1
|
Singh P, Fragoza R, Blengini CS, Tran TN, Pannafino G, Al-Sweel N, Schimenti KJ, Schindler K, Alani EA, Yu H, Schimenti JC. Human MLH1/3 variants causing aneuploidy, pregnancy loss, and premature reproductive aging. Nat Commun 2021; 12:5005. [PMID: 34408140 PMCID: PMC8373927 DOI: 10.1038/s41467-021-25028-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 07/20/2021] [Indexed: 01/12/2023] Open
Abstract
Embryonic aneuploidy from mis-segregation of chromosomes during meiosis causes pregnancy loss. Proper disjunction of homologous chromosomes requires the mismatch repair (MMR) genes MLH1 and MLH3, essential in mice for fertility. Variants in these genes can increase colorectal cancer risk, yet the reproductive impacts are unclear. To determine if MLH1/3 single nucleotide polymorphisms (SNPs) in human populations could cause reproductive abnormalities, we use computational predictions, yeast two-hybrid assays, and MMR and recombination assays in yeast, selecting nine MLH1 and MLH3 variants to model in mice via genome editing. We identify seven alleles causing reproductive defects in mice including female subfertility and male infertility. Remarkably, in females these alleles cause age-dependent decreases in litter size and increased embryo resorption, likely a consequence of fewer chiasmata that increase univalents at meiotic metaphase I. Our data suggest that hypomorphic alleles of meiotic recombination genes can predispose females to increased incidence of pregnancy loss from gamete aneuploidy. Proper meiotic chromosome segregation requires mismatch repair genes MLH1 and MLH3, of which variants occur in the human population. Here, the authors use computational predictions and yeast assays to select human MLH1/3 variants for modelling in mice, observing reproductive defects from abnormal levels of crossing over.
Collapse
Affiliation(s)
- Priti Singh
- Dept of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, USA.,Preclinical Modeling Core Lab, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Robert Fragoza
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA.,Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | | | - Tina N Tran
- Dept of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, USA
| | - Gianno Pannafino
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Najla Al-Sweel
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Kerry J Schimenti
- Dept of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, USA
| | | | - Eric A Alani
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Haiyuan Yu
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA.,Department of Computational Biology, Cornell University, Ithaca, NY, USA
| | - John C Schimenti
- Dept of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, USA. .,Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
| |
Collapse
|
2
|
Dominguez-Valentin M, Plazzer JP, Sampson JR, Engel C, Aretz S, Jenkins MA, Sunde L, Bernstein I, Capella G, Balaguer F, Macrae F, Winship IM, Thomas H, Evans DG, Burn J, Greenblatt M, de Vos tot Nederveen Cappel WH, Sijmons RH, Nielsen M, Bertario L, Bonanni B, Tibiletti MG, Cavestro GM, Lindblom A, Valle AD, Lopez-Kostner F, Alvarez K, Gluck N, Katz L, Heinimann K, Vaccaro CA, Nakken S, Hovig E, Green K, Lalloo F, Hill J, Vasen HFA, Perne C, Büttner R, Görgens H, Holinski-Feder E, Morak M, Holzapfel S, Hüneburg R, von Knebel Doeberitz M, Loeffler M, Rahner N, Weitz J, Steinke-Lange V, Schmiegel W, Vangala D, Crosbie EJ, Pineda M, Navarro M, Brunet J, Moreira L, Sánchez A, Serra-Burriel M, Mints M, Kariv R, Rosner G, Piñero TA, Pavicic WH, Kalfayan P, Broeke SWT, Mecklin JP, Pylvänäinen K, Renkonen-Sinisalo L, Lepistö A, Peltomäki P, Hopper JL, Win AK, Buchanan DD, Lindor NM, Gallinger S, Marchand LL, Newcomb PA, Figueiredo JC, Thibodeau SN, Therkildsen C, Hansen TVO, Lindberg L, Rødland EA, Neffa F, Esperon P, Tjandra D, Möslein G, Seppälä TT, Møller P. No Difference in Penetrance between Truncating and Missense/Aberrant Splicing Pathogenic Variants in MLH1 and MSH2: A Prospective Lynch Syndrome Database Study. J Clin Med 2021; 10:jcm10132856. [PMID: 34203177 PMCID: PMC8269121 DOI: 10.3390/jcm10132856] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/31/2022] Open
Abstract
Background. Lynch syndrome is the most common genetic predisposition for hereditary cancer. Carriers of pathogenic changes in mismatch repair (MMR) genes have an increased risk of developing colorectal (CRC), endometrial, ovarian, urinary tract, prostate, and other cancers, depending on which gene is malfunctioning. In Lynch syndrome, differences in cancer incidence (penetrance) according to the gene involved have led to the stratification of cancer surveillance. By contrast, any differences in penetrance determined by the type of pathogenic variant remain unknown. Objective. To determine cumulative incidences of cancer in carriers of truncating and missense or aberrant splicing pathogenic variants of the MLH1 and MSH2 genes. Methods. Carriers of pathogenic variants of MLH1 (path_MLH1) and MSH2 (path_MSH2) genes filed in the Prospective Lynch Syndrome Database (PLSD) were categorized as truncating or missense/aberrant splicing according to the InSiGHT criteria for pathogenicity. Results. Among 5199 carriers, 1045 had missense or aberrant splicing variants, and 3930 had truncating variants. Prospective observation years for the two groups were 8205 and 34,141 years, respectively, after which there were no significant differences in incidences for cancer overall or for colorectal cancer or endometrial cancers separately. Conclusion. Truncating and missense or aberrant splicing pathogenic variants were associated with similar average cumulative incidences of cancer in carriers of path MLH1 and path_MSH2.
Collapse
Affiliation(s)
- Mev Dominguez-Valentin
- Department of Tumor Biology, Institute of Cancer Research, The Norwegian Radium Hospital, 0379 Oslo, Norway; (S.N.); (E.H.); (E.A.R.); (P.M.)
- European Hereditary Tumour Group (EHTG), c/o Lindsays, Caledonian Exchange 19A Canning Street, Edinburgh EH3 8HE, UK; (J.R.S.); (C.E.); (G.C.); (J.B.); (R.H.S.); (J.-P.M.); (G.M.); (T.T.S.)
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
- Correspondence:
| | - John-Paul Plazzer
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
- Department of Medicine, Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Melbourne, VIC 3050, Australia;
| | - Julian R. Sampson
- European Hereditary Tumour Group (EHTG), c/o Lindsays, Caledonian Exchange 19A Canning Street, Edinburgh EH3 8HE, UK; (J.R.S.); (C.E.); (G.C.); (J.B.); (R.H.S.); (J.-P.M.); (G.M.); (T.T.S.)
- Institute of Medical Genetics, Division of Cancer and Genetics, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
| | - Christoph Engel
- European Hereditary Tumour Group (EHTG), c/o Lindsays, Caledonian Exchange 19A Canning Street, Edinburgh EH3 8HE, UK; (J.R.S.); (C.E.); (G.C.); (J.B.); (R.H.S.); (J.-P.M.); (G.M.); (T.T.S.)
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, 04107 Leipzig, Germany;
| | - Stefan Aretz
- Institute of Human Genetics, National Center for Hereditary Tumor Syndromes, Medical Faculty, University Hospital Bonn, University of Bonn, 53127 Bonn, Germany; (S.A.); (C.P.); (S.H.)
| | - Mark A. Jenkins
- Melbourne School of Population and Global Health, Centre for Epidemiology and Biostatistics, The University of Melbourne, Parkville, VIC 3010, Australia; (M.A.J.); (J.L.H.); (A.K.W.)
| | - Lone Sunde
- Department of Clinical Genetics, Aalborg University Hospital, 9000 Aalborg, Denmark;
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark
| | - Inge Bernstein
- Department of Surgical Gastroenterology, Aalborg University Hospital, Aalborg University, 9100 Aalborg, Denmark;
- Department of Clinical Medicine, Aalborg University Hospital, Aalborg University, 9100 Aalborg, Denmark
| | - Gabriel Capella
- European Hereditary Tumour Group (EHTG), c/o Lindsays, Caledonian Exchange 19A Canning Street, Edinburgh EH3 8HE, UK; (J.R.S.); (C.E.); (G.C.); (J.B.); (R.H.S.); (J.-P.M.); (G.M.); (T.T.S.)
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
- Hereditary Cancer Program, Institut Català d’Oncologia-IDIBELL, L, Hospitalet de Llobregat, 08908 Barcelona, Spain; (M.P.); (M.N.); (J.B.)
| | - Francesc Balaguer
- Gastroenterology Department, Hospital Clínic de Barcelona, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d’Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036 Barcelona, Spain; (F.B.); (L.M.); (A.S.)
| | - Finlay Macrae
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
- Department of Medicine, Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Melbourne, VIC 3050, Australia;
| | - Ingrid M. Winship
- Department of Genomic Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC 3052, Australia;
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Huw Thomas
- Department of Surgery and Cancer, St Mark’s Hospital, Imperial College London, London HA1 3UJ, UK;
| | - Dafydd Gareth Evans
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester M13 9WL, UK; (D.G.E.); (K.G.); (F.L.)
| | - John Burn
- European Hereditary Tumour Group (EHTG), c/o Lindsays, Caledonian Exchange 19A Canning Street, Edinburgh EH3 8HE, UK; (J.R.S.); (C.E.); (G.C.); (J.B.); (R.H.S.); (J.-P.M.); (G.M.); (T.T.S.)
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Marc Greenblatt
- Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA;
| | | | - Rolf H. Sijmons
- European Hereditary Tumour Group (EHTG), c/o Lindsays, Caledonian Exchange 19A Canning Street, Edinburgh EH3 8HE, UK; (J.R.S.); (C.E.); (G.C.); (J.B.); (R.H.S.); (J.-P.M.); (G.M.); (T.T.S.)
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
- Department of Genetics, University Medical Center Groningen, University of Groningen, 9713GZ Groningen, The Netherlands
| | - Maartje Nielsen
- Department of Clinical Genetics, Leids Universitair Medisch Centrum, 2300RC Leiden, The Netherlands; (M.N.); (S.W.t.B.)
| | - Lucio Bertario
- Division of Cancer Prevention and Genetics, IEO, European Institute of Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, IRCCS, 20141 Milan, Italy;
| | - Bernardo Bonanni
- Division of Cancer Prevention and Genetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy;
| | - Maria Grazia Tibiletti
- Ospedale di Circolo ASST Settelaghi, Centro di Ricerca Tumori Eredo-Familiari, Università dell’Insubria, 21100 Varese, Italy;
| | - Giulia Martina Cavestro
- Gastroenterology and Gastrointestinal Endoscopy Unit, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, 20132 Milan, Italy;
| | - Annika Lindblom
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden;
| | - Adriana Della Valle
- Grupo Colaborativo Uruguayo, Investigación de Afecciones Oncológicas Hereditarias (GCU), Hospital Fuerzas Armadas, Montevideo 11600, Uruguay; (A.D.V.); (F.N.); (P.E.)
| | - Francisco Lopez-Kostner
- Programa Cáncer Heredo Familiar, Clínica Universidad de los Andes, Santiago 7550000, Chile; (F.L.-K.); (K.A.)
| | - Karin Alvarez
- Programa Cáncer Heredo Familiar, Clínica Universidad de los Andes, Santiago 7550000, Chile; (F.L.-K.); (K.A.)
| | - Nathan Gluck
- Department of Gastroenterology, Sackler Faculty of Medicine, Tel-Aviv Sourasky Medical Center, Tel-Aviv University, Tel-Aviv 64259, Israel; (N.G.); (R.K.); (G.R.)
| | - Lior Katz
- The Department of Gastroenterology, Gastro-Oncology Unit, High Risk and GI Cancer Prevention Clinic, Sheba Medical Center, Sheba 91120, Israel;
| | - Karl Heinimann
- Medical Genetics, Institute for Medical Genetics and Pathology, University Hospital Basel, 4031 Basel, Switzerland;
| | - Carlos A. Vaccaro
- Hereditary Cancer Program (PROCANHE), Hospital Italiano de Buenos Aires, Buenos Aires C1199ABB, Argentina; (C.A.V.); (T.A.P.); (W.H.P.); (P.K.)
- Instituto de Medicina Traslacional e Ingenieria Biomedica (IMTIB), CONICET IU, Hospital Italiano de Buenos Aires, Buenos Aires C1199ABB, Argentina
| | - Sigve Nakken
- Department of Tumor Biology, Institute of Cancer Research, The Norwegian Radium Hospital, 0379 Oslo, Norway; (S.N.); (E.H.); (E.A.R.); (P.M.)
- Centre for Cancer Cell Reprogramming (CanCell), Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 4950 Oslo, Norway
| | - Eivind Hovig
- Department of Tumor Biology, Institute of Cancer Research, The Norwegian Radium Hospital, 0379 Oslo, Norway; (S.N.); (E.H.); (E.A.R.); (P.M.)
- Department of Informatics, Centre for Bioinformatics, University of Oslo, 0316 Oslo, Norway
| | - Kate Green
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester M13 9WL, UK; (D.G.E.); (K.G.); (F.L.)
| | - Fiona Lalloo
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Manchester M13 9WL, UK; (D.G.E.); (K.G.); (F.L.)
| | - James Hill
- Department of Surgery, Central Manchester University Hospitals NHS, Foundation Trust, University of Manchester, London M13 9WL, UK;
| | - Hans F. A. Vasen
- Department of Gastroenterology and Hepatology, Leiden University Medical Centre, 2333 Leiden, The Netherlands;
| | - Claudia Perne
- Institute of Human Genetics, National Center for Hereditary Tumor Syndromes, Medical Faculty, University Hospital Bonn, University of Bonn, 53127 Bonn, Germany; (S.A.); (C.P.); (S.H.)
| | - Reinhard Büttner
- Institute of Pathology, University of Cologne, 50937 Cologne, Germany;
| | - Heike Görgens
- Department of Surgery, Technische Universität Dresden, 01062 Dresden, Germany; (H.G.); (J.W.)
| | - Elke Holinski-Feder
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
- Campus Innenstadt, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, 80336 Munich, Germany; (M.M.); (V.S.-L.)
- Center of Medical Genetics, 80335 Munich, Germany
| | - Monika Morak
- Campus Innenstadt, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, 80336 Munich, Germany; (M.M.); (V.S.-L.)
- Center of Medical Genetics, 80335 Munich, Germany
| | - Stefanie Holzapfel
- Institute of Human Genetics, National Center for Hereditary Tumor Syndromes, Medical Faculty, University Hospital Bonn, University of Bonn, 53127 Bonn, Germany; (S.A.); (C.P.); (S.H.)
| | - Robert Hüneburg
- Department of Internal Medicine, University Hospital Bonn, 53127 Bonn, Germany;
| | - Magnus von Knebel Doeberitz
- Department of Applied Tumour Biology, Institute of Pathology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
- Cooperation Unit Applied Tumour Biology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Markus Loeffler
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, 04107 Leipzig, Germany;
| | - Nils Rahner
- Medical School, Institute of Human Genetics, Heinrich-Heine-University, 40225 Dusseldorf, Germany;
| | - Jürgen Weitz
- Department of Surgery, Technische Universität Dresden, 01062 Dresden, Germany; (H.G.); (J.W.)
| | - Verena Steinke-Lange
- Campus Innenstadt, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, 80336 Munich, Germany; (M.M.); (V.S.-L.)
- Center of Medical Genetics, 80335 Munich, Germany
| | - Wolff Schmiegel
- Department of Medicine, Knappschaftskrankenhaus, Ruhr-University Bochum, D-44789 Bochum, Germany; (W.S.); (D.V.)
| | - Deepak Vangala
- Department of Medicine, Knappschaftskrankenhaus, Ruhr-University Bochum, D-44789 Bochum, Germany; (W.S.); (D.V.)
| | - Emma J. Crosbie
- Gynaecological Oncology Research Group, Manchester University NHS Foundation Trust, Manchester, UK and Division of Cancer Sciences, University of Manchester, Manchester M20 4GJ, UK;
| | - Marta Pineda
- Hereditary Cancer Program, Institut Català d’Oncologia-IDIBELL, L, Hospitalet de Llobregat, 08908 Barcelona, Spain; (M.P.); (M.N.); (J.B.)
| | - Matilde Navarro
- Hereditary Cancer Program, Institut Català d’Oncologia-IDIBELL, L, Hospitalet de Llobregat, 08908 Barcelona, Spain; (M.P.); (M.N.); (J.B.)
| | - Joan Brunet
- Hereditary Cancer Program, Institut Català d’Oncologia-IDIBELL, L, Hospitalet de Llobregat, 08908 Barcelona, Spain; (M.P.); (M.N.); (J.B.)
| | - Leticia Moreira
- Gastroenterology Department, Hospital Clínic de Barcelona, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d’Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036 Barcelona, Spain; (F.B.); (L.M.); (A.S.)
| | - Ariadna Sánchez
- Gastroenterology Department, Hospital Clínic de Barcelona, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d’Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036 Barcelona, Spain; (F.B.); (L.M.); (A.S.)
| | - Miquel Serra-Burriel
- Centre de Recerca en Economia i Salut (CRES-UPF), Universitat de Barcelona, 08002 Barcelona, Spain;
| | - Miriam Mints
- Division of Obstetrics and Gyneacology, Department of Women’s and Children’s Health, Karolinska Institutet, Karolinska University Hospital, Solna, 171 77 Stockholm, Sweden;
| | - Revital Kariv
- Department of Gastroenterology, Sackler Faculty of Medicine, Tel-Aviv Sourasky Medical Center, Tel-Aviv University, Tel-Aviv 64259, Israel; (N.G.); (R.K.); (G.R.)
| | - Guy Rosner
- Department of Gastroenterology, Sackler Faculty of Medicine, Tel-Aviv Sourasky Medical Center, Tel-Aviv University, Tel-Aviv 64259, Israel; (N.G.); (R.K.); (G.R.)
| | - Tamara Alejandra Piñero
- Hereditary Cancer Program (PROCANHE), Hospital Italiano de Buenos Aires, Buenos Aires C1199ABB, Argentina; (C.A.V.); (T.A.P.); (W.H.P.); (P.K.)
- Instituto de Medicina Traslacional e Ingenieria Biomedica (IMTIB), CONICET IU, Hospital Italiano de Buenos Aires, Buenos Aires C1199ABB, Argentina
| | - Walter Hernán Pavicic
- Hereditary Cancer Program (PROCANHE), Hospital Italiano de Buenos Aires, Buenos Aires C1199ABB, Argentina; (C.A.V.); (T.A.P.); (W.H.P.); (P.K.)
- Instituto de Medicina Traslacional e Ingenieria Biomedica (IMTIB), CONICET IU, Hospital Italiano de Buenos Aires, Buenos Aires C1199ABB, Argentina
| | - Pablo Kalfayan
- Hereditary Cancer Program (PROCANHE), Hospital Italiano de Buenos Aires, Buenos Aires C1199ABB, Argentina; (C.A.V.); (T.A.P.); (W.H.P.); (P.K.)
| | - Sanne W. ten Broeke
- Department of Clinical Genetics, Leids Universitair Medisch Centrum, 2300RC Leiden, The Netherlands; (M.N.); (S.W.t.B.)
| | - Jukka-Pekka Mecklin
- European Hereditary Tumour Group (EHTG), c/o Lindsays, Caledonian Exchange 19A Canning Street, Edinburgh EH3 8HE, UK; (J.R.S.); (C.E.); (G.C.); (J.B.); (R.H.S.); (J.-P.M.); (G.M.); (T.T.S.)
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
- Departments of Surgery, Central Finland Hospital Nova, University of Jyväskylä, 40620 Jyväskylä, Finland
| | - Kirsi Pylvänäinen
- Department of Education and Science, Sport and Health Sciences, Central Finland Hospital Nova, University of Jyväskylä, FI-40014 Jyväskylä, Finland;
| | - Laura Renkonen-Sinisalo
- Applied Tumour Genomics Research Program, University of Helsinki, 00014 Helsinki, Finland; (L.R.-S.); (A.L.)
- Department of Gastrointestinal Surgery, Helsinki University Central Hospital, University of Helsinki, 00280 Helsinki, Finland
| | - Anna Lepistö
- Applied Tumour Genomics Research Program, University of Helsinki, 00014 Helsinki, Finland; (L.R.-S.); (A.L.)
- Department of Gastrointestinal Surgery, Helsinki University Central Hospital, University of Helsinki, 00280 Helsinki, Finland
| | - Päivi Peltomäki
- Department of Medical and Clinical Genetics, University of Helsinki, 00014 Helsinki, Finland;
| | - John L. Hopper
- Melbourne School of Population and Global Health, Centre for Epidemiology and Biostatistics, The University of Melbourne, Parkville, VIC 3010, Australia; (M.A.J.); (J.L.H.); (A.K.W.)
| | - Aung Ko Win
- Melbourne School of Population and Global Health, Centre for Epidemiology and Biostatistics, The University of Melbourne, Parkville, VIC 3010, Australia; (M.A.J.); (J.L.H.); (A.K.W.)
| | - Daniel D. Buchanan
- Centre for Cancer Research, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, VIC 3010, Australia;
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, VIC 3010, Australia
- Genomic Medicine and Family Cancer Clinic, Royal Melbourne Hospital, Parkville, VIC 3010, Australia
| | - Noralane M. Lindor
- Department of Health Science Research, Mayo Clinic Arizona, Phoenix, AZ 85054, USA;
| | - Steven Gallinger
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada;
| | | | - Polly A. Newcomb
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA;
| | | | - Stephen N. Thibodeau
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA;
| | - Christina Therkildsen
- The Danish HNPCC Register, Clinical Research Centre, Copenhagen University Hospital, 2560 Hvidovre, Denmark;
| | - Thomas V. O. Hansen
- Department of Clinical Genetics, Rigshospitalet, Copenhagen University Hospital, 2100 Copenhagen, Denmark;
| | - Lars Lindberg
- Gastro Unit, Copenhagen University Hospital, 2560 Hvidovre, Denmark;
| | - Einar Andreas Rødland
- Department of Tumor Biology, Institute of Cancer Research, The Norwegian Radium Hospital, 0379 Oslo, Norway; (S.N.); (E.H.); (E.A.R.); (P.M.)
| | - Florencia Neffa
- Grupo Colaborativo Uruguayo, Investigación de Afecciones Oncológicas Hereditarias (GCU), Hospital Fuerzas Armadas, Montevideo 11600, Uruguay; (A.D.V.); (F.N.); (P.E.)
| | - Patricia Esperon
- Grupo Colaborativo Uruguayo, Investigación de Afecciones Oncológicas Hereditarias (GCU), Hospital Fuerzas Armadas, Montevideo 11600, Uruguay; (A.D.V.); (F.N.); (P.E.)
| | - Douglas Tjandra
- Department of Medicine, Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Melbourne, VIC 3050, Australia;
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Gabriela Möslein
- European Hereditary Tumour Group (EHTG), c/o Lindsays, Caledonian Exchange 19A Canning Street, Edinburgh EH3 8HE, UK; (J.R.S.); (C.E.); (G.C.); (J.B.); (R.H.S.); (J.-P.M.); (G.M.); (T.T.S.)
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
- Surgical Center for Hereditary Tumors, Ev. Bethesda Khs Duisburg, University Witten-Herdecke, 58448 Herdecke, Germany
| | - Toni T. Seppälä
- European Hereditary Tumour Group (EHTG), c/o Lindsays, Caledonian Exchange 19A Canning Street, Edinburgh EH3 8HE, UK; (J.R.S.); (C.E.); (G.C.); (J.B.); (R.H.S.); (J.-P.M.); (G.M.); (T.T.S.)
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
- Department of Gastrointestinal Surgery, Helsinki University Central Hospital, University of Helsinki, 00280 Helsinki, Finland
- Department of Surgical Oncology, Johns Hopkins Hospital, Baltimore, MA 21287, USA
| | - Pål Møller
- Department of Tumor Biology, Institute of Cancer Research, The Norwegian Radium Hospital, 0379 Oslo, Norway; (S.N.); (E.H.); (E.A.R.); (P.M.)
- European Hereditary Tumour Group (EHTG), c/o Lindsays, Caledonian Exchange 19A Canning Street, Edinburgh EH3 8HE, UK; (J.R.S.); (C.E.); (G.C.); (J.B.); (R.H.S.); (J.-P.M.); (G.M.); (T.T.S.)
- The International Society for Gastrointestinal Hereditary Tumours (InSiGHT), The Polyposis Registry, St Mark’s Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK; (J.-P.P.); (F.M.); (E.H.-F.)
| |
Collapse
|
3
|
Houlleberghs H, Dekker M, Lusseveld J, Pieters W, van Ravesteyn T, Verhoef S, Hofstra RMW, Te Riele H. Three-step site-directed mutagenesis screen identifies pathogenic MLH1 variants associated with Lynch syndrome. J Med Genet 2019; 57:308-315. [PMID: 31784484 DOI: 10.1136/jmedgenet-2019-106520] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 10/12/2019] [Accepted: 10/16/2019] [Indexed: 12/30/2022]
Abstract
BACKGROUND Inactivating mutations in the MLH1 DNA mismatch repair (MMR) gene underlie 42% of Lynch syndrome (LS) cases. LS is a cancer predisposition causing early onset colorectal and endometrial cancer. Nonsense and frameshift alterations unambiguously cause LS. The phenotype of missense mutations that only alter a single amino acid is often unclear. These variants of uncertain significance (VUS) hinder LS diagnosis and family screening and therefore functional tests are urgently needed. We developed a functional test for MLH1 VUS termed 'oligonucleotide-directed mutation screening' (ODMS). METHODS The MLH1 variant was introduced by oligonucleotide-directed gene modification in mouse embryonic stem cells that were subsequently exposed to the guanine analogue 6-thioguanine to determine whether the variant abrogated MMR. RESUTS In a proof-of-principle analysis, we demonstrate that ODMS can distinguish pathogenic and non-pathogenic MLH1 variants with a sensitivity of >95% and a specificity of >91%. We subsequently applied the screen to 51 MLH1 VUS and identified 31 pathogenic variants. CONCLUSION ODMS is a reliable tool to identify pathogenic MLH1 variants. Implementation in clinical diagnostics will improve clinical care of patients with suspected LS and their relatives.
Collapse
Affiliation(s)
- Hellen Houlleberghs
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Marleen Dekker
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Jarnick Lusseveld
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Wietske Pieters
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Thomas van Ravesteyn
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Senno Verhoef
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Robert M W Hofstra
- Department of Clinical Genetics, Erasmus MC, Erasmus University Rotterdam, Rotterdam, The Netherlands
| | - Hein Te Riele
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| |
Collapse
|
4
|
Abildgaard AB, Stein A, Nielsen SV, Schultz-Knudsen K, Papaleo E, Shrikhande A, Hoffmann ER, Bernstein I, Gerdes AM, Takahashi M, Ishioka C, Lindorff-Larsen K, Hartmann-Petersen R. Computational and cellular studies reveal structural destabilization and degradation of MLH1 variants in Lynch syndrome. eLife 2019; 8:e49138. [PMID: 31697235 PMCID: PMC6837844 DOI: 10.7554/elife.49138] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 10/23/2019] [Indexed: 12/13/2022] Open
Abstract
Defective mismatch repair leads to increased mutation rates, and germline loss-of-function variants in the repair component MLH1 cause the hereditary cancer predisposition disorder known as Lynch syndrome. Early diagnosis is important, but complicated by many variants being of unknown significance. Here we show that a majority of the disease-linked MLH1 variants we studied are present at reduced cellular levels. We show that destabilized MLH1 variants are targeted for chaperone-assisted proteasomal degradation, resulting also in degradation of co-factors PMS1 and PMS2. In silico saturation mutagenesis and computational predictions of thermodynamic stability of MLH1 missense variants revealed a correlation between structural destabilization, reduced steady-state levels and loss-of-function. Thus, we suggest that loss of stability and cellular degradation is an important mechanism underlying many MLH1 variants in Lynch syndrome. Combined with analyses of conservation, the thermodynamic stability predictions separate disease-linked from benign MLH1 variants, and therefore hold potential for Lynch syndrome diagnostics.
Collapse
Affiliation(s)
- Amanda B Abildgaard
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Amelie Stein
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Sofie V Nielsen
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Katrine Schultz-Knudsen
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Elena Papaleo
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Amruta Shrikhande
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular MedicineUniversity of CopenhagenCopenhagenDenmark
| | - Eva R Hoffmann
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular MedicineUniversity of CopenhagenCopenhagenDenmark
| | - Inge Bernstein
- Department of Surgical GastroenterologyAalborg University HospitalAalborgDenmark
| | | | - Masanobu Takahashi
- Department of Medical OncologyTohoku University Hospital, Tohoku UniversitySendaiJapan
| | - Chikashi Ishioka
- Department of Medical OncologyTohoku University Hospital, Tohoku UniversitySendaiJapan
| | - Kresten Lindorff-Larsen
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Rasmus Hartmann-Petersen
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| |
Collapse
|
5
|
Rath A, Mishra A, Ferreira VD, Hu C, Omerza G, Kelly K, Hesse A, Reddi HV, Grady JP, Heinen CD. Functional interrogation of Lynch syndrome-associated MSH2 missense variants via CRISPR-Cas9 gene editing in human embryonic stem cells. Hum Mutat 2019; 40:2044-2056. [PMID: 31237724 DOI: 10.1002/humu.23848] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 05/08/2019] [Accepted: 06/19/2019] [Indexed: 12/18/2022]
Abstract
Lynch syndrome (LS) predisposes patients to cancer and is caused by germline mutations in the DNA mismatch repair (MMR) genes. Identifying the deleterious mutation, such as a frameshift or nonsense mutation, is important for confirming an LS diagnosis. However, discovery of a missense variant is often inconclusive. The effects of these variants of uncertain significance (VUS) on disease pathogenesis are unclear, though understanding their impact on protein function can help determine their significance. Laboratory functional studies performed to date have been limited by their artificial nature. We report here an in-cellulo functional assay in which we engineered site-specific MSH2 VUS using clustered regularly interspaced short palindromic repeats-Cas9 gene editing in human embryonic stem cells. This approach introduces the variant into the endogenous MSH2 loci, while simultaneously eliminating the wild-type gene. We characterized the impact of the variants on cellular MMR functions including DNA damage response signaling and the repair of DNA microsatellites. We classified the MMR functional capability of eight of 10 VUS providing valuable information for determining their likelihood of being bona fide pathogenic LS variants. This human cell-based assay system for functional testing of MMR gene VUS will facilitate the identification of high-risk LS patients.
Collapse
Affiliation(s)
- Abhijit Rath
- Center for Molecular Oncology and Institute for Systems Genomics, UConn Health, Farmington, Connecticut
| | - Akriti Mishra
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut
| | | | - Chaoran Hu
- Department of Statistics, University of Connecticut, Storrs, Connecticut.,Connecticut Institute for Clinical and Translational Science, UConn Health, Farmington, Connecticut
| | - Gregory Omerza
- Clinical Genomics Laboratory, The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut
| | - Kevin Kelly
- Clinical Genomics Laboratory, The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut
| | - Andrew Hesse
- Clinical Genomics Laboratory, The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut
| | - Honey V Reddi
- Clinical Genomics Laboratory, The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut
| | - James P Grady
- Connecticut Institute for Clinical and Translational Science, UConn Health, Farmington, Connecticut
| | - Christopher D Heinen
- Center for Molecular Oncology and Institute for Systems Genomics, UConn Health, Farmington, Connecticut
| |
Collapse
|
6
|
Kašubová I, Kalman M, Jašek K, Burjanivová T, Malicherová B, Vaňochová A, Meršaková S, Lasabová Z, Plank L. Stratification of patients with colorectal cancer without the recorded family history. Oncol Lett 2019; 17:3649-3656. [PMID: 30881489 PMCID: PMC6403522 DOI: 10.3892/ol.2019.10018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 12/20/2018] [Indexed: 12/28/2022] Open
Abstract
Colorectal cancer (CRC) is a multifactorial disease and one of the most malignant tumours. In addition to the sporadic form, familial occurrences, particularly hereditary non-polyposis CRC-Lynch syndrome (LS)-are often observed. LS is caused by a germline mutation in mismatch repair (MMR) genes, whose task it is to correct errors in the DNA structure that result from its replication. The aim of the present study was to stratify CRC patients using molecular diagnostics and next generation sequencing, according to the chosen criteria [positive for microsatellite instability (MSI) and negative for a BRAF mutation and MutL homolog 1 (MLH1) methylation], and subsequently to detect pathological germline mutations in MMR genes in Slovak patients. To exclude patients with MSI from further testing, the present study detected the BRAF V600E mutation and examined MLH1 methylation status. From the 300 CRC patients, 37 cases with MSI were identified. In the MSI-positive samples, 13 cases of BRAF V600E mutation were recorded. In 24 BRAF-negative patients, 11 cases of epigenetic methylation of MLH1 and 12 cases without MLH1 methylation suspected for LS were detected, and it was not possible to analyse the methylation phenotype of 1 sample. Thus, the present study reports the novel deletion of four nucleotides, 1627_1630del AAAG (Glu544Lysfs*26) in MSH6, probably associated with LS. A second case with a nonsense mutation in MSH was also detected, namely MMR_c.1030C>T (p.Q344X).
Collapse
Affiliation(s)
- Ivana Kašubová
- Division of Oncology, Commenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Biomedical Center Martin, SK-03601 Martin, Slovakia
| | - Michal Kalman
- Department of Pathological Anatomy, Jessenius Faculty of Medicine in Martin and University Hospital in Martin, SK-03659 Martin, Slovakia
| | - Karin Jašek
- Division of Oncology, Commenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Biomedical Center Martin, SK-03601 Martin, Slovakia
| | - Tatiana Burjanivová
- Division of Oncology, Commenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Biomedical Center Martin, SK-03601 Martin, Slovakia
| | - Bibiana Malicherová
- Division of Oncology, Commenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Biomedical Center Martin, SK-03601 Martin, Slovakia
| | - Andrea Vaňochová
- Department of Molecular Biology, Jessenius Faculty of Medicine in Martin, SK-03601 Martin, Slovakia
| | - Sandra Meršaková
- Division of Oncology, Commenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Biomedical Center Martin, SK-03601 Martin, Slovakia
| | - Zora Lasabová
- Division of Oncology, Commenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Biomedical Center Martin, SK-03601 Martin, Slovakia.,Department of Molecular Biology, Jessenius Faculty of Medicine in Martin, SK-03601 Martin, Slovakia
| | - Lukáš Plank
- Department of Pathological Anatomy, Jessenius Faculty of Medicine in Martin and University Hospital in Martin, SK-03659 Martin, Slovakia
| |
Collapse
|
7
|
Natarajan P, Gold NB, Bick AG, McLaughlin H, Kraft P, Rehm HL, Peloso GM, Wilson JG, Correa A, Seidman JG, Seidman CE, Kathiresan S, Green RC. Aggregate penetrance of genomic variants for actionable disorders in European and African Americans. Sci Transl Med 2017; 8:364ra151. [PMID: 27831900 DOI: 10.1126/scitranslmed.aag2367] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 09/30/2016] [Indexed: 12/21/2022]
Abstract
In populations that have not been selected for family history of disease, it is unclear how commonly pathogenic variants (PVs) in disease-associated genes for rare Mendelian conditions are found and how often they are associated with clinical features of these conditions. We conducted independent, prospective analyses of participants in two community-based epidemiological studies to test the hypothesis that persons carrying PVs in any of 56 genes that lead to 24 dominantly inherited, actionable conditions are more likely to exhibit the clinical features of the corresponding diseases than those without PVs. Among 462 European American Framingham Heart Study (FHS) and 3223 African-American Jackson Heart Study (JHS) participants who were exome-sequenced, we identified and classified 642 and 4429 unique variants, respectively, in these 56 genes while blinded to clinical data. In the same participants, we ascertained related clinical features from the participants' clinical history of cancer and most recent echocardiograms, electrocardiograms, and lipid measurements, without knowledge of variant classification. PVs were found in 5 FHS (1.1%) and 31 JHS (1.0%) participants. Carriers of PVs were more likely than expected, on the basis of incidence in noncarriers, to have related clinical features in both FHS (80.0% versus 12.4%) and JHS (26.9% versus 5.4%), yielding standardized incidence ratios of 6.4 [95% confidence interval (CI), 1.7 to 16.5; P = 7 × 10-4) in FHS and 4.7 (95% CI, 1.9 to 9.7; P = 3 × 10-4) in JHS. Individuals unselected for family history who carry PVs in 56 genes for actionable conditions have an increased aggregated risk of developing clinical features associated with the corresponding diseases.
Collapse
Affiliation(s)
- Pradeep Natarajan
- Center for Human Genetic Research, Cardiovascular Research Center, and Cardiology Division, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Nina B Gold
- Harvard Medical School, Boston, MA 02115, USA.,Boston Children's Hospital, Boston, MA 02115, USA
| | - Alexander G Bick
- Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Heather McLaughlin
- Harvard Medical School, Boston, MA 02115, USA.,Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA.,Partners HealthCare Personalized Medicine, Boston, MA 02115, USA
| | - Peter Kraft
- Departments of Epidemiology and Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Heidi L Rehm
- Harvard Medical School, Boston, MA 02115, USA.,Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA.,Partners HealthCare Personalized Medicine, Boston, MA 02115, USA
| | - Gina M Peloso
- Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - James G Wilson
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Adolfo Correa
- Departments of Pediatrics and Medicine, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Jonathan G Seidman
- Harvard Medical School, Boston, MA 02115, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Christine E Seidman
- Harvard Medical School, Boston, MA 02115, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.,Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.,Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Sekar Kathiresan
- Center for Human Genetic Research, Cardiovascular Research Center, and Cardiology Division, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Robert C Green
- Harvard Medical School, Boston, MA 02115, USA. .,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Partners HealthCare Personalized Medicine, Boston, MA 02115, USA.,Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| |
Collapse
|
8
|
Yamaguchi-Kabata Y, Yasuda J, Tanabe O, Suzuki Y, Kawame H, Fuse N, Nagasaki M, Kawai Y, Kojima K, Katsuoka F, Saito S, Danjoh I, Motoike IN, Yamashita R, Koshiba S, Saigusa D, Tamiya G, Kure S, Yaegashi N, Kawaguchi Y, Nagami F, Kuriyama S, Sugawara J, Minegishi N, Hozawa A, Ogishima S, Kiyomoto H, Takai-Igarashi T, Kinoshita K, Yamamoto M; ToMMo Study Group. Evaluation of reported pathogenic variants and their frequencies in a Japanese population based on a whole-genome reference panel of 2049 individuals. J Hum Genet 2018; 63:213-30. [PMID: 29192238 DOI: 10.1038/s10038-017-0347-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/25/2017] [Accepted: 08/29/2017] [Indexed: 01/07/2023]
Abstract
Clarifying allele frequencies of disease-related genetic variants in a population is important in genomic medicine; however, such data is not yet available for the Japanese population. To estimate frequencies of actionable pathogenic variants in the Japanese population, we examined the reported pathological variants in genes recommended by the American College of Medical Genetics and Genomics (ACMG) in our reference panel of genomic variations, 2KJPN, which was created by whole-genome sequencing of 2049 individuals of the resident cohort of the Tohoku Medical Megabank Project. We searched for pathogenic variants in 2KJPN for 57 autosomal ACMG-recommended genes responsible for 26 diseases and then examined their frequencies. By referring to public databases of pathogenic variations, we identified 143 reported pathogenic variants in 2KJPN for the 57 ACMG recommended genes based on a classification system. At the individual level, 21% of the individuals were found to have at least one reported pathogenic allele. We then conducted a literature survey to review the variants and to check for evidence of pathogenicity. Our results suggest that a substantial number of people have reported pathogenic alleles for the ACMG genes, and reviewing variants is indispensable for constructing the information infrastructure of genomic medicine for the Japanese population.
Collapse
|
9
|
Bianchi F, Maccaroni E, Belvederesi L, Brugiati C, Giampieri R, Bini F, Bracci R, Pagliaretta S, Del Prete M, Piva F, Mandolesi A, Scarpelli M, Berardi R. A germline missense mutation in exon 3 of the MSH2 gene in a Lynch syndrome family: correlation with phenotype and localization assay. Fam Cancer 2017; 17:215-224. [PMID: 28785832 DOI: 10.1007/s10689-017-0030-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Lynch syndrome is caused by germline mutations in any of the MisMatch Repair (MMR) genes. About 37% of MSH2 variants are missense variants causing single amino-acid substitutions. Whether missense variants affect the normal function of MMR proteins is crucial both to provide affected families a more accurate risk assessment and to offer predictive testing to family members. Here we report one family, fulfilling both Amsterdam I and II criteria and Bethesda guidelines, referred to our center for genetic counselling. The proband and some of her relatives have been investigated for microsatellite instability (MSI), immunohistochemical MMR protein staining, direct sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA). Also Subcellular Localization Assay and Splice site predictions analyses were used. A germline missense variant of uncertain significance (exon 3, p.Val161Asp) was found in MSH2 gene in proband and in some relatives. The variant was associated with lack of expression of MSH2 protein (DMMR) and MSI-High status in tumour tissues. The localization assay of the MSH2 protein showed an abnormal subcellular localization pattern of the corresponding protein. Finally, splice-site prediction analysis ruled out a potential role of new splice sites as the cause behind the lack of expression of MSH2 protein and we suppose a potential correlation with other forms of post-transcriptional regulation (circular RNAs). The variant here reported shows a high correlation with phenotype and is located in an evolutionary conserved domain. The localization assay also suggest a potential pathogenic role, thus supporting further research on this matter.
Collapse
Affiliation(s)
- Francesca Bianchi
- Clinica Oncologica e Centro Regionale di Genetica Oncologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Via Conca 71, 60126, Ancona, Italy
| | - Elena Maccaroni
- Clinica Oncologica e Centro Regionale di Genetica Oncologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Via Conca 71, 60126, Ancona, Italy.
| | - Laura Belvederesi
- Clinica Oncologica e Centro Regionale di Genetica Oncologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Via Conca 71, 60126, Ancona, Italy
| | - Cristiana Brugiati
- Clinica Oncologica e Centro Regionale di Genetica Oncologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Via Conca 71, 60126, Ancona, Italy
| | - Riccardo Giampieri
- Clinica Oncologica e Centro Regionale di Genetica Oncologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Via Conca 71, 60126, Ancona, Italy
| | - Federica Bini
- Clinica Oncologica e Centro Regionale di Genetica Oncologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Via Conca 71, 60126, Ancona, Italy
| | - Raffaella Bracci
- Clinica Oncologica e Centro Regionale di Genetica Oncologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Via Conca 71, 60126, Ancona, Italy
| | - Silvia Pagliaretta
- Clinica Oncologica e Centro Regionale di Genetica Oncologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Via Conca 71, 60126, Ancona, Italy
| | - Michela Del Prete
- Clinica Oncologica e Centro Regionale di Genetica Oncologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Via Conca 71, 60126, Ancona, Italy
| | - Francesco Piva
- Dipartimento di Scienze Cliniche Specialistiche e Odontostomatologiche, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Ancona, Italy
| | - Alessandra Mandolesi
- Anatomia Patologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Ancona, Italy
| | - Marina Scarpelli
- Anatomia Patologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Ancona, Italy
| | - Rossana Berardi
- Clinica Oncologica e Centro Regionale di Genetica Oncologica, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Via Conca 71, 60126, Ancona, Italy
| |
Collapse
|
10
|
Abstract
Defects in the DNA mismatch repair (MMR) proteins, result in a phenotype called microsatellite instability (MSI), occurring in up to 15% of sporadic colorectal cancers. Approximately one quarter of colon cancers with deficient MMR (dMMR) develop as a result of an inherited predisposition syndrome, Lynch syndrome (formerly known as HNPCC). It is essential to identify patients who potentially have Lynch syndrome, as not only they, but also family members, may require screening and monitoring. Diagnostic criteria have been developed, based primarily on Western populations, and several methodologies are available to identify dMMR tumours, including immunohistochemistry and microsatellite testing. These criteria have provided evidence supporting the introduction of reflex testing. Yet, it is becoming increasingly clear that tests have a limited sensitivity and specificity and may yet be superseded by next generation sequencing. In this review, the limitations of diagnostic criteria are discussed, and current and emerging screening technologies explained. There is now useful evidence supporting the prognostic and predictive value of dMMR status in colorectal tumours, but much less is known about their value in extracolonic tumours, that may also feature in Lynch syndrome. This review assesses current literature relating to dMMR in endometrial, ovarian, gastric and melanoma cancers, which it would seem, may benefit from large-scale clinical trials in order to further close the gap in knowledge between colorectal and extracolonic tumours.
Collapse
Affiliation(s)
- Susan Richman
- Department of Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, St. James University Hospital, Leeds, LS9 7TF, UK
| |
Collapse
|
11
|
Pinheiro M, Pinto C, Peixoto A, Veiga I, Mesquita B, Henrique R, Lopes P, Sousa O, Fragoso M, Dias LM, Baptista M, Marinho C, Mangold E, Vaccaro C, Evans DG, Farrington S, Dunlop MG, Teixeira MR. The MSH2 c.388_389del mutation shows a founder effect in Portuguese Lynch syndrome families. Clin Genet 2012; 84:244-50. [PMID: 23170986 DOI: 10.1111/cge.12062] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 11/14/2012] [Accepted: 11/14/2012] [Indexed: 01/13/2023]
Abstract
The MSH2 c.388_389del mutation has occasionally been described in Lynch families worldwide. At the Portuguese Oncology Institute in Porto, Portugal, we have identified 16 seemingly unrelated families with this germline mutation. To evaluate if this alteration is a founder or a recurrent mutation we performed haplotype analysis in the 16 Portuguese index cases and 55 relatives, as well as in four index cases and 13 relatives reported from Germany, Scotland, England, and Argentina. In the Portuguese families we observed a shared haplotype of approximately 10 Mb and all were originated from the north of Portugal. These results suggest that this alteration is a founder mutation in Portugal with a relatively recent origin. In the reported families outside Portugal with this mutation different haplotype backgrounds were observed, supporting the hypothesis that it occurred de novo on multiple occasions. We also conclude that the high proportion of families with the MSH2 c.388_389del mutation indicates that screening for this alteration as a first step may be cost-effective in the genetic testing of Lynch syndrome suspects of Portuguese ancestry, especially those originating from the north of Portugal.
Collapse
Affiliation(s)
- M Pinheiro
- Department of Genetics, Portuguese Oncology Institute, Porto, Portugal
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Belvederesi L, Bianchi F, Loretelli C, Bracci R, Cascinu S, Cellerino R. Sub-cellular localization analysis of MSH6 missense mutations does not reveal an overt MSH6 nuclear transport impairment. Fam Cancer 2012; 11:675-80. [PMID: 22851212 DOI: 10.1007/s10689-012-9558-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Nearly one-third of the identified MSH6 germline mutations deal with single amino acid substitutions. For an effective genetic counselling it is necessary to clearly elucidate by functional tools the specific sub-processes underlying the mismatch repair (MMR) misfunctioning in MSH6 non-truncating mutants. Since the MMR repair pathway occurs in the nucleus, we suppose the impairment of MutSα nuclear trafficking to be a possible Lynch syndrome susceptibility causative mechanism. In the present study the MMR status of the tumour, the main clinical features of mutation carriers and population data associated to the MSH6 missense variants, were complemented with computational data about tolerability predictions and amino acid substitution conservation. The selected panel of ten potentially pathogenic MSH6 mutations was analyzed in a homologous expression system for possible deleterious effects on nucleo-cytoplasmic shuttling through the assessment of the sub-cellular localization of the corresponding mutated proteins. Localization analysis results do not reveal an apparent role of MSH6 missense mutations in nuclear import impairment and provide the first hint to exclude the MSH6 nuclear translocation sub-process as a possible causative mechanisms of MMR misfunctioning.
Collapse
|
13
|
Khanra K, Panda K, Bhattacharya C, Mitra A, Sarkar R, Bhattacharyya N. Association of Two Polymorphisms of DNA Polymerase Beta in Exon-9 and Exon-11 with Ovarian Carcinoma in India. Asian Pac J Cancer Prev 2012; 13:1321-4. [DOI: 10.7314/apjcp.2012.13.4.1321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
14
|
George Priya Doss C, Rajasekaran R, Arjun P, Sethumadhavan R. Prioritization of candidate SNPs in colon cancer using bioinformatics tools: An alternative approach for a cancer biologist. Interdiscip Sci 2010; 2:320-46. [DOI: 10.1007/s12539-010-0003-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 05/05/2010] [Accepted: 05/12/2010] [Indexed: 12/18/2022]
|
15
|
Xie J, Guillemette S, Peng M, Gilbert C, Buermeyer A, Cantor SB. An MLH1 mutation links BACH1/FANCJ to colon cancer, signaling, and insight toward directed therapy. Cancer Prev Res (Phila) 2010; 3:1409-16. [PMID: 20978114 DOI: 10.1158/1940-6207.capr-10-0118] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Defects in MLH1, as with other mismatch repair (MMR) proteins, are the primary cause of hereditary nonpolyposis colon cancer (HNPCC). Mutations in MMR genes often disrupt mismatch repair and MMR signaling functions. However, some HNPCC-associated mutations have unknown pathogenicity. Here, we uncover an MLH1 clinical mutation with a leucine (L)-to-histidine (H) amino acid change at position 607 that ablates MLH1 binding to FANCJ. Given that a DNA helicase is not essential for mammalian MMR in vitro, we considered that loss of MLH1 binding to FANCJ could alter MMR signaling. Consistent with this hypothesis, FANCJ-deficient cells exhibit delayed MMR signaling and apoptotic responses that generate resistance to agents that induce O(6)-methylguanine lesions. Our data indicate that the delay in MMR signaling provides time for the methylguanine methyltransferase (MGMT) enzyme to reverse DNA methylation. In essence, FANCJ deficiency alters the competition between two pathways: MGMT-prosurvival versus MMR-prodeath. This outcome could explain the HNPCC familial cancers that present as microsatellite stable and with intact MMR, such as MLH(L607H). Importantly, the link between FANCJ and HNPCC provides insight toward directed therapies because loss of the FANCJ/MLH1 interaction also uniquely sensitizes cells to DNA cross-linking agents.
Collapse
Affiliation(s)
- Jenny Xie
- 1Department of Cancer Biology, University of Massachusetts Medical School, Women's Cancers Program, UMass Memorial Cancer Center, Worcester, Massachusetts 01605, USA
| | | | | | | | | | | |
Collapse
|
16
|
Vogelsang M, Comino A, Zupanec N, Hudler P, Komel R. Assessing pathogenicity of MLH1 variants by co-expression of human MLH1 and PMS2 genes in yeast. BMC Cancer 2009; 9:382. [PMID: 19863800 PMCID: PMC2773791 DOI: 10.1186/1471-2407-9-382] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 10/28/2009] [Indexed: 12/29/2022] Open
Abstract
Background Loss of DNA mismatch repair (MMR) in humans, mainly due to mutations in the hMLH1 gene, is linked to hereditary nonpolyposis colorectal cancer (HNPCC). Because not all MLH1 alterations result in loss of MMR function, accurate characterization of variants and their classification in terms of their effect on MMR function is essential for reliable genetic testing and effective treatment. To date, in vivo assays for functional characterization of MLH1 mutations performed in various model systems have used episomal expression of the modified MMR genes. We describe here a novel approach to determine accurately the functional significance of hMLH1 mutations in vivo, based on co-expression of human MLH1 and PMS2 in yeast cells. Methods Yeast MLH1 and PMS1 genes, whose protein products form the MutLα complex, were replaced by human orthologs directly on yeast chromosomes by homologous recombination, and the resulting MMR activity was tested. Results The yeast strain co-expressing hMLH1 and hPMS2 exhibited the same mutation rate as the wild-type. Eight cancer-related MLH1 variants were introduced, using the same approach, into the prepared yeast model, and their effect on MMR function was determined. Five variants (A92P, S93G, I219V, K618R and K618T) were classified as non-pathogenic, whereas variants T117M, Y646C and R659Q were characterized as pathogenic. Conclusion Results of our in vivo yeast-based approach correlate well with clinical data in five out of seven hMLH1 variants and the described model was thus shown to be useful for functional characterization of MLH1 variants in cancer patients found throughout the entire coding region of the gene.
Collapse
Affiliation(s)
- Matjaz Vogelsang
- Department for Biosynthesis and Biotransformation, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia.
| | | | | | | | | |
Collapse
|
17
|
Arnold S, Buchanan DD, Barker M, Jaskowski L, Walsh MD, Birney G, Woods MO, Hopper JL, Jenkins MA, Brown MA, Tavtigian SV, Goldgar DE, Young JP, Spurdle AB. Classifying MLH1 and MSH2 variants using bioinformatic prediction, splicing assays, segregation, and tumor characteristics. Hum Mutat 2009; 30:757-70. [PMID: 19267393 PMCID: PMC2707453 DOI: 10.1002/humu.20936] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Reliable methods for predicting functional consequences of variants in disease genes would be beneficial in the clinical setting. This study was undertaken to predict, and confirm in vitro, splicing aberrations associated with mismatch repair (MMR) variants identified in familial colon cancer patients. Six programs were used to predict the effect of 13 MLH1 and 6 MSH2 gene variants on pre-mRNA splicing. mRNA from cycloheximide-treated lymphoblastoid cell lines of variant carriers was screened for splicing aberrations. Tumors of variant carriers were tested for microsatellite instability and MMR protein expression. Variant segregation in families was assessed using Bayes factor causality analysis. Amino acid alterations were examined for evolutionary conservation and physicochemical properties. Splicing aberrations were detected for 10 variants, including a frameshift as a minor cDNA product, and altered ratio of known alternate splice products. Loss of splice sites was well predicted by splice-site prediction programs SpliceSiteFinder (90%) and NNSPLICE (90%), but consequence of splice site loss was less accurately predicted. No aberrations correlated with ESE predictions for the nine exonic variants studied. Seven of eight missense variants had normal splicing (88%), but only one was a substitution considered neutral from evolutionary/physicochemical analysis. Combined with information from tumor and segregation analysis, and literature review, 16 of 19 variants were considered clinically relevant. Bioinformatic tools for prediction of splicing aberrations need improvement before use without supporting studies to assess variant pathogenicity. Classification of mismatch repair gene variants is assisted by a comprehensive approach that includes in vitro, tumor pathology, clinical, and evolutionary conservation data.
Collapse
Affiliation(s)
- Sven Arnold
- Genetics and Population Health Division, Queensland Institute of Medical Research, Brisbane, Australia
| | - Daniel D. Buchanan
- Genetics and Population Health Division, Queensland Institute of Medical Research, Brisbane, Australia
- School of Medicine, University of Queensland, Brisbane, Australia
| | - Melissa Barker
- Genetics and Population Health Division, Queensland Institute of Medical Research, Brisbane, Australia
| | - Lesley Jaskowski
- Genetics and Population Health Division, Queensland Institute of Medical Research, Brisbane, Australia
| | - Michael D. Walsh
- Genetics and Population Health Division, Queensland Institute of Medical Research, Brisbane, Australia
- School of Medicine, University of Queensland, Brisbane, Australia
| | - Genevieve Birney
- Genetics and Population Health Division, Queensland Institute of Medical Research, Brisbane, Australia
| | - Michael O. Woods
- Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - John L. Hopper
- Centre for Genetic Epidemiology, University of Melbourne, Melbourne, Australia
| | - Mark A. Jenkins
- Centre for Genetic Epidemiology, University of Melbourne, Melbourne, Australia
| | - Melissa A. Brown
- School of Medicine, and School of Molecular and Microbial Sciences, University of Queensland, Brisbane
| | | | - David E. Goldgar
- Department of Dermatology, University of Utah, Salt Lake City, Utah, USA
| | - Joanne P. Young
- Genetics and Population Health Division, Queensland Institute of Medical Research, Brisbane, Australia
- School of Medicine, University of Queensland, Brisbane, Australia
| | - Amanda B. Spurdle
- Genetics and Population Health Division, Queensland Institute of Medical Research, Brisbane, Australia
- School of Medicine, University of Queensland, Brisbane, Australia
| |
Collapse
|
18
|
Doss CGP, Sethumadhavan R. Investigation on the role of nsSNPs in HNPCC genes--a bioinformatics approach. J Biomed Sci 2009; 16:42. [PMID: 19389263 PMCID: PMC2682794 DOI: 10.1186/1423-0127-16-42] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Accepted: 04/24/2009] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND A central focus of cancer genetics is the study of mutations that are causally implicated in tumorigenesis. The identification of such causal mutations not only provides insight into cancer biology but also presents anticancer therapeutic targets and diagnostic markers. Missense mutations are nucleotide substitutions that change an amino acid in a protein, the deleterious effects of these mutations are commonly attributed to their impact on primary amino acid sequence and protein structure. METHODS The method to identify functional SNPs from a pool, containing both functional and neutral SNPs is challenging by experimental protocols. To explore possible relationships between genetic mutation and phenotypic variation, we employed different bioinformatics algorithms like Sorting Intolerant from Tolerant (SIFT), Polymorphism Phenotyping (PolyPhen), and PupaSuite to predict the impact of these amino acid substitutions on protein activity of mismatch repair (MMR) genes causing hereditary nonpolyposis colorectal cancer (HNPCC). RESULTS SIFT classified 22 of 125 variants (18%) as 'Intolerant." PolyPhen classified 40 of 125 amino acid substitutions (32%) as "Probably or possibly damaging". The PupaSuite predicted the phenotypic effect of SNPs on the structure and function of the affected protein. Based on the PolyPhen scores and availability of three-dimensional structures, structure analysis was carried out with the major mutations that occurred in the native protein coded by MSH2 and MSH6 genes. The amino acid residues in the native and mutant model protein were further analyzed for solvent accessibility and secondary structure to check the stability of the proteins. CONCLUSION Based on this approach, we have shown that four nsSNPs, which were predicted to have functional consequences (MSH2-Y43C, MSH6-Y538S, MSH6-S580L, and MSH6-K854M), were already found to be associated with cancer risk. Our study demonstrates the presence of other deleterious mutations and also endorses with in vivo experimental studies.
Collapse
Affiliation(s)
- C George Priya Doss
- Bioinformatics Division, School of Biotechnology, Chemical and Biomedical Engineering, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India.
| | | |
Collapse
|
19
|
Spurdle AB, Couch FJ, Hogervorst FBL, Radice P, Sinilnikova OM. Prediction and assessment of splicing alterations: implications for clinical testing. Hum Mutat 2008; 29:1304-13. [PMID: 18951448 DOI: 10.1002/humu.20901] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Sequence variants that may result in splicing alterations are a particular class of inherited variants for which consequences can be more readily assessed, using a combination of bioinformatic prediction methods and in vitro assays. There is also a general agreement that a variant would invariably be considered pathogenic on the basis of convincing evidence that it results in transcript(s) carrying a premature stop codon or an in-frame deletion disrupting known functional domain(s). This commentary discusses current practices used to assess the clinical significance of this class of variants, provides suggestions to improve assessment, and highlights the issues involved in routine assessment of potential splicing aberrations. We conclude that classification of sequence variants that may alter splicing is greatly enhanced by supporting in vitro analysis. Additional studies that assess large numbers of variants for induction of splicing aberrations and exon skipping are needed to define the contribution of splicing/exon skipping to cancer and disease. These studies will also provide the impetus for development of algorithms that better predict splicing patterns. To facilitate variant classification and development of more specific bioinformatic tools, we call for the deposition of all laboratory data from splicing analyses into national and international databases.
Collapse
Affiliation(s)
- Amanda B Spurdle
- Genetics and Population Health Division, Queensland Institute of Medical Research, Brisbane, Australia.
| | | | | | | | | | | |
Collapse
|
20
|
Pande M, Amos CI, Osterwisch DR, Chen J, Lynch PM, Broaddus R, Frazier ML. Genetic variation in genes for the xenobiotic-metabolizing enzymes CYP1A1, EPHX1, GSTM1, GSTT1, and GSTP1 and susceptibility to colorectal cancer in Lynch syndrome. Cancer Epidemiol Biomarkers Prev 2008; 17:2393-401. [PMID: 18768509 DOI: 10.1158/1055-9965.epi-08-0326] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Individuals with Lynch syndrome are predisposed to cancer due to an inherited DNA mismatch repair gene mutation. However, there is significant variability observed in disease expression likely due to the influence of other environmental, lifestyle, or genetic factors. Polymorphisms in genes encoding xenobiotic-metabolizing enzymes may modify cancer risk by influencing the metabolism and clearance of potential carcinogens from the body. In this retrospective analysis, we examined key candidate gene polymorphisms in CYP1A1, EPHX1, GSTT1, GSTM1, and GSTP1 as modifiers of age at onset of colorectal cancer among 257 individuals with Lynch syndrome. We found that subjects heterozygous for CYP1A1 I462V (c.1384A>G) developed colorectal cancer 4 years earlier than those with the homozygous wild-type genotype (median ages, 39 and 43 years, respectively; log-rank test P = 0.018). Furthermore, being heterozygous for the CYP1A1 polymorphisms, I462V and Msp1 (g.6235T>C), was associated with an increased risk for developing colorectal cancer [adjusted hazard ratio for AG relative to AA, 1.78; 95% confidence interval, 1.16-2.74; P = 0.008; hazard ratio for TC relative to TT, 1.53; 95% confidence interval, 1.06-2.22; P = 0.02]. Because homozygous variants for both CYP1A1 polymorphisms were rare, risk estimates were imprecise. None of the other gene polymorphisms examined were associated with an earlier onset age for colorectal cancer. Our results suggest that the I462V and Msp1 polymorphisms in CYP1A1 may be an additional susceptibility factor for disease expression in Lynch syndrome because they modify the age of colorectal cancer onset by up to 4 years.
Collapse
Affiliation(s)
- Mala Pande
- Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | | | | | | | | | | | | |
Collapse
|
21
|
Ollila S, Bebek DD, Greenblatt M, Nyström M. Uncertain pathogenicity of MSH2
variants N127S and G322D challenges their classification. Int J Cancer 2008; 123:720-4. [DOI: 10.1002/ijc.23573] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
22
|
Barnetson RA, Cartwright N, van Vliet A, Haq N, Drew K, Farrington S, Williams N, Warner J, Campbell H, Porteous ME, Dunlop MG. Classification of ambiguous mutations in DNA mismatch repair genes identified in a population-based study of colorectal cancer. Hum Mutat 2008; 29:367-74. [PMID: 18033691 DOI: 10.1002/humu.20635] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Identification of germline mutations in DNA mismatch repair genes in colorectal cancer probands without an extensive family history can be problematic when ascribing relevance to cancer causation. We undertook a structured assessment of the disease-causing potential of sequence variants identified in a prospective, population-based study of 932 colorectal cancer patients, diagnosed at <55 years of age. Patient samples were screened for germline mutations in MLH1, MSH2, and MSH6. Of 110 carriers, 74 (67%) had one of 33 rare variants of uncertain pathogenicity (12 MLH1, 11 MSH2, and 10 MSH6). Pathogenicity was assessed by determining segregation in families, allele frequency in large numbers of unaffected controls, effect on mRNA for putative splice-site mutations, effect on protein function by bioinformatic analysis and tumor microsatellite instability (MSI) status and DNA mismatch repair protein expression by immunohistochemistry. Because of the ambiguous nature of these variants and lack of concordance between functional assays and control allele frequency, we devised a scoring system to rank the degree of support for a pathogenic role. MLH1 c.200G>A p.G67E, MLH1 c.2041G>A p.A681T, and MSH2 c.2634+5G>C were categorized as pathogenic through assimilation of all available data, while 14 variants were categorized as benign (seven MLH1, three MSH2, and four MSH6). Interestingly, there is tentative evidence suggesting a possible protective effect of three variants (MLH1 c.2066A>G pQ689R, c.2146G>A p.V716M, and MSH2 c.965G>A p.G322D). These findings support a causal link with colorectal cancer for several DNA mismatch repair gene variants. However, the majority of missense changes are likely to be inconsequential polymorphisms.
Collapse
Affiliation(s)
- Rebecca A Barnetson
- University of Edinburgh Cancer Research Centre, School of Molecular and Clinical Medicine and Medical Research Council (MRC) Human Genetics Unit, Western General Hospital, Edinburgh, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Yan HL, Hao LQ, Jin HY, Xing QH, Xue G, Mei Q, He J, He L, Sun SH. Clinical features and mismatch repair genes analyses of Chinese suspected hereditary non-polyposis colorectal cancer: a cost-effective screening strategy proposal. Cancer Sci 2008; 99:770-80. [PMID: 18307539 DOI: 10.1111/j.1349-7006.2008.00737.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
China has the largest numbers of hereditary non-polyposis colorectal cancer (HNPCC) patients based on its population of 1.4 billion. However, the clinical data and mismatch repair (MMR) gene analyses have been limited. Here we performed microsatellite instability (MSI) and immunohistochemistry (IHC) analyses on a series of patients with a high-risk for HNPCC: 61 patients with family histories fulfilling Amsterdam criteria II (ACII-HNPCC) or suspected HNPCC criteria (S-HNPCC), and 106 early onset colorectal cancer (CRC) patients. Sixty late-onset CRC patients were used as control. Methylation of the hMLH1 promoter was analyzed on tumors lacking hMLH1 expression. MMR germ-line mutations were screened on patients with tumors classified as MSI-H/L or negative for IHC. We identified 27 germ-line MMR variants in the 167 patients with a high-risk for HNPCC while only one germ-line mutation in hMSH6 was found in the late-onset CRC group. Of those, 23 were pathogenic mutations. The high incidence of gastric and hepatobiliary cancers coupled with the increasing number of small families in China reduces the sensitivity (43.5%, 30.4%) and positive predictive value (PPV) (45.5%, 17.9%) of the ACII- or S-HNPCC criteria. MSI or IHC testing are highly sensitive in detecting pathogenic mutations (sensitivities = 91.3% and 95.6%, respectively), but the PPVs are quite low (25.6% and 27.8%, respectively). Considering that all 12 tumors with pathogenic mutations in hMLH1 also showed promoter unmethylation, the sensitivity of IHC in conjunction with hMLH1 promoter methylation analysis is not reduced, but the PPV was increased from 27.8% to 61.1%, and the total cost was greatly reduced.
Collapse
Affiliation(s)
- Hong-Li Yan
- Department of Medical Genetics, College of Basic Medical Sciences, Second Military Medical University, Shanghai 200433, China
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Ou J, Niessen RC, Lützen A, Sijmons RH, Kleibeuker JH, de Wind N, Rasmussen LJ, Hofstra RMW. Functional analysis helps to clarify the clinical importance of unclassified variants in DNA mismatch repair genes. Hum Mutat 2007; 28:1047-54. [PMID: 17594722 DOI: 10.1002/humu.20580] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome is caused by DNA variations in the DNA mismatch repair (MMR) genes MSH2, MLH1, MSH6, and PMS2. Many of the mutations identified result in premature termination of translation and thus in loss-of-function of the encoded mutated protein. These DNA variations are thought to be pathogenic mutations. However, some patients carry other DNA mutations, referred to as unclassified variants (UVs), which do not lead to such a premature termination of translation; it is not known whether these contribute to the disease phenotype or merely represent rare polymorphisms. This is a major problem which has direct clinical consequences. Several criteria can be used to classify these UVs, such as: whether they segregate with the disease within pedigrees, are absent in control individuals, show a change of amino acid polarity or size, provoke an amino acid change in a domain that is evolutionary conserved and/or shared between proteins belonging to the same protein family, or show altered function in an in vitro assay. In this review we discuss the various functional assays reported for the HNPCC-associated MMR proteins and the outcomes of these tests on UVs identified in patients diagnosed with or suspected of having HNPCC. We conclude that a large proportion of MMR UVs are likely to be pathogenic, suggesting that missense variants of MMR proteins do indeed play a role in HNPCC.
Collapse
Affiliation(s)
- Jianghua Ou
- Department of Genetics, University Medical Center Groningen, Groningen, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Bianchi F, Galizia E, Porfiri E, Belvederesi L, Catalani R, Loretelli C, Bracci R, Bearzi I, Turchi C, Viel A, Cellerino R. A missense germline mutation in exon 7 of the MSH2 gene in a HNPCC family from center-Italy. Fam Cancer 2007; 6:97-102. [PMID: 17165155 DOI: 10.1007/s10689-006-9110-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 10/17/2006] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Hereditary Non-Polyposis Colorectal Cancer (HNPCC) is an autosomal dominant inherited disease predisposing to the development of colorectal cancers and several other malignancies (endometrium, ovaries, stomach, small bowel, hepatobiliary and urinary tract). HNPCC is caused by germline mutations in any of the MisMatch Repair (MMR) genes. Mutations in MLH1 and MSH2 account for almost 90% of all identified ones. About 15% of mutations identified in MSH2 are missense ones. PATIENTS AND METHODS We studied one family, fulfilling Amsterdam II criteria, referred to our Center for genetic counselling. The proband, and some of her relatives, have been investigated for microsatellite instability (MSI), immunohistochemical MMR protein staining and by direct sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA). RESULTS All patients carried the same novel MSH2 germline missense mutation (R359S) in exon 7, which determines the substitution of an Arginine, which is a basic amino acid, with a polar Serine residue (R359S). The mutation was associated with lack of expression of MSH2 protein and high microsatellite instability in tumour tissues. The same mutation has been detected in one healthy relative. CONCLUSIONS The mutation here reported shows a high correlation with phenotype. The mutation is located in an evolutionary conserved domain. Taken together, our findings suggest evidence that the amino acid substitution can be interpreted as pathogenetic.
Collapse
Affiliation(s)
- Francesca Bianchi
- Istituto di Medicina Clinica e Biotecnologie Applicate-Oncologia Medica, Università Politecnica delle Marche, via Tronto, 60020 Ancona, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Takahashi M, Shimodaira H, Andreutti-Zaugg C, Iggo R, Kolodner RD, Ishioka C. Functional analysis of human MLH1 variants using yeast and in vitro mismatch repair assays. Cancer Res 2007; 67:4595-604. [PMID: 17510385 DOI: 10.1158/0008-5472.can-06-3509] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The functional characterization of nonsynonymous single nucleotide polymorphisms in human mismatch repair (MMR) genes has been critical to evaluate their pathogenicity for hereditary nonpolyposis colorectal cancer. We previously established an assay for detecting loss-of-function mutations in the MLH1 gene using a dominant mutator effect of human MLH1 expressed in Saccharomyces cerevisiae. The purpose of this study is to extend the functional analyses of nonsynonymous single nucleotide polymorphisms in the MLH1 gene both in quality and in quantity, and integrate the results to evaluate the variants for pathogenic significance. The 101 MLH1 variants, which covered most of the reported MLH1 nonsynonymous single nucleotide polymorphisms and consisted of one 3-bp deletion, 1 nonsense and 99 missense variants, were examined for the dominant mutator effect by three yeast assays and for the ability of the variant to repair a heteroduplex DNA with mismatch bases by in vitro MMR assay. There was diversity in the dominant mutator effects and the in vitro MMR activities among the variants. The majority of functionally inactive variants were located around the putative ATP-binding pocket of the NH(2)-terminal domain or the whole region of the COOH-terminal domain. Integrated functional evaluations contribute to a better prediction of the cancer risk in individuals or families carrying MLH1 variants and provide insights into the function-structure relationships in MLH1.
Collapse
Affiliation(s)
- Masanobu Takahashi
- Department of Clinical Oncology, Institute of Development, Aging and Cancer, Tohoku University Hospital, Tohoku University, Sendai, Japan
| | | | | | | | | | | |
Collapse
|
27
|
Ollila S, Sarantaus L, Kariola R, Chan P, Hampel H, Holinski-Feder E, Macrae F, Kohonen-Corish M, Gerdes AM, Peltomäki P, Mangold E, de la Chapelle A, Greenblatt M, Nyström M. Pathogenicity of MSH2 missense mutations is typically associated with impaired repair capability of the mutated protein. Gastroenterology 2006; 131:1408-17. [PMID: 17101317 DOI: 10.1053/j.gastro.2006.08.044] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Accepted: 07/12/2006] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Inherited deleterious mutations in mismatch repair genes MLH1, MSH2, and MSH6 predispose to hereditary nonpolyposis colorectal cancer. A major diagnostic challenge is the difficulty in evaluating the pathogenicity of missense mutations. Previously we showed that most missense variants in MSH6 do not impair MMR capability and are associated with no or low cancer susceptibility, whereas in MLH1, functional studies distinguished nontruncating mutations with severe defects from those not or slightly impaired in protein expression or function. The present study was undertaken to evaluate the pathogenicity of inherited missense mutations in MSH2. METHODS Fifteen mutated MSH2 proteins including 14 amino acid substitutions and one in-frame deletion were tested for expression/stability, MSH2/MSH6 interaction, and repair efficiency. The genetic and biochemical data were correlated with the clinical data. Comparative sequence analysis was performed to assess the value of sequence homology as a tool for predicting functional results. RESULTS None of the studied MSH2 mutations destroyed the protein or abolished MSH2/MSH6 interaction, whereas 12 mutations impaired the repair capability of the protein. Comparative sequence analysis correctly predicted functional studies for 13 of 14 amino acid substitutions. CONCLUSIONS Interpretation was pathogenic for 12, nonpathogenic for 2, and contradictory for 1 mutation. The pathogenicity could not be distinguished unambiguously by phenotypic characteristics, although correlation between the absence of staining for MSH2 and pathogenicity of the missense mutation was notable. Unlike in MSH6 and MLH1, the pathogenicity of missense mutations in MSH2 was always associated with impaired repair capability of the mutated protein.
Collapse
Affiliation(s)
- Saara Ollila
- Department of Biological and Environmental Sciences, Genetics, University of Helsinki, Helsinki, Finland
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Spaepen M, Vankeirsbilck B, Van Opstal S, Tejpar S, Van Cutsem E, Geboes K, Legius E, Matthijs G. Germline mutations of the hMLH1 and hMSH2 mismatch repair genes in Belgian hereditary nonpolyposis colon cancer (HNPCC) patients. Fam Cancer 2006; 5:179-89. [PMID: 16736289 DOI: 10.1007/s10689-005-5958-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Accepted: 12/08/2005] [Indexed: 01/21/2023]
Abstract
BACKGROUND Hereditary nonpolyposis colon cancer (HNPCC-Lynch syndrome) is caused by mutations in genes involved in DNA mismatch repair (MMR), mostly in the hMLH1 and hMSH2 genes. The mutation spectrum in the Belgian population is still poorly documented. AIM To report our experience on the mutation screening in Belgian familial colorectal cancer (CRC) patients, including the investigation of the pathogenicity of the missense and splice mutations. To increase the mutation detection rate by selecting the target population. METHODS Two hundred and twenty five Belgian patients with familial clustering of CRC were genetically tested. Point mutations in the hMLH1 and hMSH2 genes were screened by denaturing gradient gel electrophoresis (DGGE) followed by direct sequencing. Genomic deletions and duplications were assessed by multiplex ligase dependent probe amplification (MLPA) and multiplex PCR. Missense mutations were examined for pathogenicity by means of cosegregation of the mutation with the disease, microsatellite instability (MSI) in tumors, immunohistochemical staining of tumors and determination of the population frequency of the particular mutation. RESULTS Twenty five pathogenic mutations were identified from which 16 were novel: 7 frameshifts, one in frame deletion, 5 genomic deletions, 5 splice defects, 4 nonsense (stop) mutations and 3 missense mutations which were classified as pathogenic (out of 10 missense mutations). In retrospect, a mutation detection rate of 71% was obtained if MSI was used as a supplementary selection criterion in addition to familial clustering. CONCLUSION Different types of pathogenic mutations in the hMLH1 and hMSH2 genes were identified in a Belgian CRC group with familial clustering. The mutation detection yield drastically increased by preliminar selection of those familial CRC patients with a microsatellite instable tumor. Considerable attention went to the assessment of the pathogenicity of the missense mutations. In practice, the cosegregation with the disease was the most relevant criterion.
Collapse
Affiliation(s)
- M Spaepen
- Center for Human Genetics, University Hospital of Leuven, Leuven, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Belvederesi L, Bianchi F, Loretelli C, Gagliardini D, Galizia E, Bracci R, Rosati S, Bearzi I, Viel A, Cellerino R, Porfiri E. Assessing the pathogenicity of MLH1 missense mutations in patients with suspected hereditary nonpolyposis colorectal cancer: correlation with clinical, genetic and functional features. Eur J Hum Genet 2006; 14:853-9. [PMID: 16724012 DOI: 10.1038/sj.ejhg.5201628] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Assessing the pathogenicity of missense mutations of MLH1 and MSH2 is critical to counsel patients with suspected hereditary nonpolyposis colorectal cancer (HNPCC). Approximately 32% of all MLH1 mutations and 18% of MSH2 mutations are missense variants which often have an uncertain genetic significance. To assess the pathogenicity of four MLH1 missense mutations which were found in five patients with suspected HNPCC, P648S (CCC --> TCC), L559R (CTG --> CGG), K618A (AAG --> GCG), Y646C (TAT --> TGT), we studied their ability to disrupt MLH1 protein function and their relationship with all those clinical, genetic and pathological features which are typical of this syndrome. Our results indicated that the P648S and L559R mutations were probably pathogenic because they disrupted MLH1 protein interaction with its partner PMS2 in vitro and abolished MLH1 expression in HCT116 cells. In addition these variants were associated with features often found in HNPCC patients: in particular high microsatellite instability, occurrence of high grade tumours and, in one case, strong family history. The pathogenicity of the K618A and Y646C mutations was questionable as their correlation with features typical of HNPCC was low and the outcome of the functional analysis was ambiguous. These observations suggested that a clinically usable assessment of the pathogenicity of MLH missense variants can be achieved through the analysis of multiple mutation characteristics among which loss of protein function, occurrence of microsatellite instability and family history seemed to have a predominant role.
Collapse
Affiliation(s)
- Laura Belvederesi
- Oncologia Medica, Facolta' di Medicina e Chirurgia, Università Politecnica delle Marche, Ancona, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Raevaara TE, Korhonen MK, Lohi H, Hampel H, Lynch E, Lönnqvist KE, Holinski-Feder E, Sutter C, McKinnon W, Duraisamy S. Functional significance and clinical phenotype of nontruncating mismatch repair variants of MLH1. Gastroenterology. 2005;129:537-549. [PMID: 16083711 DOI: 10.1053/j.gastro.2005.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
BACKGROUND & AIMS Germline mutations in mismatch repair genes are associated with hereditary nonpolyposis colorectal cancer. A significant proportion of mutations are nontruncating and associated with a variability of clinical phenotype and microsatellite instability and with occasional presence of residual protein in tumor tissue that suggests impaired functional activity but not total lack of mismatch repair. To address pathogenic significance and mechanism of pathogenicity, we studied the functionality of 31 nontruncating MLH1 mutations found in clinically characterized colorectal cancer families and 3 other variations listed in a mutation database. METHODS Mutations constructed by site-directed mutagenesis were studied for protein expression/stability, subcellular localization, protein-protein interaction, and repair efficiency. The genetic and biochemical data were correlated with clinical data. Finally, comparative sequence analysis was performed to assess the value of sequence homology as a tool for predicting functional results. RESULTS Altogether, 22 mutations were pathogenic in more than one assay, 2 variants were impaired in one assay, and 10 variants acted like wild-type protein. Twenty of 34 mutations affected the quantity of MLH1 protein, whereas only 15 mainly amino-terminal mutations were defective in an in vitro repair assay. Comparative sequence analysis correctly predicted functional studies for 82% of variants. CONCLUSIONS Pathogenic nontruncating alterations in MLH1 may interfere with different biochemical mechanisms but generally more than one. The severe biochemical defects are mirrored by phenotypic characteristics such as early age at onset and high microsatellite instability, whereas variants with no or mild defects in functionality are associated with variable clinical phenotypes.
Collapse
|