20 variants were classified as pathogenic (C5), 2 variants as likely pathogenic (C4), 15 variants as variants of unknown significance (VUSs) (C3), 1 variant as likely benign (C2), and 2 variants as benign (C1). In total, 22/71 (31%) of the probands carried a pathogenic sequence variant. Among the probands with isolated loss of pPMS2 expression, the fraction of pathogenic variants was 20/35 (55%). Conclusions: Approximately 5% of the probands found in the Danish and Swedish populations presented here carried a PMS2 variant. In this study, six novel pathogenic variants and seven VUSs are reported.
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Affiliation(s)
- Henrik Okkels
- Section of Molecular Diagnostics, Department of Clinical Chemistry, Aalborg University Hospital, Aalborg, Denmark
| | - Kristina Lagerstedt-Robinsson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Friedrik P Wikman
- Department of Molecular Medicine (MOMA), Århus University Hospital, Århus, Denmark
| | - Thomas V O Hansen
- Department of Clinical Genetics, University Hospital of Copenhagen, Copenhagen, Denmark.,Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Ihab Lolas
- Section of Molecular Diagnostics, Department of Clinical Chemistry, Aalborg University Hospital, Aalborg, Denmark
| | - Lars Joachim Lindberg
- The Danish HNPCC Registry, Clinical Research Centre, Copenhagen University Hospital, Hvidovre, Denmark
| | - Henrik B Krarup
- Section of Molecular Diagnostics, Department of Clinical Chemistry, Aalborg University Hospital, Aalborg, Denmark
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10
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Morak M, Schaefer K, Steinke-Lange V, Koehler U, Keinath S, Massdorf T, Mauracher B, Rahner N, Bailey J, Kling C, Haeusser T, Laner A, Holinski-Feder E. Full-length transcript amplification and sequencing as universal method to test mRNA integrity and biallelic expression in mismatch repair genes. Eur J Hum Genet 2019; 27:1808-1820. [PMID: 31332305 DOI: 10.1038/s41431-019-0472-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/13/2019] [Accepted: 07/02/2019] [Indexed: 12/13/2022] Open
Abstract
In pathogenicity assessment, RNA-based analyses are important for the correct classification of variants, and require gene-specific cut-offs for allelic representation and alternative/aberrant splicing. Beside this, the diagnostic yield of RNA-based techniques capable to detect aberrant splicing or allelic loss due to intronic/regulatory variants has to be elaborated. We established a cDNA analysis for full-length transcripts (FLT) of the four DNA mismatch repair (MMR) genes to investigate the splicing pattern and transcript integrity with active/inhibited nonsense-mediated mRNA-decay (NMD). Validation was based on results from normal controls, samples with premature termination codons (PTC), samples with splice-site defects (SSD), and samples with pathogenic putative missense variants. The method was applied to patients with variants of uncertain significance (VUS) or unexplained immunohistochemical MMR deficiency. We categorized the allelic representation into biallelic (50 ± 10%) or allelic loss (≤10%), and >10% and <40% as unclear. We defined isoforms up to 10% and exon-specific exceptions as alternative splicing, set the cut-off for SSD in cDNA + P to 30-50%, and regard >10% and <30% as unclear. FLT cDNA analyses designated 16% of all putative missense variants and 12% of VUS as SSD, detected MMR-defects in 19% of the unsolved patients, and re-classified >30% of VUS. Our method allows a standardized, systematic cDNA analysis of the MMR FLTs to assess the pathogenicity mechanism of VUS on RNA level, which will gain relevance for precision medicine and gene therapy. Diagnostic accuracy will be enhanced by detecting MMR defects in hitherto unsolved patients. The data generated will help to calibrate a high-throughput NGS-based mRNA-analysis and optimize prediction programs.
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Affiliation(s)
- Monika Morak
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany. .,MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany.
| | - Kerstin Schaefer
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany
| | - Verena Steinke-Lange
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany.,MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany
| | - Udo Koehler
- MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany
| | - Susanne Keinath
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany
| | - Trisari Massdorf
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany.,MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany
| | - Brigitte Mauracher
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany
| | - Nils Rahner
- Medical Faculty, Institute of Human Genetics, Heinrich-Heine University, Düsseldorf, Germany
| | - Jessica Bailey
- Clinical Genetics, St. George's University Hospital NHS Foundation Trust, London, UK
| | | | - Tanja Haeusser
- MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany
| | - Andreas Laner
- MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany
| | - Elke Holinski-Feder
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany. .,MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany.
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11
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Shuen AY, Lanni S, Panigrahi GB, Edwards M, Yu L, Campbell BB, Mandel A, Zhang C, Zhukova N, Alharbi M, Bernstein M, Bowers DC, Carroll S, Cole KA, Constantini S, Crooks B, Dvir R, Farah R, Hijiya N, George B, Laetsch TW, Larouche V, Lindhorst S, Luiten RC, Magimairajan V, Mason G, Mason W, Mordechai O, Mushtaq N, Nicholas G, Oren M, Palma L, Pedroza LA, Ramdas J, Samuel D, Wolfe Schneider K, Seeley A, Semotiuk K, Shamvil A, Sumerauer D, Toledano H, Tomboc P, Wierman M, Van Damme A, Lee YY, Zapotocky M, Bouffet E, Durno C, Aronson M, Gallinger S, Foulkes WD, Malkin D, Tabori U, Pearson CE. Functional Repair Assay for the Diagnosis of Constitutional Mismatch Repair Deficiency From Non-Neoplastic Tissue. J Clin Oncol 2019; 37:461-470. [PMID: 30608896 DOI: 10.1200/jco.18.00474] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
PURPOSE Constitutional mismatch repair deficiency (CMMRD) is a highly penetrant cancer predisposition syndrome caused by biallelic mutations in mismatch repair (MMR) genes. As several cancer syndromes are clinically similar, accurate diagnosis is critical to cancer screening and treatment. As genetic diagnosis is confounded by 15 or more pseudogenes and variants of uncertain significance, a robust diagnostic assay is urgently needed. We sought to determine whether an assay that directly measures MMR activity could accurately diagnose CMMRD. PATIENTS AND METHODS In vitro MMR activity was quantified using a 3'-nicked G-T mismatched DNA substrate, which requires MSH2-MSH6 and MLH1-PMS2 for repair. We quantified MMR activity from 20 Epstein-Barr virus-transformed lymphoblastoid cell lines from patients with confirmed CMMRD. We also tested 20 lymphoblastoid cell lines from patients who were suspected for CMMRD. We also characterized MMR activity from patients with neurofibromatosis type 1, Li-Fraumeni syndrome, polymerase proofreading-associated cancer syndrome, and Lynch syndrome. RESULTS All CMMRD cell lines had low MMR activity (n = 20; mean, 4.14 ± 1.56%) relative to controls (n = 6; mean, 44.00 ± 8.65%; P < .001). Repair was restored by complementation with the missing protein, which confirmed MMR deficiency. All cases of patients with suspected CMMRD were accurately diagnosed. Individuals with Lynch syndrome (n = 28), neurofibromatosis type 1 (n = 5), Li-Fraumeni syndrome (n = 5), and polymerase proofreading-associated cancer syndrome (n = 3) had MMR activity that was comparable to controls. To accelerate testing, we measured MMR activity directly from fresh lymphocytes, which yielded results in 8 days. CONCLUSION On the basis of the current data set, the in vitro G-T repair assay was able to diagnose CMMRD with 100% specificity and sensitivity. Rapid diagnosis before surgery in non-neoplastic tissues could speed proper therapeutic management.
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Affiliation(s)
- Andrew Y Shuen
- 1 University of Toronto, Toronto, Ontario, Canada.,2 The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Stella Lanni
- 2 The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | - Lisa Yu
- 2 The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Brittany B Campbell
- 1 University of Toronto, Toronto, Ontario, Canada.,2 The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ariane Mandel
- 2 The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Cindy Zhang
- 2 The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nataliya Zhukova
- 1 University of Toronto, Toronto, Ontario, Canada.,2 The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Mark Bernstein
- 4 Dalhousie University Faculty of Medicine, Halifax, Nova Scotia, Canada
| | - Daniel C Bowers
- 5 University of Texas Southwestern Medical Center, Dallas, TX.,6 Children's Health, Dallas, TX
| | | | - Kristina A Cole
- 8 Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA
| | - Shlomi Constantini
- 9 Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,10 Tel Aviv University, Tel Aviv, Israel
| | - Bruce Crooks
- 4 Dalhousie University Faculty of Medicine, Halifax, Nova Scotia, Canada
| | - Rina Dvir
- 10 Tel Aviv University, Tel Aviv, Israel.,11 Schneider Children's Medical Center of Israel, Petach Tikva, Israel
| | - Roula Farah
- 12 Saint George Hospital University Medical Center, Beirut, Lebanon
| | - Nobuko Hijiya
- 13 Ann & Robert H. Lurie Children's Hospital/Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Ben George
- 14 Medical College of Wisconsin, Milwaukee, WI
| | - Theodore W Laetsch
- 5 University of Texas Southwestern Medical Center, Dallas, TX.,6 Children's Health, Dallas, TX
| | | | | | | | | | - Gary Mason
- 19 Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Warren Mason
- 1 University of Toronto, Toronto, Ontario, Canada.,20 Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | | | | | - Garth Nicholas
- 23 Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | | | - Laura Palma
- 25 McGill University Health Centre, Montréal, Quebec, Canada
| | - Luis Alberto Pedroza
- 26 Baylor College of Medicine and Texas Children's Hospital, Houston, TX.,27 Universidad San Francisco de Quito, Quito, Ecuador
| | | | | | - Kami Wolfe Schneider
- 30 Children's Hospital Colorado, Aurora, CO.,31 University of Colorado, Anschutz Medical Campus, Aurora, CO
| | | | | | | | - David Sumerauer
- 34 University Hospital Motol, Charles University, Prague, Czech Republic
| | - Helen Toledano
- 11 Schneider Children's Medical Center of Israel, Petach Tikva, Israel
| | | | | | - An Van Damme
- 36 Université Catholique de Louvain, Brussels, Belgium
| | - Yi-Yen Lee
- 37 Taipei Veterans General Hospital, Taipei, Republic of China
| | - Michal Zapotocky
- 1 University of Toronto, Toronto, Ontario, Canada.,2 The Hospital for Sick Children, Toronto, Ontario, Canada.,34 University Hospital Motol, Charles University, Prague, Czech Republic
| | - Eric Bouffet
- 1 University of Toronto, Toronto, Ontario, Canada.,2 The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Carol Durno
- 2 The Hospital for Sick Children, Toronto, Ontario, Canada.,32 Mount Sinai Hospital, Toronto, Ontario, Canada
| | | | - Steve Gallinger
- 32 Mount Sinai Hospital, Toronto, Ontario, Canada.,38 Toronto General Hospital, Toronto, Ontario, Canada
| | | | - David Malkin
- 1 University of Toronto, Toronto, Ontario, Canada.,2 The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Uri Tabori
- 1 University of Toronto, Toronto, Ontario, Canada.,2 The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Christopher E Pearson
- 1 University of Toronto, Toronto, Ontario, Canada.,2 The Hospital for Sick Children, Toronto, Ontario, Canada
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12
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Suerink M, Ripperger T, Messiaen L, Menko FH, Bourdeaut F, Colas C, Jongmans M, Goldberg Y, Nielsen M, Muleris M, van Kouwen M, Slavc I, Kratz C, Vasen HF, Brugiѐres L, Legius E, Wimmer K. Constitutional mismatch repair deficiency as a differential diagnosis of neurofibromatosis type 1: consensus guidelines for testing a child without malignancy. J Med Genet 2018; 56:53-62. [PMID: 30415209 DOI: 10.1136/jmedgenet-2018-105664] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/05/2018] [Accepted: 10/10/2018] [Indexed: 12/15/2022]
Abstract
Constitutional mismatch repair deficiency (CMMRD) is a rare childhood cancer predisposition syndrome caused by biallelic germline mutations in one of four mismatch-repair genes. Besides very high tumour risks, CMMRD phenotypes are often characterised by the presence of signs reminiscent of neurofibromatosis type 1 (NF1). Because NF1 signs may be present prior to tumour onset, CMMRD is a legitimate differential diagnosis in an otherwise healthy child suspected to have NF1/Legius syndrome without a detectable underlying NF1/SPRED1 germline mutation. However, no guidelines indicate when to counsel and test for CMMRD in this setting. Assuming that CMMRD is rare in these patients and that expected benefits of identifying CMMRD prior to tumour onset should outweigh potential harms associated with CMMRD counselling and testing in this setting, we aimed at elaborating a strategy to preselect, among children suspected to have NF1/Legius syndrome without a causative NF1/SPRED1 mutation and no overt malignancy, those children who have a higher probability of having CMMRD. At an interdisciplinary workshop, we discussed estimations of the frequency of CMMRD as a differential diagnosis of NF1 and potential benefits and harms of CMMRD counselling and testing in a healthy child with no malignancy. Preselection criteria and strategies for counselling and testing were developed and reviewed in two rounds of critical revisions. Existing diagnostic CMMRD criteria were adapted to serve as a guideline as to when to consider CMMRD as differential diagnosis of NF1/Legius syndrome. In addition, counselling and testing strategies are suggested to minimise potential harms.
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Affiliation(s)
- Manon Suerink
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Tim Ripperger
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Ludwine Messiaen
- Department of Genetics, University of Alabama, Birmingham, Alabama, USA
| | - Fred H Menko
- Family Cancer Clinic, Antoni van Leeuwenhoek Hospital and The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Franck Bourdeaut
- Département d'Oncologie Pédiatrique et d'Adolescents Jeunes Adultes, Institut Curie, Paris, France
| | - Chrystelle Colas
- Department of Genetics, Institut Curie, Paris Sciences Lettres Research University, Paris, France.,Centre de Recherche Saint-Antoine, Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Paris, France
| | - Marjolijn Jongmans
- Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands.,Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Yael Goldberg
- Recanati Genetics Institute, Beilinson Hospital, Rabin Medical Center, Petah Tikva, Israel
| | - Maartje Nielsen
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Martine Muleris
- Centre de Recherche Saint-Antoine, Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Paris, France
| | - Mariëtte van Kouwen
- Department of Gastroenterology and Hepatology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Irene Slavc
- Department of Pediatrics, Medical University Vienna, Vienna, Austria
| | - Christian Kratz
- Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | - Hans F Vasen
- Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Laurence Brugiѐres
- Children and Adolescent Oncology Department, Gustave Roussy Cancer Institute, Villejuif, France
| | - Eric Legius
- Department of Human Genetics, University Hospital Leuven and KU Leuven, Leuven, Belgium
| | - Katharina Wimmer
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
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13
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Gould GM, Grauman PV, Theilmann MR, Spurka L, Wang IE, Melroy LM, Chin RG, Hite DH, Chu CS, Maguire JR, Hogan GJ, Muzzey D. Detecting clinically actionable variants in the 3' exons of PMS2 via a reflex workflow based on equivalent hybrid capture of the gene and its pseudogene. BMC MEDICAL GENETICS 2018; 19:176. [PMID: 30268105 PMCID: PMC6162901 DOI: 10.1186/s12881-018-0691-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/20/2018] [Indexed: 12/14/2022]
Abstract
Background Hereditary cancer screening (HCS) for germline variants in the 3′ exons of PMS2, a mismatch repair gene implicated in Lynch syndrome, is technically challenging due to homology with its pseudogene PMS2CL. Sequences of PMS2 and PMS2CL are so similar that next-generation sequencing (NGS) of short fragments—common practice in multigene HCS panels—may identify the presence of a variant but fail to disambiguate whether its origin is the gene or the pseudogene. Molecular approaches utilizing longer DNA fragments, such as long-range PCR (LR-PCR), can definitively localize variants in PMS2, yet applying such testing to all samples can have logistical and economic drawbacks. Methods To address these drawbacks, we propose and characterize a reflex workflow for variant discovery in the 3′ exons of PMS2. We cataloged the natural variation in PMS2 and PMS2CL in 707 samples and designed hybrid-capture probes to enrich the gene and pseudogene with equal efficiency. For PMS2 exon 11, NGS reads were aligned, filtered using gene-specific variants, and subject to standard diploid variant calling. For PMS2 exons 12–15, the NGS reads were permissively aligned to PMS2, and variant calling was performed with the expectation of observing four alleles (i.e., tetraploid calling). In this reflex workflow, short-read NGS identifies potentially reportable variants that are then subject to disambiguation via LR-PCR-based testing. Results Applying short-read NGS screening to 299 HCS samples and cell lines demonstrated >99% analytical sensitivity and >99% analytical specificity for single-nucleotide variants (SNVs) and short insertions and deletions (indels), as well as >96% analytical sensitivity and >99% analytical specificity for copy-number variants. Importantly, 92% of samples had resolved genotypes from short-read NGS alone, with the remaining 8% requiring LR-PCR reflex. Conclusion Our reflex workflow mitigates the challenges of screening in PMS2 and serves as a guide for clinical laboratories performing multigene HCS. To facilitate future exploration and testing of PMS2 variants, we share the raw and processed LR-PCR data from commercially available cell lines, as well as variant frequencies from a diverse patient cohort. Electronic supplementary material The online version of this article (10.1186/s12881-018-0691-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Peter V Grauman
- Counsyl, 180 Kimball Way, South San Francisco, CA, 94080, USA
| | | | - Lindsay Spurka
- Counsyl, 180 Kimball Way, South San Francisco, CA, 94080, USA
| | - Irving E Wang
- Counsyl, 180 Kimball Way, South San Francisco, CA, 94080, USA
| | - Laura M Melroy
- Counsyl, 180 Kimball Way, South San Francisco, CA, 94080, USA
| | - Robert G Chin
- Counsyl, 180 Kimball Way, South San Francisco, CA, 94080, USA
| | - Dustin H Hite
- Counsyl, 180 Kimball Way, South San Francisco, CA, 94080, USA
| | - Clement S Chu
- Counsyl, 180 Kimball Way, South San Francisco, CA, 94080, USA
| | - Jared R Maguire
- Counsyl, 180 Kimball Way, South San Francisco, CA, 94080, USA
| | - Gregory J Hogan
- Counsyl, 180 Kimball Way, South San Francisco, CA, 94080, USA
| | - Dale Muzzey
- Counsyl, 180 Kimball Way, South San Francisco, CA, 94080, USA.
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14
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Bowles KR, Mancini-DiNardo D, Coffee B, Cox HC, Qian Y, Elias M, Singh N, Judkins T, Leclair B, Roa BB. Hereditary cancer testing challenges: assembling the analytical pieces to solve the patient clinical puzzle. Future Oncol 2018; 15:65-79. [PMID: 30113232 DOI: 10.2217/fon-2018-0476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Expanded genetic test utilization to guide cancer management has driven the development of larger gene panels and greater diversity in the patient population pursuing testing, resulting in increased identification of atypical or technically challenging genetic findings. To ensure appropriate patient care, it is critical that genetic tests adequately identify and characterize these findings. We describe genetic testing challenges frequently encountered by our laboratory and the methodologies we employ to improve test accuracy for the identification and characterization of atypical genetic findings. While these findings may be individually rare, 15,745 (9%) individuals tested by our laboratory for hereditary cancer risk had an atypical genetic finding, highlighting the importance of employing highly accurate and comprehensive methods in clinical genetic testing.
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Affiliation(s)
- Karla R Bowles
- Myriad Genetic Laboratories, Inc., 320 Wakara Way, Salt Lake City, UT 84108, USA
| | | | - Bradford Coffee
- Myriad Genetic Laboratories, Inc., 320 Wakara Way, Salt Lake City, UT 84108, USA
| | - Hannah C Cox
- Myriad Genetic Laboratories, Inc., 320 Wakara Way, Salt Lake City, UT 84108, USA
| | - Yaping Qian
- Myriad Genetic Laboratories, Inc., 320 Wakara Way, Salt Lake City, UT 84108, USA
| | - Maria Elias
- Myriad Genetic Laboratories, Inc., 320 Wakara Way, Salt Lake City, UT 84108, USA
| | - Nanda Singh
- Myriad Genetic Laboratories, Inc., 320 Wakara Way, Salt Lake City, UT 84108, USA
| | - Thaddeus Judkins
- Myriad Genetic Laboratories, Inc., 320 Wakara Way, Salt Lake City, UT 84108, USA
| | - Benoît Leclair
- Myriad Genetic Laboratories, Inc., 320 Wakara Way, Salt Lake City, UT 84108, USA
| | - Benjamin B Roa
- Myriad Genetic Laboratories, Inc., 320 Wakara Way, Salt Lake City, UT 84108, USA
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15
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Herman DS, Smith C, Liu C, Vaughn CP, Palaniappan S, Pritchard CC, Shirts BH. Efficient Detection of Copy Number Mutations in PMS2 Exons with a Close Homolog. J Mol Diagn 2018; 20:512-521. [PMID: 29792936 DOI: 10.1016/j.jmoldx.2018.03.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 03/23/2018] [Indexed: 01/25/2023] Open
Abstract
Detection of 3' PMS2 copy-number mutations that cause Lynch syndrome is difficult because of highly homologous pseudogenes. To improve the accuracy and efficiency of clinical screening for these mutations, we developed a new method to analyze standard capture-based, next-generation sequencing data to identify deletions and duplications in PMS2 exons 9 to 15. The approach captures sequences using PMS2 targets, maps sequences randomly among regions with equal mapping quality, counts reads aligned to homologous exons and introns, and flags read count ratios outside of empirically derived reference ranges. The method was trained on 1352 samples, including 8 known positives, and tested on 719 samples, including 17 known positives. Clinical implementation of the first version of this method detected new mutations in the training (N = 7) and test (N = 2) sets that had not been identified by our initial clinical testing pipeline. The described final method showed complete sensitivity in both sample sets and false-positive rates of 5% (training) and 7% (test), dramatically decreasing the number of cases needing additional mutation evaluation. This approach leveraged the differences between gene and pseudogene to distinguish between PMS2 and PMS2CL copy-number mutations. These methods enable efficient and sensitive Lynch syndrome screening for 3' PMS2 copy-number mutations and may be applied similarly to other genomic regions with highly homologous pseudogenes.
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Affiliation(s)
- Daniel S Herman
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Laboratory Medicine, University of Washington, Seattle, Washington.
| | - Christina Smith
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Chang Liu
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | | | - Selvi Palaniappan
- Department of Clinical Genomics, Ambry Genetics, Aliso Viejo, California
| | - Colin C Pritchard
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Brian H Shirts
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
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16
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Andrianova MA, Chetan GK, Sibin MK, Mckee T, Merkler D, Narasinga RK, Ribaux P, Blouin JL, Makrythanasis P, Seplyarskiy VB, Antonarakis SE, Nikolaev SI. Germline PMS2 and somatic POLE exonuclease mutations cause hypermutability of the leading DNA strand in biallelic mismatch repair deficiency syndrome brain tumours. J Pathol 2017; 243:331-341. [PMID: 28805995 DOI: 10.1002/path.4957] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 08/02/2017] [Accepted: 08/09/2017] [Indexed: 12/18/2022]
Abstract
Biallelic mismatch repair deficiency (bMMRD) in tumours is frequently associated with somatic mutations in the exonuclease domains of DNA polymerases POLE or POLD1, and results in a characteristic mutational profile. In this article, we describe the genetic basis of ultramutated high-grade brain tumours in the context of bMMRD. We performed exome sequencing of two second-cousin patients from a large consanguineous family of Indian origin with early onset of high-grade glioblastoma and astrocytoma. We identified a germline homozygous nonsense variant, p.R802*, in the PMS2 gene. Additionally, by genome sequencing of these tumours, we found extremely high somatic mutation rates (237/Mb and 123/Mb), as well as somatic mutations in the proofreading domain of POLE polymerase (p.P436H and p.L424V), which replicates the leading DNA strand. Most interestingly, we found, in both cancers, that the vast majority of mutations were consistent with the signature of POLE exo- , i.e. an abundance of C>A and C>T mutations, particularly in special contexts, on the leading strand. We showed that the fraction of mutations under positive selection among mutations in tumour suppressor genes is more than two-fold lower in ultramutated tumours than in other glioblastomas. Genetic analyses enabled the diagnosis of the two consanguineous childhood brain tumours as being due to a combination of PMS2 germline and POLE somatic variants, and confirmed them as bMMRD/POLE exo- disorders. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
| | - Ghati Kasturirangan Chetan
- Department of Human Genetics, National Institute of Mental Health & Neurosciences (NIMHANS), Bangalore, India
| | - Madathan Kandi Sibin
- Department of Human Genetics, National Institute of Mental Health & Neurosciences (NIMHANS), Bangalore, India
| | - Thomas Mckee
- Service of Clinical Pathology, University Hospitals of Geneva, Geneva, Switzerland
| | - Doron Merkler
- Department of Pathology and Immunology, Université de Genève (UNIGE), Geneva, Switzerland
| | - Rao Kvl Narasinga
- Department of Neuro-surgery, National Institute of Mental Health & Neurosciences (NIMHANS), Bangalore, India
| | - Pascale Ribaux
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland
| | - Jean-Louis Blouin
- Service of Genetic Medicine, Geneva University Hospitals (HUG), Geneva, Switzerland
| | - Periklis Makrythanasis
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland.,Service of Genetic Medicine, Geneva University Hospitals (HUG), Geneva, Switzerland
| | - Vladimir B Seplyarskiy
- Institute of Information Transmission Problems, Moscow, Russia.,Moscow State University, Moscow, Russia.,Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Stylianos E Antonarakis
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland.,Service of Genetic Medicine, Geneva University Hospitals (HUG), Geneva, Switzerland
| | - Sergey I Nikolaev
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland.,Service of Genetic Medicine, Geneva University Hospitals (HUG), Geneva, Switzerland
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17
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Screening for germline mutations in mismatch repair genes in patients with Lynch syndrome by next generation sequencing. Fam Cancer 2017; 17:387-394. [DOI: 10.1007/s10689-017-0043-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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18
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A molecular portrait of microsatellite instability across multiple cancers. Nat Commun 2017; 8:15180. [PMID: 28585546 PMCID: PMC5467167 DOI: 10.1038/ncomms15180] [Citation(s) in RCA: 410] [Impact Index Per Article: 58.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 03/03/2017] [Indexed: 12/30/2022] Open
Abstract
Microsatellite instability (MSI) refers to the hypermutability of short repetitive sequences in the genome caused by impaired DNA mismatch repair. Although MSI has been studied for decades, large amounts of sequencing data now available allows us to examine the molecular fingerprints of MSI in greater detail. Here, we analyse ∼8,000 exomes and ∼1,000 whole genomes of cancer patients across 23 cancer types. Our analysis reveals that the frequency of MSI events is highly variable within and across tumour types. We also identify genes in DNA repair and oncogenic pathways recurrently subject to MSI and uncover non-coding loci that frequently display MSI. Finally, we propose a highly accurate exome-based predictive model for the MSI phenotype. These results advance our understanding of the genomic drivers and consequences of MSI, and our comprehensive catalogue of tumour-type-specific MSI loci will enable panel-based MSI testing to identify patients who are likely to benefit from immunotherapy. Some cancers with DNA mismatch repair deficiency display microsatellite instability. Here the authors analyse twenty three cancer types at the exome and whole-genome level, and identify loci with recurrent microsatellite instability that could be used to identify patients who would benefit from immunotherapy.
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19
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Wimmer K, Rosenbaum T, Messiaen L. Connections between constitutional mismatch repair deficiency syndrome and neurofibromatosis type 1. Clin Genet 2017; 91:507-519. [PMID: 27779754 DOI: 10.1111/cge.12904] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/18/2016] [Accepted: 10/20/2016] [Indexed: 12/13/2022]
Abstract
Constitutional mismatch repair (MMR) deficiency (CMMRD) is a rare childhood cancer susceptibility syndrome resulting from biallelic germline loss-of-function mutations in one of the MMR genes. Individuals with CMMRD have high risk to develop a broad spectrum of malignancies and frequently display features reminiscent of neurofibromatosis type 1 (NF1). Evaluation of the clinical findings of genetically proven CMMRD patients shows that not only multiple café-au-lait macules but also any of the diagnostic features of NF1 may be present in a CMMRD patient. This phenotypic overlap may lead to misdiagnosis of CMMRD patients as having NF1, which impedes adequate management of the patients and their families. The spectrum of CMMRD-associated childhood malignancies includes high-grade glioma, acute myeloid leukaemia or rhabdomyosarcoma, also reported as associated with NF1. Reported associations between NF1 and these malignancies are to a large extent based on studies that neither proved the presence of an NF1 germline mutation nor ruled-out CMMRD in the affected. Hence, these associations are challenged by our current knowledge of the phenotypic overlap between NF1 and CMMRD and should be re-evaluated in future studies. Recent advances in the diagnostics of CMMRD should render it possible to definitely state or refute this diagnosis in these individuals.
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Affiliation(s)
- K Wimmer
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - T Rosenbaum
- Department of Pediatrics, Sana Kliniken Duisburg, Wedau Kliniken, Duisburg, Germany
| | - L Messiaen
- Medical Genomics Laboratory, Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
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20
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van der Klift HM, Mensenkamp AR, Drost M, Bik EC, Vos YJ, Gille HJJP, Redeker BEJW, Tiersma Y, Zonneveld JBM, García EG, Letteboer TGW, Olderode-Berends MJW, van Hest LP, van Os TA, Verhoef S, Wagner A, van Asperen CJ, Ten Broeke SW, Hes FJ, de Wind N, Nielsen M, Devilee P, Ligtenberg MJL, Wijnen JT, Tops CMJ. Comprehensive Mutation Analysis of PMS2 in a Large Cohort of Probands Suspected of Lynch Syndrome or Constitutional Mismatch Repair Deficiency Syndrome. Hum Mutat 2016; 37:1162-1179. [PMID: 27435373 DOI: 10.1002/humu.23052] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 07/06/2016] [Accepted: 07/07/2016] [Indexed: 01/01/2023]
Abstract
Monoallelic PMS2 germline mutations cause 5%-15% of Lynch syndrome, a midlife cancer predisposition, whereas biallelic PMS2 mutations cause approximately 60% of constitutional mismatch repair deficiency (CMMRD), a rare childhood cancer syndrome. Recently improved DNA- and RNA-based strategies are applied to overcome problematic PMS2 mutation analysis due to the presence of pseudogenes and frequent gene conversion events. Here, we determined PMS2 mutation detection yield and mutation spectrum in a nationwide cohort of 396 probands. Furthermore, we studied concordance between tumor IHC/MSI (immunohistochemistry/microsatellite instability) profile and mutation carrier state. Overall, we found 52 different pathogenic PMS2 variants explaining 121 Lynch syndrome and nine CMMRD patients. In vitro mismatch repair assays suggested pathogenicity for three missense variants. Ninety-one PMS2 mutation carriers (70%) showed isolated loss of PMS2 in their tumors, for 31 (24%) no or inconclusive IHC was available, and eight carriers (6%) showed discordant IHC (presence of PMS2 or loss of both MLH1 and PMS2). Ten cases with isolated PMS2 loss (10%; 10/97) harbored MLH1 mutations. We confirmed that recently improved mutation analysis provides a high yield of PMS2 mutations in patients with isolated loss of PMS2 expression. Application of universal tumor prescreening methods will however miss some PMS2 germline mutation carriers.
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Affiliation(s)
- Heleen M van der Klift
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands. .,Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands.
| | - Arjen R Mensenkamp
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mark Drost
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Elsa C Bik
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Yvonne J Vos
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Hans J J P Gille
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands
| | - Bert E J W Redeker
- Department of Clinical Genetics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Yvonne Tiersma
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - José B M Zonneveld
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Encarna Gómez García
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Tom G W Letteboer
- Department of Medical Genetics, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Maran J W Olderode-Berends
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Liselotte P van Hest
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands
| | - Theo A van Os
- Department of Clinical Genetics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Senno Verhoef
- Netherlands Cancer Institute, Amsterdam, The Netherlands.,Clinical Genetics Service, Saint Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, United Kingdom
| | - Anja Wagner
- Department of Clinical Genetics, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Christi J van Asperen
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Sanne W Ten Broeke
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Frederik J Hes
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Niels de Wind
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Maartje Nielsen
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Peter Devilee
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Marjolijn J L Ligtenberg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Juul T Wijnen
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands.,Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Carli M J Tops
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
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21
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PMS2 inactivation by a complex rearrangement involving an HERV retroelement and the inverted 100-kb duplicon on 7p22.1. Eur J Hum Genet 2016; 24:1598-1604. [PMID: 27329736 DOI: 10.1038/ejhg.2016.75] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/12/2016] [Accepted: 05/26/2016] [Indexed: 11/08/2022] Open
Abstract
Biallelic PMS2 mutations are responsible for more than half of all cases of constitutional mismatch repair deficiency (CMMRD), a recessively inherited childhood cancer predisposition syndrome. The mismatch repair gene PMS2 is partly embedded within one copy of an inverted 100-kb low-copy repeat (LCR) on 7p22.1. In an individual with CMMRD syndrome, PMS2 was found to be homozygously inactivated by a complex chromosomal rearrangement, which separates the 5'-part from the 3'-part of the gene. The rearrangement involves sequences of the inverted 100-kb LCR and a human endogenous retrovirus element and may be associated with an inversion that is indistinguishable from the known inversion polymorphism affecting the ~0.7-Mb sequence intervening the LCR. Its formation is best explained by a replication-based mechanism (RBM) such as fork stalling and template switching/microhomology-mediated break-induced replication (FoSTeS/MMBIR). This finding supports the hypothesis that the inverted LCR can not only facilitate the formation of the non-allelic homologous recombination-mediated inversion polymorphism but it also promotes the occurrence of more complex rearrangements that can be associated with a large inversion, as well, but are mediated by a RBM. This further suggests that among the inversion polymorphism on 7p22.1, more complex rearrangements might be hidden. Furthermore, as the locus is embedded in a common fragile site (CFS) region, this rearrangement also supports the recently raised hypothesis that CFS sequence motifs may facilitate replication-based rearrangement mechanisms.
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22
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Li J, Dai H, Feng Y, Tang J, Chen S, Tian X, Gorman E, Schmitt ES, Hansen TAA, Wang J, Plon SE, Zhang VW, Wong LJC. A Comprehensive Strategy for Accurate Mutation Detection of the Highly Homologous PMS2. J Mol Diagn 2016; 17:545-53. [PMID: 26320870 DOI: 10.1016/j.jmoldx.2015.04.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/07/2015] [Accepted: 04/29/2015] [Indexed: 10/23/2022] Open
Abstract
Germline mutations in the DNA mismatch repair gene PMS2 underlie the cancer susceptibility syndrome, Lynch syndrome. However, accurate molecular testing of PMS2 is complicated by a large number of highly homologous sequences. To establish a comprehensive approach for mutation detection of PMS2, we have designed a strategy combining targeted capture next-generation sequencing (NGS), multiplex ligation-dependent probe amplification, and long-range PCR followed by NGS to simultaneously detect point mutations and copy number changes of PMS2. Exonic deletions (E2 to E9, E5 to E9, E8, E10, E14, and E1 to E15), duplications (E11 to E12), and a nonsense mutation, p.S22*, were identified. Traditional multiplex ligation-dependent probe amplification and Sanger sequencing approaches cannot differentiate the origin of the exonic deletions in the 3' region when PMS2 and PMS2CL share identical sequences as a result of gene conversion. Our approach allows unambiguous identification of mutations in the active gene with a straightforward long-range-PCR/NGS method. Breakpoint analysis of multiple samples revealed that recurrent exon 14 deletions are mediated by homologous Alu sequences. Our comprehensive approach provides a reliable tool for accurate molecular analysis of genes containing multiple copies of highly homologous sequences and should improve PMS2 molecular analysis for patients with Lynch syndrome.
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Affiliation(s)
- Jianli Li
- Baylor Miraca Genetics Laboratories, Houston, Texas
| | | | - Yanming Feng
- Baylor Miraca Genetics Laboratories, Houston, Texas
| | - Jia Tang
- Baylor Miraca Genetics Laboratories, Houston, Texas
| | - Stella Chen
- Baylor Miraca Genetics Laboratories, Houston, Texas
| | - Xia Tian
- Baylor Miraca Genetics Laboratories, Houston, Texas
| | | | | | - Terah A A Hansen
- Central Washington Genetics Program, Yakima Valley Memorial Hospital, Yakima, Washington
| | - Jing Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Sharon E Plon
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Victor Wei Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.
| | - Lee-Jun C Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.
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23
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Clinical and Molecular Characterization of Brazilian Patients Suspected to Have Lynch Syndrome. PLoS One 2015; 10:e0139753. [PMID: 26437257 PMCID: PMC4593564 DOI: 10.1371/journal.pone.0139753] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/15/2015] [Indexed: 12/30/2022] Open
Abstract
Lynch syndrome (LS) accounts for 3–5% of all colorectal cancers (CRC) and is inherited in an autosomal dominant fashion. This syndrome is characterized by early CRC onset, high incidence of tumors in the ascending colon, excess of synchronous/metachronous tumors and extra-colonic tumors. Nowadays, LS is regarded of patients who carry deleterious germline mutations in one of the five mismatch repair genes (MMR), mostly in MLH1 and MSH2, but also in MSH6, PMS1 and PMS2. To comprehensively characterize 116 Brazilian patients suspected for LS, we assessed the frequency of germline mutations in the three minor genes MSH6, PMS1 and PMS2 in 82 patients negative for point mutations in MLH1 and MSH2. We also assessed large genomic rearrangements by MLPA for detecting copy number variations (CNVs) in MLH1, MSH2 and MSH6 generating a broad characterization of MMR genes. The complete analysis of the five MMR genes revealed 45 carriers of pathogenic mutations, including 25 in MSH2, 15 in MLH1, four in MSH6 and one in PMS2. Eleven novel pathogenic mutations (6 in MSH2, 4 in MSH6 and one in PMS2), and 11 variants of unknown significance (VUS) were found. Mutations in the MLH1 and MSH2 genes represented 89% of all mutations (40/45), whereas the three MMR genes (MSH6, PMS1 and PMS2) accounted for 11% (5/45). We also investigated the MLH1 p.Leu676Pro VUS located in the PMS2 interaction domain and our results revealed that this variant displayed no defective function in terms of cellular location and heterodimer interaction. Additionally, we assessed the tumor phenotype of a subset of patients and also the frequency of CRC and extra-colonic tumors in 2,365 individuals of the 116 families, generating the first comprehensive portrait of the genetic and clinical aspects of patients suspected of LS in a Brazilian cohort.
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24
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Nomura S, Fujimoto Y, Yamamoto N, Sato Y, Ashihara Y, Kita M, Yamaguchi J, Ishikawa Y, Ueno M, Arai M. A case of early onset rectal cancer of Lynch syndrome with a novel deleterious PMS2 mutation. Jpn J Clin Oncol 2015; 45:987-92. [PMID: 26232782 DOI: 10.1093/jjco/hyv108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 06/20/2015] [Indexed: 01/05/2023] Open
Abstract
Heterozygous deleterious mutation of the PMS2 gene is a cause of Lynch syndrome, an autosomal dominant cancer disease. However, the frequency of PMS2 mutation is rare compared with that of the other causative genes; MSH2, MLH1 and MSH6. PMS2 mutation has so far only been reported once from a Japanese facility. Detection of PMS2 mutation is relatively complicated due to the existence of 15 highly homologous pseudogenes, and its gene conversion event with the pseudogene PMS2CL. Therefore, for PMS2 mutation analysis, it is crucial to clearly distinguish PMS2 from its pseudogenes. We report here a novel deleterious 11 bp deletion mutation of exon 11 of PMS2 distinguished from PMS2CL in a 34-year-old Japanese female with rectal cancer. PMS2 mutated at c.1492del11 results in a truncated 500 amino acid protein rather than the wild-type protein of 862 amino acids. This is supported by the fact that, although there is usually concordance between MLH1 and PMS2 expression, cells were immunohistochemically positive for MLH1, whereas PMS2 could not be immunohistochemically stained using an anti-C-terminal PMS2 antibody, or effective PMS2 mRNA degradation with NMD caused by the frameshift mutation.
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Affiliation(s)
- Sachio Nomura
- Clinical Genetic Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo Department of Clinical Research, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo
| | - Yoshiya Fujimoto
- Department of Gastroenterological Surgery, Cancer Institute Hospital, Tokyo
| | - Noriko Yamamoto
- Division of Pathology, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Yuri Sato
- Clinical Genetic Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo
| | - Yuumi Ashihara
- Clinical Genetic Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo
| | - Mizuho Kita
- Clinical Genetic Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo
| | - Junya Yamaguchi
- Clinical Genetic Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo
| | - Yuichi Ishikawa
- Division of Pathology, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Masashi Ueno
- Department of Gastroenterological Surgery, Cancer Institute Hospital, Tokyo
| | - Masami Arai
- Clinical Genetic Oncology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo
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25
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Thompson B, Martins A, Spurdle A. A review of mismatch repair gene transcripts: issues for interpretation of mRNA splicing assays. Clin Genet 2014; 87:100-8. [DOI: 10.1111/cge.12450] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 06/17/2014] [Accepted: 06/24/2014] [Indexed: 12/21/2022]
Affiliation(s)
- B.A. Thompson
- Department of Genetics and Computational Biology; QIMR Berghofer Medical Research Institute; Brisbane Australia
- School of Medicine; University of Queensland; Brisbane Australia
| | - A. Martins
- Inserm U1079; University of Rouen, Institute for Research and Innovation in Biomedicine; Rouen France
| | - A.B. Spurdle
- Department of Genetics and Computational Biology; QIMR Berghofer Medical Research Institute; Brisbane Australia
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26
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Wimmer K, Kratz CP, Vasen HFA, Caron O, Colas C, Entz-Werle N, Gerdes AM, Goldberg Y, Ilencikova D, Muleris M, Duval A, Lavoine N, Ruiz-Ponte C, Slavc I, Burkhardt B, Brugieres L. Diagnostic criteria for constitutional mismatch repair deficiency syndrome: suggestions of the European consortium 'care for CMMRD' (C4CMMRD). J Med Genet 2014; 51:355-65. [PMID: 24737826 DOI: 10.1136/jmedgenet-2014-102284] [Citation(s) in RCA: 305] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Constitutional mismatch repair deficiency (CMMRD) syndrome is a distinct childhood cancer predisposition syndrome that results from biallelic germline mutations in one of the four MMR genes, MLH1, MSH2, MSH6 or PMS2. The tumour spectrum is very broad, including mainly haematological, brain and intestinal tract tumours. Patients show a variety of non-malignant features that are indicative of CMMRD. However, currently no criteria that should entail diagnostic evaluation of CMMRD exist. We present a three-point scoring system for the suspected diagnosis CMMRD in a paediatric/young adult cancer patient. Tumours highly specific for CMMRD syndrome are assigned three points, malignancies overrepresented in CMMRD two points and all other malignancies one point. According to their specificity for CMMRD and their frequency in the general population, additional features are weighted with 1-2 points. They include multiple hyperpigmented and hypopigmented skin areas, brain malformations, pilomatricomas, a second childhood malignancy, a Lynch syndrome (LS)-associated tumour in a relative and parental consanguinity. According to the scoring system, CMMRD should be suspected in any cancer patient who reaches a minimum of three points by adding the points of the malignancy and the additional features. The diagnostic steps to confirm or refute the suspected diagnosis are outlined. We expect that application of the suggested strategy for CMMRD diagnosis will increase the number of patients being identified at the time when they develop their first tumour. This will allow adjustment of the treatment modalities, offering surveillance strategies for second malignancies and appropriate counselling of the entire family.
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Affiliation(s)
- Katharina Wimmer
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - Christian P Kratz
- Department of Pediatric Hematology & Oncology, Hannover Medical School, Hannover, Germany
| | - Hans F A Vasen
- Department of Gastroenterology & Hepatology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Olivier Caron
- Department of Medical Oncology, Gustave Roussy Cancer Institute, Villejuif, France
| | - Chrystelle Colas
- Department of Genetics, Pitié Salpêtrière Hospital, AP-HP, Paris, France INSERM, UMR_S 938, CDR Saint-Antoine, Paris, France Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CDR Saint-Antoine, Paris, France
| | - Natacha Entz-Werle
- Pédiatrie Onco-Hématologie-Pédiatrie III-CHRU Hautepierre UdS-EA 3430, Strasbourg, France
| | - Anne-Marie Gerdes
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospital, Copenhagen, Denmark
| | - Yael Goldberg
- Department of Oncology, Sharret Institute, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Denisa Ilencikova
- 2nd Pediatric Department of Children University Hospital, Comenius University, Bratislava, Slovakia
| | - Martine Muleris
- INSERM, UMR_S 938, CDR Saint-Antoine, Paris, France Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CDR Saint-Antoine, Paris, France
| | - Alex Duval
- INSERM, UMR_S 938, CDR Saint-Antoine, Paris, France Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, CDR Saint-Antoine, Paris, France
| | - Noémie Lavoine
- Department of Children and Adolescents Oncology, Gustave Roussy Cancer Institute, Villejuif, France
| | - Clara Ruiz-Ponte
- Fundación Pública Galega de Medicina Xenómica (FPGMX) SERGAS, Grupo de Medicina Xenómica, IDIS, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERer), Santiago de Compostela, Spain
| | - Irene Slavc
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Brigit Burkhardt
- Department of Pediatric Hematology and Oncology, University Children's Hospital, Münster, Germany
| | - Laurence Brugieres
- Department of Children and Adolescents Oncology, Gustave Roussy Cancer Institute, Villejuif, France
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27
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Cragun D, Radford C, Dolinsky JS, Caldwell M, Chao E, Pal T. Panel-based testing for inherited colorectal cancer: a descriptive study of clinical testing performed by a US laboratory. Clin Genet 2014; 86:510-20. [PMID: 24506336 PMCID: PMC4127163 DOI: 10.1111/cge.12359] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 01/31/2014] [Accepted: 02/05/2014] [Indexed: 01/26/2023]
Abstract
Next-generation sequencing enables testing for multiple genes simultaneously (‘panel-based testing’) as opposed to sequential testing for one inherited condition at a time (‘syndrome-based testing’). This study presents results from patients who underwent hereditary colorectal cancer (CRC) panel-based testing (‘ColoNext™’). De-identified data from a clinical testing laboratory were used to calculate (1) frequencies for patient demographic, clinical, and family history variables and (2) rates of pathogenic mutations and variants of uncertain significance (VUS). The proportion of individuals with a pathogenic mutation who met national syndrome-based testing criteria was also determined. Of 586 patients, a pathogenic mutation was identified in 10.4%, while 20.1% had at least one VUS. After removing eight patients with CHEK2 mutations and 11 MUTYH heterozygotes, the percentage of patients with ‘actionable’ mutations that would clearly alter cancer screening recommendations per national guidelines decreased to 7.2%. Of 42 patients with an ‘actionable’ result, 30 (71%) clearly met established syndrome-based testing guidelines. This descriptive study is among the first to report on a large clinical series of patients undergoing panel-based testing for inherited CRC. Results are discussed in the context of benefits and concerns that have been raised about panel-based testing implementation. Conflict of interest Cristi Radford and Jill Dolinsky are full-time employees for the commercial laboratory Ambry Genetics, which performs ColoNext™ testing. Elizabeth Chao is a paid consultant for Ambry. Deborah Cragun, Meghan Caldwell, and Tuya Pal report no potential conflicts of interest. Specifically, they are not employed by Ambry, and they did not receive any financial or other incentives from Ambry.
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Affiliation(s)
- D Cragun
- H. Lee Moffitt Cancer Center, Tampa, FL, USA
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Hansen MF, Neckmann U, Lavik LAS, Vold T, Gilde B, Toft RK, Sjursen W. A massive parallel sequencing workflow for diagnostic genetic testing of mismatch repair genes. Mol Genet Genomic Med 2014; 2:186-200. [PMID: 24689082 PMCID: PMC3960061 DOI: 10.1002/mgg3.62] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 11/21/2013] [Accepted: 12/02/2013] [Indexed: 11/11/2022] Open
Abstract
The purpose of this study was to develop a massive parallel sequencing (MPS) workflow for diagnostic analysis of mismatch repair (MMR) genes using the GS Junior system (Roche). A pathogenic variant in one of four MMR genes, (MLH1, PMS2, MSH6, and MSH2), is the cause of Lynch Syndrome (LS), which mainly predispose to colorectal cancer. We used an amplicon-based sequencing method allowing specific and preferential amplification of the MMR genes including PMS2, of which several pseudogenes exist. The amplicons were pooled at different ratios to obtain coverage uniformity and maximize the throughput of a single-GS Junior run. In total, 60 previously identified and distinct variants (substitutions and indels), were sequenced by MPS and successfully detected. The heterozygote detection range was from 19% to 63% and dependent on sequence context and coverage. We were able to distinguish between false-positive and true-positive calls in homopolymeric regions by cross-sample comparison and evaluation of flow signal distributions. In addition, we filtered variants according to a predefined status, which facilitated variant annotation. Our study shows that implementation of MPS in routine diagnostics of LS can accelerate sample throughput and reduce costs without compromising sensitivity, compared to Sanger sequencing.
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Affiliation(s)
- Maren F Hansen
- Department of Laboratory Medicine, Children and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology Trondheim, Norway
| | - Ulrike Neckmann
- Department of Laboratory Medicine, Children and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology Trondheim, Norway
| | - Liss A S Lavik
- Department of Pathology and Medical Genetics, St. Olavs Hospital Trondheim, Norway
| | - Trine Vold
- Department of Pathology and Medical Genetics, St. Olavs Hospital Trondheim, Norway
| | - Bodil Gilde
- Department of Pathology and Medical Genetics, St. Olavs Hospital Trondheim, Norway
| | - Ragnhild K Toft
- Department of Laboratory Medicine, Children and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology Trondheim, Norway
| | - Wenche Sjursen
- Department of Laboratory Medicine, Children and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology Trondheim, Norway ; Department of Pathology and Medical Genetics, St. Olavs Hospital Trondheim, Norway
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Wimmer K, Wernstedt A. PMS2 gene mutational analysis: direct cDNA sequencing to circumvent pseudogene interference. Methods Mol Biol 2014; 1167:289-302. [PMID: 24823786 DOI: 10.1007/978-1-4939-0835-6_20] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The presence of highly homologous pseudocopies can compromise the mutation analysis of a gene of interest. In particular, when using PCR-based strategies, pseudogene co-amplification has to be effectively prevented. This is often achieved by using primers designed to be parental gene specific according to the reference sequence and by applying stringent PCR conditions. However, there are cases in which this approach is of limited utility. For example, it has been shown that the PMS2 gene exchanges sequences with one of its pseudogenes, named PMS2CL. This results in functional PMS2 alleles containing pseudogene-derived sequences at their 3'-end and in nonfunctional PMS2CL pseudogene alleles that contain gene-derived sequences. Hence, the paralogues cannot be distinguished according to the reference sequence. This shortcoming can be effectively circumvented by using direct cDNA sequencing. This approach is based on the selective amplification of PMS2 transcripts in two overlapping 1.6-kb RT-PCR products. In addition to avoiding pseudogene co-amplification and allele dropout, this method has also the advantage that it allows to effectively identify deletions, splice mutations, and de novo retrotransposon insertions that escape the detection of most DNA-based mutation analysis protocols.
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Affiliation(s)
- Katharina Wimmer
- Division of Human Genetics, Medical University Innsbruck, Peter-Mayr-Strasse 1, Innsbruck, 6020, Austria,
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Ingham D, Diggle CP, Berry I, Bristow CA, Hayward BE, Rahman N, Markham AF, Sheridan EG, Bonthron DT, Carr IM. Simple detection of germline microsatellite instability for diagnosis of constitutional mismatch repair cancer syndrome. Hum Mutat 2013; 34:847-52. [PMID: 23483711 DOI: 10.1002/humu.22311] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 02/28/2013] [Indexed: 11/10/2022]
Abstract
Heterozygous mutations in DNA mismatch repair (MMR) genes result in predisposition to colorectal cancer (hereditary nonpolyposis colorectal cancer or Lynch syndrome). Patients with biallelic mutations in these genes, however, present earlier, with constitutional mismatch repair deficiency cancer syndrome (CMMRD), which is characterized by a spectrum of rare childhood malignancies and café-au-lait skin patches. The hallmark of MMR deficiency, microsatellite instability (MSI), is readily detectable in tumor DNA in Lynch syndrome, but is also present in constitutional DNA of CMMRD patients. However, detection of constitutional or germline MSI (gMSI) has hitherto relied on technically difficult assays that are not routinely applicable for clinical diagnosis. Consequently, we have developed a simple high-throughput screening methodology to detect gMSI in CMMRD patients based on the presence of stutter peaks flanking a dinucleotide repeat allele when amplified from patient blood DNA samples. Using the three different microsatellite markers, the gMSI ratio was determined in a cohort of normal individuals and 10 CMMRD patients, with biallelic germline mutations in PMS2 (seven patients), MSH2 (one patient), or MSH6 (two patients). Subjects with either PMS2 or MSH2 mutations were easily identified; however, this measure was not altered in patients with CMMRD due to MSH6 mutation.
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Affiliation(s)
- Danielle Ingham
- School of Medicine, University of Leeds, Leeds, United Kingdom
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31
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Dittwald P, Gambin T, Gonzaga-Jauregui C, Carvalho CM, Lupski JR, Stankiewicz P, Gambin A. Inverted low-copy repeats and genome instability--a genome-wide analysis. Hum Mutat 2013; 34:210-20. [PMID: 22965494 PMCID: PMC3738003 DOI: 10.1002/humu.22217] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 08/30/2012] [Indexed: 01/12/2023]
Abstract
Inverse paralogous low-copy repeats (IP-LCRs) can cause genome instability by nonallelic homologous recombination (NAHR)-mediated balanced inversions. When disrupting a dosage-sensitive gene(s), balanced inversions can lead to abnormal phenotypes. We delineated the genome-wide distribution of IP-LCRs >1 kB in size with >95% sequence identity and mapped the genes, potentially intersected by an inversion, that overlap at least one of the IP-LCRs. Remarkably, our results show that 12.0% of the human genome is potentially susceptible to such inversions and 942 genes, 99 of which are on the X chromosome, are predicted to be disrupted secondary to such an inversion! In addition, IP-LCRs larger than 800 bp with at least 98% sequence identity (duplication/triplication facilitating IP-LCRs, DTIP-LCRs) were recently implicated in the formation of complex genomic rearrangements with a duplication-inverted triplication-duplication (DUP-TRP/INV-DUP) structure by a replication-based mechanism involving a template switch between such inverted repeats. We identified 1,551 DTIP-LCRs that could facilitate DUP-TRP/INV-DUP formation. Remarkably, 1,445 disease-associated genes are at risk of undergoing copy-number gain as they map to genomic intervals susceptible to the formation of DUP-TRP/INV-DUP complex rearrangements. We implicate inverted LCRs as a human genome architectural feature that could potentially be responsible for genomic instability associated with many human disease traits.
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Affiliation(s)
- Piotr Dittwald
- Institute of Informatics, University of Warsaw, Warsaw, Poland
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Warsaw, Poland
| | - Tomasz Gambin
- Institute of Computer Science, Warsaw University of Technology, Warsaw, Poland
| | | | - Claudia M.B. Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Pediatrics, Baylor College of Medicine, Houston, Texas
- Texas Children’s Hospital, Houston, Texas
| | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Anna Gambin
- Institute of Informatics, University of Warsaw, Warsaw, Poland
- Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
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Vaughn CP, Baker CL, Samowitz WS, Swensen JJ. The frequency of previously undetectable deletions involving 3' Exons of the PMS2 gene. Genes Chromosomes Cancer 2012; 52:107-12. [PMID: 23012243 DOI: 10.1002/gcc.22011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 07/11/2012] [Accepted: 08/16/2012] [Indexed: 12/30/2022] Open
Abstract
Lynch syndrome is characterized by mutations in one of four mismatch repair genes, MLH1, MSH2, MSH6, or PMS2. Clinical mutation analysis of these genes includes sequencing of exonic regions and deletion/duplication analysis. However, detection of deletions and duplications in PMS2 has previously been confined to Exons 1-11 due to gene conversion between PMS2 and the pseudogene PMS2CL in the remaining 3' exons (Exons 12-15). We have recently described an MLPA-based method that permits detection of deletions of PMS2 Exons 12-15; however, the frequency of such deletions has not yet been determined. To address this question, we tested for 3' deletions in 58 samples that were reported to be negative for PMS2 mutations using previously available methods. All samples were from individuals whose tumors exhibited loss of PMS2 immunohistochemical staining without concomitant loss of MLH1 immunostaining. We identified seven samples in this cohort with deletions in the 3' region of PMS2, including three previously reported samples with deletions of Exons 13-15 (two samples) and Exons 14-15. Also detected were deletions of Exons 12-15, Exon 13, and Exon 14 (two samples). Breakpoint analysis of the intragenic deletions suggests they occurred through Alu-mediated recombination. Our results indicate that ∼12% of samples suspected of harboring a PMS2 mutation based on immunohistochemical staining, for which mutations have not yet been identified, would benefit from testing using the new methodology.
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Affiliation(s)
- Cecily P Vaughn
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT 84108, USA
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Pritchard CC, Smith C, Salipante SJ, Lee MK, Thornton AM, Nord AS, Gulden C, Kupfer SS, Swisher EM, Bennett RL, Novetsky AP, Jarvik GP, Olopade OI, Goodfellow PJ, King MC, Tait JF, Walsh T. ColoSeq provides comprehensive lynch and polyposis syndrome mutational analysis using massively parallel sequencing. J Mol Diagn 2012; 14:357-66. [PMID: 22658618 DOI: 10.1016/j.jmoldx.2012.03.002] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 02/10/2012] [Accepted: 03/15/2012] [Indexed: 02/07/2023] Open
Abstract
Lynch syndrome (hereditary nonpolyposis colon cancer) and adenomatous polyposis syndromes frequently have overlapping clinical features. Current approaches for molecular genetic testing are often stepwise, taking a best-candidate gene approach with testing of additional genes if initial results are negative. We report a comprehensive assay called ColoSeq that detects all classes of mutations in Lynch and polyposis syndrome genes using targeted capture and massively parallel next-generation sequencing on the Illumina HiSeq2000 instrument. In blinded specimens and colon cancer cell lines with defined mutations, ColoSeq correctly identified 28/28 (100%) pathogenic mutations in MLH1, MSH2, MSH6, PMS2, EPCAM, APC, and MUTYH, including single nucleotide variants (SNVs), small insertions and deletions, and large copy number variants. There was 100% reproducibility of detection mutation between independent runs. The assay correctly identified 222 of 224 heterozygous SNVs (99.4%) in HapMap samples, demonstrating high sensitivity of calling all variants across each captured gene. Average coverage was greater than 320 reads per base pair when the maximum of 96 index samples with barcodes were pooled. In a specificity study of 19 control patients without cancer from different ethnic backgrounds, we did not find any pathogenic mutations but detected two variants of uncertain significance. ColoSeq offers a powerful, cost-effective means of genetic testing for Lynch and polyposis syndromes that eliminates the need for stepwise testing and multiple follow-up clinical visits.
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Affiliation(s)
- Colin C Pritchard
- Department of Laboratory Medicine, University of Washington, 1959 NE Pacific St, Seattle, WA 98195, USA.
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Wernstedt A, Valtorta E, Armelao F, Togni R, Girlando S, Baudis M, Heinimann K, Messiaen L, Staehli N, Zschocke J, Marra G, Wimmer K. Improved multiplex ligation-dependent probe amplification analysis identifies a deleterious PMS2 allele generated by recombination with crossover between PMS2 and PMS2CL. Genes Chromosomes Cancer 2012; 51:819-31. [PMID: 22585707 PMCID: PMC3398144 DOI: 10.1002/gcc.21966] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 04/02/2012] [Indexed: 11/08/2022] Open
Abstract
Heterozygous PMS2 germline mutations are associated with Lynch syndrome. Up to one third of these mutations are genomic deletions. Their detection is complicated by a pseudogene (PMS2CL), which--owing to extensive interparalog sequence exchange--closely resembles PMS2 downstream of exon 12. A recently redesigned multiplex ligation-dependent probe amplification (MLPA) assay identifies PMS2 copy number alterations with improved reliability when used with reference DNAs containing equal numbers of PMS2- and PMS2CL-specific sequences. We selected eight such reference samples--all publicly available--and used them with this assay to study 13 patients with PMS2-defective colorectal tumors. Three presented deleterious alterations: an Alu-mediated exon deletion; a 125-kb deletion encompassing PMS2 and four additional genes (two with tumor-suppressing functions); and a novel deleterious hybrid PMS2 allele produced by recombination with crossover between PMS2 and PMS2CL, with the breakpoint in intron 10 (the most 5' breakpoint of its kind reported thus far). We discuss mechanisms that might generate this allele in different chromosomal configurations (and their diagnostic implications) and describe an allele-specific PCR assay that facilitates its detection. Our data indicate that the redesigned PMS2 MLPA assay is a valid first-line option. In our series, it identified roughly a quarter of all PMS2 mutations.
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35
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Vaughn CP, Hart KJ, Samowitz WS, Swensen JJ. Avoidance of pseudogene interference in the detection of 3′ deletions in PMS2. Hum Mutat 2011; 32:1063-71. [DOI: 10.1002/humu.21540] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 05/06/2011] [Indexed: 11/08/2022]
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36
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Ganster C, Wernstedt A, Kehrer-Sawatzki H, Messiaen L, Schmidt K, Rahner N, Heinimann K, Fonatsch C, Zschocke J, Wimmer K. Functional PMS2 hybrid alleles containing a pseudogene-specific missense variant trace back to a single ancient intrachromosomal recombination event. Hum Mutat 2010; 31:552-60. [PMID: 20186689 DOI: 10.1002/humu.21223] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Sequence exchange between PMS2 and its pseudogene PMS2CL, embedded in an inverted duplication on chromosome 7p22, has been reported to be an ongoing process that leads to functional PMS2 hybrid alleles containing PMS2- and PMS2CL-specific sequence variants at the 5'-and the 3'-end, respectively. The frequency of PMS2 hybrid alleles, their biological significance, and the mechanisms underlying their formation are largely unknown. Here we show that overall hybrid alleles account for one-third of 384 PMS2 alleles analyzed in individuals of different ethnic backgrounds. Depending on the population, 14-60% of hybrid alleles carry PMS2CL-specific sequences in exons 13-15, the remainder only in exon 15. We show that exons 13-15 hybrid alleles, named H1 hybrid alleles, constitute different haplotypes but trace back to a single ancient intrachromosomal recombination event with crossover. Taking advantage of an ancestral sequence variant specific for all H1 alleles we developed a simple gDNA-based polymerase chain reaction (PCR) assay that can be used to identify H1-allele carriers with high sensitivity and specificity (100 and 99%, respectively). Because H1 hybrid alleles harbor missense variant p.N775S of so far unknown functional significance, we assessed the H1-carrier frequency in 164 colorectal cancer patients. So far, we found no indication that the variant plays a major role with regard to cancer susceptibility.
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Talseth-Palmer BA, McPhillips M, Groombridge C, Spigelman A, Scott RJ. MSH6 and PMS2 mutation positive Australian Lynch syndrome families: novel mutations, cancer risk and age of diagnosis of colorectal cancer. Hered Cancer Clin Pract 2010; 8:5. [PMID: 20487569 PMCID: PMC2890527 DOI: 10.1186/1897-4287-8-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 05/21/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Approximately 10% of Lynch syndrome families have a mutation in MSH6 and fewer families have a mutation in PMS2. It is assumed that the cancer incidence is the same in families with mutations in MSH6 as in families with mutations in MLH1/MSH2 but that the disease tends to occur later in life, little is known about families with PMS2 mutations. This study reports on our findings on mutation type, cancer risk and age of diagnosis in MSH6 and PMS2 families. METHODS A total of 78 participants (from 29 families) with a mutation in MSH6 and 7 participants (from 6 families) with a mutation in PMS2 were included in the current study. A database of de-identified patient information was analysed to extract all relevant information such as mutation type, cancer incidence, age of diagnosis and cancer type in this Lynch syndrome cohort. Cumulative lifetime risk was calculated utilising Kaplan-Meier survival analysis. RESULTS MSH6 and PMS2 mutations represent 10.3% and 1.9%, respectively, of the pathogenic mutations in our Australian Lynch syndrome families. We identified 26 different MSH6 and 4 different PMS2 mutations in the 35 families studied. We report 15 novel MSH6 and 1 novel PMS2 mutations. The estimated cumulative risk of CRC at age 70 years was 61% (similar in males and females) and 65% for endometrial cancer in MSH6 mutation carriers. The risk of developing CRC is different between males and females at age 50 years, which is 34% for males and 21% for females. CONCLUSION Novel MSH6 and PMS2 mutations are being reported and submitted to the current databases for identified Lynch syndrome mutations. Our data provides additional information to add to the genotype-phenotype spectrum for both MSH6 and PMS2 mutations.
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Affiliation(s)
- Bente A Talseth-Palmer
- School of Biomedical Sciences and Pharmacy, University of Newcastle, NSW 2308, Australia.
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Carr IM, Robinson JI, Dimitriou R, Markham AF, Morgan AW, Bonthron DT. Inferring relative proportions of DNA variants from sequencing electropherograms. Bioinformatics 2009; 25:3244-50. [PMID: 19819885 DOI: 10.1093/bioinformatics/btp583] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- I M Carr
- Leeds Institute of Molecular Medicine, Wellcome Trust Brenner Building, University of Leeds, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK.
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Roy S, Raskin L, Raymond VM, Thibodeau SN, Mody RJ, Gruber SB. Pediatric duodenal cancer and biallelic mismatch repair gene mutations. Pediatr Blood Cancer 2009; 53:116-20. [PMID: 19283792 DOI: 10.1002/pbc.21957] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gastrointestinal malignancies are extremely rare in the pediatric population, and duodenal cancers represent an even more unusual entity. Intestinal cancers in young adults and children have been observed to be associated with functional deficiencies of the mismatch repair (MMR) system causing a cancer-predisposition syndrome. We report the case of a 16-year-old female with duodenal adenocarcinoma and past history of medulloblastoma found to have a novel germline bialleleic truncating mutation (c.[949C>T]+[949C>T]) of the PMS2 gene.
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Affiliation(s)
- Sumita Roy
- Division of Pediatric Hematology-Oncology, Dept. of Pediatrics, University of Michigan Health System, Ann Arbor, Michigan 48109-0238, USA.
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Tops CMJ, Wijnen JT, Hes FJ. Introduction to molecular and clinical genetics of colorectal cancer syndromes. Best Pract Res Clin Gastroenterol 2009; 23:127-46. [PMID: 19414141 DOI: 10.1016/j.bpg.2009.02.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The understanding of molecular genetics in the field of gastroenterology has rapidly grown over the last two decades. In recent years many genes involved in the disorders of the gastrointestinal (GI) tract such as colorectal cancer (CRC) and inflammatory bowel disease have been identified. The elucidation of the molecular genetics of these diseases made it possible to study the high-penetrance susceptibility genes for disease-causing mutations with direct implications for relatives of affected individuals. The most immediate application of these advances is the opportunity of pre-symptomatic diagnosis in relatives of affected individuals by molecular genetic testing. In this article, the most commonly employed mutation detection procedures; the outcome and use of these tests in clinical practice are discussed. We focus on the three most common hereditary colorectal cancer syndromes (CCS): Lynch syndrome, familial adenomatous polyposis and MUTYH-associated polyposis.
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Affiliation(s)
- Carli M J Tops
- Centre for Human and Clinical Genetics, LUMC, Leiden, P.O. Box 9600, S06, 2300 RC Leiden, The Netherlands.
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41
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Constitutional mismatch repair-deficiency syndrome: have we so far seen only the tip of an iceberg? Hum Genet 2008; 124:105-22. [PMID: 18709565 DOI: 10.1007/s00439-008-0542-4] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Accepted: 08/06/2008] [Indexed: 10/21/2022]
Abstract
Heterozygous mutations in one of the mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 cause the dominant adult cancer syndrome termed Lynch syndrome or hereditary non-polyposis colorectal cancer. During the past 10 years, some 35 reports have delineated the phenotype of patients with biallelic inheritance of mutations in one of these MMR genes. The patients suffer from a condition that is characterised by the development of childhood cancers, mainly haematological malignancies and/or brain tumours, as well as early-onset colorectal cancers. Almost all patients also show signs reminiscent of neurofibromatosis type 1, mainly café au lait spots. Alluding to the underlying mechanism, this condition may be termed as "constitutional mismatch repair-deficiency (CMMR-D) syndrome". To give an overview of the current knowledge and its implications of this recessively inherited cancer syndrome we summarise here the genetic, clinical and pathological findings of the so far 78 reported patients of 46 families suffering from this syndrome.
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Senter L, Clendenning M, Sotamaa K, Hampel H, Green J, Potter JD, Lindblom A, Lagerstedt K, Thibodeau SN, Lindor NM, Young J, Winship I, Dowty JG, White DM, Hopper JL, Baglietto L, Jenkins MA, de la Chapelle A. The clinical phenotype of Lynch syndrome due to germ-line PMS2 mutations. Gastroenterology 2008; 135:419-28. [PMID: 18602922 PMCID: PMC2759321 DOI: 10.1053/j.gastro.2008.04.026] [Citation(s) in RCA: 385] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 03/31/2008] [Accepted: 04/24/2008] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Although the clinical phenotype of Lynch syndrome (also known as hereditary nonpolyposis colorectal cancer) has been well described, little is known about disease in PMS2 mutation carriers. Now that mutation detection methods can discern mutations in PMS2 from mutations in its pseudogenes, more mutation carriers have been identified. Information about the clinical significance of PMS2 mutations is crucial for appropriate counseling. Here, we report the clinical characteristics of a large series of PMS2 mutation carriers. METHODS We performed PMS2 mutation analysis using long-range polymerase chain reaction and multiplex ligation-dependent probe amplification for 99 probands diagnosed with Lynch syndrome-associated tumors showing isolated loss of PMS2 by immunohistochemistry. Penetrance was calculated using a modified segregation analysis adjusting for ascertainment. RESULTS Germ-line PMS2 mutations were detected in 62% of probands (n = 55 monoallelic; 6 biallelic). Among families with monoallelic PMS2 mutations, 65.5% met revised Bethesda guidelines. Compared with the general population, in mutation carriers, the incidence of colorectal cancer was 5.2-fold higher, and the incidence of endometrial cancer was 7.5-fold higher. In North America, this translates to a cumulative cancer risk to age 70 years of 15%-20% for colorectal cancer, 15% for endometrial cancer, and 25%-32% for any Lynch syndrome-associated cancer. No elevated risk for non-Lynch syndrome-associated cancers was observed. CONCLUSIONS PMS2 mutations contribute significantly to Lynch syndrome, but the penetrance for monoallelic mutation carriers appears to be lower than that for the other mismatch repair genes. Modified counseling and cancer surveillance guidelines for PMS2 mutation carriers are proposed.
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Affiliation(s)
- Leigha Senter
- Human Cancer Genetics Program, The Ohio State University Comprehensive Cancer Center Columbus, Ohio
| | - Mark Clendenning
- Human Cancer Genetics Program, The Ohio State University Comprehensive Cancer Center Columbus, Ohio
| | - Kaisa Sotamaa
- Human Cancer Genetics Program, The Ohio State University Comprehensive Cancer Center Columbus, Ohio
| | - Heather Hampel
- Human Cancer Genetics Program, The Ohio State University Comprehensive Cancer Center Columbus, Ohio
| | - Jane Green
- Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, St John’s, Newfoundland
| | - John D. Potter
- Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Annika Lindblom
- Karolinska Institute, Department of Molecular Medicine, Stockholm, Sweden
| | | | - Stephen N. Thibodeau
- Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Noralane M. Lindor
- Department of Medical Genetics, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Joanne Young
- Queensland Institute of Medical Research, Brisbane, Queensland, Australia
| | - Ingrid Winship
- Adult Clinical Genetics, The University of Melbourne, Victoria, Australia
| | - James G. Dowty
- Centre for MEGA Epidemiology, School of Population Health, The University of Melbourne, Victoria, Australia
| | - Darren M. White
- Centre for MEGA Epidemiology, School of Population Health, The University of Melbourne, Victoria, Australia
| | - John L. Hopper
- Centre for MEGA Epidemiology, School of Population Health, The University of Melbourne, Victoria, Australia
| | - Laura Baglietto
- Cancer Epidemiology Centre, The Cancer Council of Victoria, Melbourne, Victoria, Australia
| | - Mark A. Jenkins
- Centre for MEGA Epidemiology, School of Population Health, The University of Melbourne, Victoria, Australia
| | - Albert de la Chapelle
- Human Cancer Genetics Program, The Ohio State University Comprehensive Cancer Center Columbus, Ohio
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Genome-wide copy neutral LOH is infrequent in familial and sporadic microsatellite unstable carcinomas. Fam Cancer 2008; 7:319-30. [DOI: 10.1007/s10689-008-9194-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Accepted: 04/01/2008] [Indexed: 01/05/2023]
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Etzler J, Peyrl A, Zatkova A, Schildhaus HU, Ficek A, Merkelbach-Bruse S, Kratz C, Attarbaschi A, Hainfellner J, Yao S, Messiaen L, Slavc I, Wimmer K. RNA-based mutation analysis identifies an unusual MSH6 splicing defect and circumvents PMS2 pseudogene interference. Hum Mutat 2008; 29:299-305. [DOI: 10.1002/humu.20657] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Auclair J, Leroux D, Desseigne F, Lasset C, Saurin JC, Joly MO, Pinson S, Xu XL, Montmain G, Ruano E, Navarro C, Puisieux A, Wang Q. Novel biallelic mutations in MSH6 and PMS2 genes: gene conversion as a likely cause of PMS2 gene inactivation. Hum Mutat 2007; 28:1084-90. [PMID: 17557300 DOI: 10.1002/humu.20569] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Since the first report by our group in 1999, more than 20 unrelated biallelic mutations in DNA mismatch repair genes (MMR) have been identified. In the present report, we describe two novel cases: one carrying compound heterozygous mutations in the MSH6 gene; and the other, compound heterozygous mutations in the PMS2 gene. Interestingly, the inactivation of one PMS2 allele was likely caused by gene conversion. Although gene conversion has been suggested to be a mutation mechanism underlying PMS2 inactivation, this is the first report of its involvement in a pathogenic mutation. The clinical features of biallelic mutation carriers were similar to other previously described patients, with the presence of café-au-lait spots (CALS), early onset of brain tumors, and colorectal neoplasia. Our data provide further evidence of the existence, although rare, of a distinct recessively inherited syndrome on the basis of MMR constitutional inactivation. The identification of this syndrome should be useful for genetic counseling, especially in families with atypical hereditary nonpolyposis colon cancer (HNPCC) associated with childhood cancers, and for the clinical surveillance of these mutation carriers.
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Affiliation(s)
- Jessie Auclair
- Centre Léon Bérard, Unité d'Oncologie Moléculaire, Lyon, France
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