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Blasco RL, Strauss M, Velázquez López DA, Tabares S, Sembaj A, Rivarola HW, Paglini PA, Lo Presti MS. SCN5A gene variants as potential markers of the progression of chronic chagasic cardiac alterations. Parasitol Int 2020; 80:102213. [PMID: 33137501 DOI: 10.1016/j.parint.2020.102213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 08/03/2020] [Accepted: 08/10/2020] [Indexed: 11/19/2022]
Abstract
Host genetic factors have been proposed as determinants of the variable progression of Chagas disease (ChD). Two polymorphisms, H558R and A572D, of the voltage-gated sodium channel α-subunit SCN5A gene were studied in chagasic patients in order to determine their contribution to the susceptibility to the development and/or to the progression of the cardiovascular disease. A total of 104 patients were classified as seronegative or seropositive for Trypanosoma cruzi antibodies. Clinical evaluation, electrocardiograms (ECG) and echocardiograms (Echo) were performed to detect any conduction and/or structural alteration. Patients were classified into: G1: without ECG and/or Echo alterations, G2: with ECG alterations and G3: with ECG and Echo alterations. H558R and A572D polymorphisms were detected by PCR. Cardiac alterations were more frequent in G2 + G3 seropositive patients. For H558R polymorphism, the C allele was significantly increased in seropositive G2 + G3 patients (P = 0.049. OR = 2.08; 95% CI = 1.12-4.33). When comparing the disease cardiac progression (G2 vs G3), the genotypes from the H558R polymorphism were associated to more intense cardiac alterations (P = 0.018). For A572D polymorphism, no associations were found. The results suggest a possible involvement of SCN5A polymorphisms in the susceptibility to chronic ChD and the disease progression, contributing to the elucidation of the molecular mechanism underlying this complex myocardiopathy. In this regard, this is the first work that studies this gene in the context of chagasic cardiomyopathy.
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Affiliation(s)
- Romina Laura Blasco
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) UNC - CONICET, Centro de Estudios e Investigación de la Enfermedad de Chagas y Leishmaniasis, Cátedra de Física Biomédica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Mariana Strauss
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) UNC - CONICET, Centro de Estudios e Investigación de la Enfermedad de Chagas y Leishmaniasis, Cátedra de Física Biomédica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina.
| | - Daniela Alejandra Velázquez López
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) UNC - CONICET, Centro de Estudios e Investigación de la Enfermedad de Chagas y Leishmaniasis, Cátedra de Física Biomédica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Sandra Tabares
- Cátedra de Bioquímica y Biología Molecular, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Adela Sembaj
- Cátedra de Bioquímica y Biología Molecular, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Héctor Walter Rivarola
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) UNC - CONICET, Centro de Estudios e Investigación de la Enfermedad de Chagas y Leishmaniasis, Cátedra de Física Biomédica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - Patricia Adriana Paglini
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) UNC - CONICET, Centro de Estudios e Investigación de la Enfermedad de Chagas y Leishmaniasis, Cátedra de Física Biomédica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina
| | - María Silvina Lo Presti
- Instituto de Investigaciones en Ciencias de la Salud (INICSA) UNC - CONICET, Centro de Estudios e Investigación de la Enfermedad de Chagas y Leishmaniasis, Cátedra de Física Biomédica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina.
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2
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Allyn-Feuer A, Ade A, Luzum JA, Higgins GA, Athey BD. The pharmacoepigenomics informatics pipeline defines a pathway of novel and known warfarin pharmacogenomics variants. Pharmacogenomics 2018; 19:413-434. [PMID: 29400612 PMCID: PMC6021929 DOI: 10.2217/pgs-2017-0186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/16/2018] [Indexed: 12/21/2022] Open
Abstract
AIM 'Pharmacoepigenomics' methods informed by omics datasets and pre-existing knowledge have yielded discoveries in neuropsychiatric pharmacogenomics. Now we evaluate the generality of these methods by discovering an extended warfarin pharmacogenomics pathway. MATERIALS & METHODS We developed the pharmacoepigenomics informatics pipeline, a scalable multi-omics variant screening pipeline for pharmacogenomics, and conducted an experiment in the genomics of warfarin. RESULTS We discovered known and novel pharmacogenomics variants and genes, both coding and regulatory, for warfarin response, including adverse events. Such genes and variants cluster in a warfarin response pathway consolidating known and novel warfarin response variants and genes. CONCLUSION These results can inform a new warfarin test. The pharmacoepigenomics informatics pipeline may be able to discover new pharmacogenomics markers in other drug-disease systems.
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Affiliation(s)
- Ari Allyn-Feuer
- Department of Computational Medicine & Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Alex Ade
- Department of Computational Medicine & Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Jasmine A Luzum
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gerald A Higgins
- Department of Computational Medicine & Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Brian D Athey
- Department of Computational Medicine & Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, University of Michigan Health System, Ann Arbor, MI 48109, USA
- Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Michigan Institute for Data Science, University of Michigan Office of Research, Ann Arbor, MI 48109, USA
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3
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O'Rielly DD, Rahman P. Clinical genetic research 2: Genetic epidemiology of complex phenotypes. Methods Mol Biol 2015; 1281:349-67. [PMID: 25694321 DOI: 10.1007/978-1-4939-2428-8_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Genetic factors play a substantive role in the susceptibility to common diseases. Due to recent and rapid advancements in characterization of genetic variants and large-scale genotyping platforms, multiple genes and genetic variants have now been identified for common, complex diseases. The most efficient method for gene identification at present appears to be large-scale association-based studies, which integrate genetic and epidemiological principles. As the strategy for gene identification studies has shifted towards genetic association-based methods rather than traditional linkage analysis, epidemiological methods are increasingly being integrated into genetic investigations. Consequently, the disciplines of genetics and epidemiology, which historically have functioned separately, have been integrated into a discipline referred to as genetic epidemiology. In this chapter, we review methods for establishing the genetic burden of complex genetic disease, followed by methods for gene and/or genetic variant identification and when appropriate we highlight the epidemiological issues that guide these methods.
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Affiliation(s)
- Darren D O'Rielly
- Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
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TNF-α Gene Polymorphisms: Association with Disease Susceptibility and Response to Anti-TNF-α Treatment in Psoriatic Arthritis. J Invest Dermatol 2014; 134:2503-2509. [DOI: 10.1038/jid.2014.123] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 01/10/2014] [Accepted: 02/11/2014] [Indexed: 11/08/2022]
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5
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Johnston SE, Orell P, Pritchard VL, Kent MP, Lien S, Niemelä E, Erkinaro J, Primmer CR. Genome-wide SNP analysis reveals a genetic basis for sea-age variation in a wild population of Atlantic salmon (Salmo salar). Mol Ecol 2014; 23:3452-68. [DOI: 10.1111/mec.12832] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 06/04/2014] [Accepted: 06/06/2014] [Indexed: 12/17/2022]
Affiliation(s)
- Susan E. Johnston
- Division of Genetics and Physiology; Department of Biology; University of Turku; Itäinen Pitkäkatu 4 Turku FIN-20520 Finland
| | - Panu Orell
- Finnish Game and Fisheries Research Institute; Utsjoki FIN-99980 Finland
| | - Victoria L. Pritchard
- Division of Genetics and Physiology; Department of Biology; University of Turku; Itäinen Pitkäkatu 4 Turku FIN-20520 Finland
| | - Matthew P. Kent
- Centre for Integrative Genetics (CIGENE) and Department of Animal and Aquacultural Sciences; Norwegian University of Life Sciences; Aas N-1432 Norway
| | - Sigbjørn Lien
- Centre for Integrative Genetics (CIGENE) and Department of Animal and Aquacultural Sciences; Norwegian University of Life Sciences; Aas N-1432 Norway
| | - Eero Niemelä
- Finnish Game and Fisheries Research Institute; Utsjoki FIN-99980 Finland
| | - Jaakko Erkinaro
- Finnish Game and Fisheries Research Institute; Utsjoki FIN-99980 Finland
| | - Craig R. Primmer
- Division of Genetics and Physiology; Department of Biology; University of Turku; Itäinen Pitkäkatu 4 Turku FIN-20520 Finland
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Aljasir B, Ioannidis JPA, Yurkiewich A, Moher D, Higgins JPT, Arora P, Little J. Assessment of systematic effects of methodological characteristics on candidate genetic associations. Hum Genet 2013; 132:167-78. [PMID: 23095857 DOI: 10.1007/s00439-012-1237-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 10/08/2012] [Indexed: 12/30/2022]
Abstract
Candidate genetic association studies have been found to have a low replication rate in the past. Here, we aimed to assess whether aspects of reported methodological characteristics in genetic association studies may be related to the magnitude of effects observed. An observational, literature-based investigation of 511 case-control studies of genetic association studies indexed in 2007, was undertaken. Meta-regression analyses were used to assess the relationship between 23 reported methodological characteristics and the magnitude of genetic associations. The 511 studies had been conducted in 52 countries and were published in 220 journals (median impact factor 5.1). The multivariate meta-regression model of methodological characteristics plus disease category accounted for 17.2 % of the between-study variance in the magnitude of the reported genetic associations. Our findings are consistent with the view that better conducted and better reported genetic association research may lead to less inflated results.
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Affiliation(s)
- Badr Aljasir
- Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, ON, Canada
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Plenge RM, Bridges SL, Huizinga TWJ, Criswell LA, Gregersen PK. Recommendations for publication of genetic association studies in Arthritis & Rheumatism. ACTA ACUST UNITED AC 2013; 63:2839-47. [PMID: 21702018 DOI: 10.1002/art.30509] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Robert M Plenge
- Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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8
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Abstract
Genetic association studies explore the association between genetic polymorphisms and a certain trait, disease or predisposition to disease. It has long been acknowledged that many genetic association studies fail to replicate their initial positive findings. This raises concern about the methodological quality of these reports. Case-control genetic association studies often suffer from various methodological flaws in study design and data analysis, and are often reported poorly. Flawed methodology and poor reporting leads to distorted results and incorrect conclusions. Many journals have adopted guidelines for reporting genetic association studies. In this review, some major methodological determinants of genetic association studies will be discussed.
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Affiliation(s)
- Ana-Maria Simundic
- University Department of Chemistry, University Hospital "SESTRE MILOSRDNICE", Zagreb, Croatia.
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9
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Little J, Higgins JPT, Ioannidis JPA, Moher D, Gagnon F, von Elm E, Khoury MJ, Cohen B, Davey-Smith G, Grimshaw J, Scheet P, Gwinn M, Williamson RE, Zou GY, Hutchings K, Johnson CY, Tait V, Wiens M, Golding J, van Duijn C, McLaughlin J, Paterson A, Wells G, Fortier I, Freedman M, Zecevic M, King R, Infante-Rivard C, Stewart A, Birkett N. STrengthening the REporting of Genetic Association Studies (STREGA)--an extension of the STROBE statement. Genet Epidemiol 2010; 33:581-98. [PMID: 19278015 DOI: 10.1002/gepi.20410] [Citation(s) in RCA: 185] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the STrengthening the Reporting of OBservational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modelling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis.
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Affiliation(s)
- Julian Little
- Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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10
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de Menthon M, Lavalley MP, Maldini C, Guillevin L, Mahr A. HLA-B51/B5 and the risk of Behçet's disease: a systematic review and meta-analysis of case-control genetic association studies. ACTA ACUST UNITED AC 2009; 61:1287-96. [PMID: 19790126 DOI: 10.1002/art.24642] [Citation(s) in RCA: 297] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE To quantify by meta-analysis the genetic effect of the HLA-B5 or HLA-B51 (HLA-B51/B5) allele on the risk of developing Behçet's disease (BD) and to look for potential effect modifiers. METHODS Relevant studies were identified using the PubMed Medline database and manual searches of the literature. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated by using the random-effects model. Subgroup meta-analyses and meta-regression analyses were undertaken to investigate the effects of selected study-level parameters on the pooled OR. Heterogeneity was assessed using the I2 statistic. Pooled results were used to calculate population-attributable risks (PAR) for BD in relationship to HLA-B51/B5. RESULTS A total of 4,800 patients with BD and 16,289 controls from 78 independent studies (published 1975-2007) were selected. The pooled OR of HLA-B51/B5 allele carriers to develop BD compared with noncarriers was 5.78 (95% CI 5.00-6.67), with moderate between-study heterogeneity (I2 = 61%). The subgroup analyses stratifying studies by geographic locations (Eastern Asia, Middle East/North Africa, Southern Europe, Northern/Eastern Europe) yielded consistent OR ranges (5.31-7.20), with I2 ranges of 52-70%. Univariate random-effects meta-regression indicated the percentage of male BD cases (P = 0.008) as a source of heterogeneity. The PAR within the various geographic areas were estimated at 32-52%. CONCLUSION The strength of the association between BD and HLA-B51/B5, and its consistency across populations of various ethnicities, lends further support to this allele being a primary and causal risk determinant for BD. Variations according to sex support an interaction of this allele with BD characteristics.
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Affiliation(s)
- Mathilde de Menthon
- Hôpital Cochin; Université Paris-René Descartes, Assistance Publique Hôpitaux de Paris, Paris, France
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11
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Peters SP. Reporting and evaluating genetic association studies. Respir Res 2009; 10:109. [PMID: 19909535 PMCID: PMC2780405 DOI: 10.1186/1465-9921-10-109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 11/12/2009] [Indexed: 11/29/2022] Open
Abstract
Genetic association studies have become an important part of our scientific landscape. This commentary discusses some basic scientific issues which should be considered when reporting and evaluating such studies including SNP Discovery, Genotyping and Haplotype Analysis; Population Size, Matching of Cases and Controls, and Population Stratification; Phenotype Definition and Multiple Related Phenotypes; Multiple Testing; Replication; Genome-wide Association Studies (GWAS); and the Role of Functional Studies. All of these elements are important in evaluating such studies and should be carefully considered when these studies are conceived and carried out.
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Affiliation(s)
- Stephen P Peters
- Wake Forest University Health Sciences, Center for Human Genomics, Winston-Salem, NC, USA.
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12
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Little J, Higgins JP, Ioannidis JP, Moher D, Gagnon F, von Elm E, Khoury MJ, Cohen B, Davey-Smith G, Grimshaw J, Scheet P, Gwinn M, Williamson RE, Zou GY, Hutchings K, Johnson CY, Tait V, Wiens M, Golding J, van Duijn C, McLaughlin J, Paterson A, Wells G, Fortier I, Freedman M, Zecevic M, King R, Infante-Rivard C, Stewart AF, Birkett N. Strengthening the reporting of genetic association studies (STREGA)—an extension of the strengthening the reporting of observational studies in epidemiology (STROBE) statement. J Clin Epidemiol 2009; 62:597-608.e4. [DOI: 10.1016/j.jclinepi.2008.12.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 12/29/2008] [Accepted: 12/29/2008] [Indexed: 01/15/2023]
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13
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Little J, Higgins JPT, Ioannidis JPA, Moher D, Gagnon F, von Elm E, Khoury MJ, Cohen B, Davey-Smith G, Grimshaw J, Scheet P, Gwinn M, Williamson RE, Zou GY, Hutchings K, Johnson CY, Tait V, Wiens M, Golding J, van Duijn C, McLaughlin J, Paterson A, Wells G, Fortier I, Freedman M, Zecevic M, King R, Infante-Rivard C, Stewart A, Birkett N. STrengthening the REporting of Genetic Association studies (STREGA)--an extension of the STROBE statement. Eur J Clin Invest 2009; 39:247-66. [PMID: 19297801 PMCID: PMC2730482 DOI: 10.1111/j.1365-2362.2009.02125.x] [Citation(s) in RCA: 183] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the STrengthening the Reporting of OBservational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modelling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed, but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct or analysis.
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Affiliation(s)
- Julian Little
- Canada Research Chair in Human Genome Epidemiology, Ottawa, ON, Canada.
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14
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Little J, Higgins JPT, Ioannidis JPA, Moher D, Gagnon F, von Elm E, Khoury MJ, Cohen B, Davey-Smith G, Grimshaw J, Scheet P, Gwinn M, Williamson RE, Zou GY, Hutchings K, Johnson CY, Tait V, Wiens M, Golding J, van Duijn C, McLaughlin J, Paterson A, Wells G, Fortier I, Freedman M, Zecevic M, King R, Infante-Rivard C, Stewart A, Birkett N. STrengthening the REporting of Genetic Association Studies (STREGA): an extension of the STROBE statement. PLoS Med 2009; 6:e22. [PMID: 19192942 PMCID: PMC2634792 DOI: 10.1371/journal.pmed.1000022] [Citation(s) in RCA: 315] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modelling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis.
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Affiliation(s)
- Julian Little
- Canada Research Chair in Human Genome Epidemiology, University of Ottawa, Ottawa, Ontario, Canada.
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15
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Little J, Higgins JPT, Ioannidis JPA, Moher D, Gagnon F, von Elm E, Khoury MJ, Cohen B, Davey-Smith G, Grimshaw J, Scheet P, Gwinn M, Williamson RE, Zou GY, Hutchings K, Johnson CY, Tait V, Wiens M, Golding J, van Duijn C, McLaughlin J, Paterson A, Wells G, Fortier I, Freedman M, Zecevic M, King R, Infante-Rivard C, Stewart A, Birkett N. Strengthening the reporting of genetic association studies (STREGA): an extension of the STROBE statement. Eur J Epidemiol 2009; 24:37-55. [PMID: 19189221 PMCID: PMC2764094 DOI: 10.1007/s10654-008-9302-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2008] [Accepted: 11/04/2008] [Indexed: 02/02/2023]
Abstract
Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modeling haplotype variation, Hardy–Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis.
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Affiliation(s)
- Julian Little
- Canada Research Chair in Human Genome Epidemiology, Toronto, ON, Canada.
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Little J, Higgins JPT, Ioannidis JPA, Moher D, Gagnon F, von Elm E, Khoury MJ, Cohen B, Davey-Smith G, Grimshaw J, Scheet P, Gwinn M, Williamson RE, Zou GY, Hutchings K, Johnson CY, Tait V, Wiens M, Golding J, van Duijn C, McLaughlin J, Paterson A, Wells G, Fortier I, Freedman M, Zecevic M, King R, Infante-Rivard C, Stewart A, Birkett N. Strengthening the reporting of genetic association studies (STREGA): an extension of the STROBE Statement. Hum Genet 2009; 125:131-51. [DOI: 10.1007/s00439-008-0592-7] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Accepted: 11/09/2008] [Indexed: 12/21/2022]
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Simundic AM, Nikolac N, Topic E. Methodological Issues in Genetic Association Studies of Inherited Thrombophilia: Original Report of Recent Practice. Clin Appl Thromb Hemost 2008; 15:327-33. [DOI: 10.1177/1076029608315162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The aims of this article are to evaluate the methodological quality of genetic association studies on the inherited thrombophilia published during 2003 to 2005, to identify the most common mistakes made by authors of those studies, and to examine if overall quality of the article correlates with the quality of the journal. Articles were evaluated by 2 independent reviewers using the checklist of 16 items. A total of 58 eligible studies were identified. Average total score was 7.59 ± 1.96. Total article score did not correlate with the journal impact factor (r = 0.3971; 95% confidence interval [CI], 0.1547-0.5944, P = .002). Total score did not differ across years ( P = .624). Finally, it is concluded that methodological quality of genetic association studies is not optimal, and it does not depend on the quality of the journal. Journals should adopt methodological criteria for reporting the genetic association studies, and editors should encourage authors to strictly adhere to those criteria.
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Affiliation(s)
- Ana-Maria Simundic
- Clinical Institute of Chemistry, Sestre milosrdnice University Hospital, Zagreb, Croatia, am.simundic@ gmail.com
| | - Nora Nikolac
- Clinical Institute of Chemistry, Sestre milosrdnice University Hospital, Zagreb, Croatia
| | - Elizabeta Topic
- Clinical Institute of Chemistry, Sestre milosrdnice University Hospital, Zagreb, Croatia
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Abstract
Genetic factors play a substantive role in the susceptibility to common diseases. Due to recent advancements in the characterization of genetic variants and large-scale genotyping platforms, multiple genes have now been identified for common, complex diseases. As a result, there is an immense interest in elucidating genetic factors in complex traits. Therefore, it is important to understand the design as well as the technical and statistical issues of the two most common approaches for gene identification: linkage and association.
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van der Straaten RJHM, Wessels JAM, de Vries-Bouwstra JK, Goekoop-Ruiterman YPM, Allaart CF, Bogaartz J, Tiller M, Huizinga TWJ, Guchelaar HJ. Exploratory analysis of four polymorphisms in human GGH and FPGS genes and their effect in methotrexate-treated rheumatoid arthritis patients. Pharmacogenomics 2007; 8:141-50. [PMID: 17286537 DOI: 10.2217/14622416.8.2.141] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The enzyme folylpoly-gamma-glutamase synthethase (FPGS) plays an important role in the intracellular polyglutamation of the disease-modifying antirheumatic drug methotrexate (MTX) and the length of the polyglutamated MTX product correlates with the time that MTX resides in the cell. The glutamates are released from MTX by activity of the enzyme gamma-glutamyl-hydrolase (GGH), thereby allowing the efflux of MTX. GGH 452C>T has been associated with decreased catalytic activity and higher accumulation of long-chain MTX-polyglutamate. However, single nucleotide polymorphisms (SNPs) in FPGS and GGH genes have not yet been explored for association with MTX efficacy or toxicity. We selected for SNPs with frequencies higher than 10% or, in case of FPGS 114G>A, causing an amino acid change with no known frequencies. In this study, frequencies of two SNPs in FPGS (1994A>G and 114G>A, rs10106 and rs10760502, respectively) and GGH genes (452C>T and 16T>C, rs11545078 and rs1800909, respectively), were determined using a newly developed method in rheumatoid arthritis patients (n = 352) and in a group of healthy controls (n = 360). Next, the SNPs were associated with response to MTX in rheumatoid arthritis patients treated with MTX monotherapy. In rheumatoid arthritis patients, allele frequencies of FPGS 1994A>G were 0.534 (A) and 0.466 (G), and for FPGS 114G>A 0.714 (G) and 0.286 (A). Allele frequencies of GGH 16T>C were 0.737 (T) and 0.263 (C) and for GGH 452C>T 0.912 (C) and 0.088 (T). No significant differences in allele frequencies between rheumatoid arthritis patients and healthy controls were found. In addition, the SNPs were not associated with good clinical response to MTX. Only patients with the GGH 16C-allele and one or no copies of the GGH 452C-16T haplotype were associated with good clinical improvement at 3 months upon treatment with MTX. No associations with efficacy at 6 months and MTX-induced toxicity were found. Therefore we conclude that despite the positive association of the GGH 16C-allele and one or no copies of the GGH 452C-16T haplotype with good clinical improvement at 3 months upon treatment with MTX, the tested SNPs in GGH and FPGS genes are suggested not to be clinically important for MTX treatment outcome.
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Affiliation(s)
- R J H M van der Straaten
- Leiden University Medical Center, Department of Clinical Pharmacy and Toxicology, P.O. Box 9600, 2300 RA Leiden, The Netherlands.
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20
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Vaglio A, Martorana D, Maggiore U, Grasselli C, Zanetti A, Pesci A, Garini G, Manganelli P, Bottero P, Tumiati B, Sinico RA, Savi M, Buzio C, Neri TM. HLA-DRB4 as a genetic risk factor for Churg-Strauss syndrome. ACTA ACUST UNITED AC 2007; 56:3159-66. [PMID: 17763415 DOI: 10.1002/art.22834] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To explore the association between HLA alleles and Churg-Strauss syndrome (CSS), and to investigate the potential influence of HLA alleles on the clinical spectrum of the disease. METHODS Low-resolution genotyping of HLA-A, HLA-B, and HLA-DR loci and genotyping of TNFA -238A/G and TNFA -308A/G single-nucleotide polymorphisms were performed in 48 consecutive CSS patients and 350 healthy controls. RESULTS The frequency of the HLA-DRB1*07 allele was higher in the CSS patients than in controls (27.1% versus 13.3%; chi(2) = 12.64, P = 0.0003, corrected P [P(corr)] = 0.0042, odds ratio [OR] 2.42, 95% confidence interval [95% CI] 1.47-3.99). The HLA-DRB4 gene, present in subjects carrying either HLA-DRB1*04, HLA-DRB1*07, or HLA-DRB1*09 alleles, was also far more frequent in patients than in controls (38.5% versus 20.1%; chi(2) = 16.46, P = 0.000058, P(corr) = 0.000232, OR 2.49, 95% CI 1.58-3.09). Conversely, the frequency of the HLA-DRB3 gene was lower in patients than in controls (35.4% versus 50.4%; chi(2) = 7.62, P = 0.0057, P(corr) = 0.0228, OR 0.54, 95% CI 0.35-0.84). CSS has 2 major clinical subsets, antineutrophil cytoplasmic antibody (ANCA)-positive, with features of small-vessel vasculitis, and ANCA-negative, in which organ damage is mainly mediated by tissue eosinophilic infiltration; analysis of HLA-DRB4 in patients categorized by different numbers of vasculitic manifestations (purpura, alveolar hemorrhage, mononeuritis multiplex, rapidly progressive glomerulonephritis, and constitutional symptoms) showed that its frequency strongly correlated with the number of vasculitis symptoms (P for trend = 0.001). CONCLUSION These findings indicate that HLA-DRB4 is a genetic risk factor for the development of CSS and increases the likelihood of development of vasculitic manifestations of the disease.
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Abstract
Substantive evidence exists that genetic factors play a pivotal role in susceptibility to ankylosing spondylitis (AS). HLA-B27 remains the most convincing and universal association of a genetic factor with AS. Over the last decade there has been immense interest in elucidating genetic variants outside the major histocompatibility complex region. Due to larger AS datasets along with recent advancements in the characterization of genetic markers and large-scale genotyping platforms, replicated non-major histocompatibility candidates have now emerged. This article reviews the current evidence regarding the genetics of AS, with an emphasis on the recent major advances, and it discusses the challenges and limitations in interpreting these studies.
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Affiliation(s)
- Proton Rahman
- 154 Le Marchant Road, St. Clare's Mercy Hospital, St. John's, NL, A1C-5B8, Canada.
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22
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Ioannidis JPA, Boffetta P, Little J, O'Brien TR, Uitterlinden AG, Vineis P, Balding DJ, Chokkalingam A, Dolan SM, Flanders WD, Higgins JPT, McCarthy MI, McDermott DH, Page GP, Rebbeck TR, Seminara D, Khoury MJ. Assessment of cumulative evidence on genetic associations: interim guidelines. Int J Epidemiol 2007; 37:120-32. [PMID: 17898028 DOI: 10.1093/ije/dym159] [Citation(s) in RCA: 442] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Established guidelines for causal inference in epidemiological studies may be inappropriate for genetic associations. A consensus process was used to develop guidance criteria for assessing cumulative epidemiologic evidence in genetic associations. A proposed semi-quantitative index assigns three levels for the amount of evidence, extent of replication, and protection from bias, and also generates a composite assessment of 'strong', 'moderate' or 'weak' epidemiological credibility. In addition, we discuss how additional input and guidance can be derived from biological data. Future empirical research and consensus development are needed to develop an integrated model for combining epidemiological and biological evidence in the rapidly evolving field of investigation of genetic factors.
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Affiliation(s)
- John P A Ioannidis
- Clinical and Molecular Epidemiology Unit, University of Ioannina School of Medicine, Ioannina 45110, Greece.
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23
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Wessels JAM, van der Kooij SM, le Cessie S, Kievit W, Barerra P, Allaart CF, Huizinga TWJ, Guchelaar HJ. A clinical pharmacogenetic model to predict the efficacy of methotrexate monotherapy in recent-onset rheumatoid arthritis. ACTA ACUST UNITED AC 2007; 56:1765-75. [PMID: 17530705 DOI: 10.1002/art.22640] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE To develop a clinical pharmacogenetic model to predict the efficacy of methotrexate (MTX) in rheumatoid arthritis (RA). METHODS Two hundred five patients with newly diagnosed RA and active disease were treated with MTX (initiated at a dosage of 7.5 mg/week and increased to 15 mg/week after 4 weeks) and folic acid (1 mg/day). If the Disease Activity Score (DAS) was >2.4 at 3 months, the dosage of MTX was increased up to 25 mg/week. Twenty-four baseline variables possibly influencing disease state and drug response were selected. In addition, 17 polymorphisms in 13 genes related to the MTX mechanism of action, purine and pyrimidine synthesis, were determined. Factors were compared between responders (defined as patients with a DAS < or = 2.4 at 6 months) and nonresponders. In case of differences, a stepwise selection procedure identified the predictors for response. A clinical score was designed by simplifying regression coefficients of the independent variables. Cutoff levels were chosen based on the clinical score, and positive and negative response rates were calculated. An evaluation of the model was performed in a second group of patients. RESULTS The model for MTX efficacy consisted of sex, rheumatoid factor and smoking status, the DAS, and 4 polymorphisms in the AMPD1, ATIC, ITPA, and MTHFD1 genes. This prediction model was transformed into a scoring system ranging from 0 to 11.5. Scores of < or = 3.5 had a true positive response rate of 95%. Scores of > or = 6 had a true negative response rate of 86%. Sixty percent of the patients were categorized as either responders or nonresponders, whereas 32% of the patients were categorized using a nongenetic model. Evaluation of the model in 38 additional patients with RA supported the results. CONCLUSION This study established a model for predicting the efficacy of MTX in patients with RA. This pharmacogenetic model may lead to better-tailored initial treatment decisions in patients with RA.
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Rebbeck TR, Khoury MJ, Potter JD. Genetic Association Studies of Cancer: Where Do We Go from Here? Cancer Epidemiol Biomarkers Prev 2007; 16:864-5. [PMID: 17507606 DOI: 10.1158/1055-9965.epi-07-0289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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25
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Affiliation(s)
- P H Reitsma
- Einthoven Laboratory for Experimental Vascular Medicine, Departments of Hematology and Nephrology, Leiden University Medical Center, Leiden, the Netherlands
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26
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Kooloos WM, de Jong DJ, Huizinga TWJ, Guchelaar HJ. Potential role of pharmacogenetics in anti-TNF treatment of rheumatoid arthritis and Crohn's disease. Drug Discov Today 2006; 12:125-31. [PMID: 17275732 DOI: 10.1016/j.drudis.2006.11.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Revised: 11/09/2006] [Accepted: 11/23/2006] [Indexed: 12/20/2022]
Abstract
Etanercept, infliximab and adalimumab have shown clinical benefit in immune-mediated inflammatory diseases; however, the outcome of treatment with these tumour-necrosis factor inhibitors remains insufficient in approximately 40-60% and approximately 25-40% of individuals with rheumatoid arthritis and Crohn's disease, respectively. Moreover, their use is accompanied by adverse events and unintentional immune suppression. Pharmacogenetics has the potential to increase efficacy and ameliorate adverse events and immune suppression, and its application might be of clinical benefit for patients with rheumatoid arthritis and Crohn's disease. Pharmacogenetic studies have shown associations between single nucleotide polymorphisms in genes encoding enzymes related to the pharmacodynamics of these drugs and treatment outcome. As we discuss here, replication and prospective validation are warranted before pharmacogenetics can be used in clinical practice.
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Affiliation(s)
- Wouter M Kooloos
- Department of Clinical Pharmacy & Toxicology, Leiden University Medical Center, PO Box 9600, NL 2300 RC Leiden, The Netherlands
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Wessels JAM, Kooloos WM, De Jonge R, De Vries-Bouwstra JK, Allaart CF, Linssen A, Collee G, De Sonnaville P, Lindemans J, Huizinga TWJ, Guchelaar HJ. Relationship between genetic variants in the adenosine pathway and outcome of methotrexate treatment in patients with recent-onset rheumatoid arthritis. ACTA ACUST UNITED AC 2006; 54:2830-9. [PMID: 16947783 DOI: 10.1002/art.22032] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Among patients with rheumatoid arthritis (RA), there is a high degree of interindividual variability in the degree of response to methotrexate (MTX) treatment. This study was undertaken to explore polymorphisms in genes contributing to antiinflammatory adenosine release as novel predictors of MTX treatment outcome. METHODS In 205 patients with newly diagnosed RA, 5 polymorphisms in 5 genes coding for enzymes related to the release of adenosine were analyzed. All patients received standardized MTX treatment (up to 25 mg per week orally), combined with folic acid. MTX efficacy was evaluated by the Disease Activity Score (DAS) and compared among genotypes. The association between MTX-related adverse events and genotype was also assessed. The following polymorphisms were determined: AMPD1 34C>T, ATIC 347C>G, ITPA 94C>A, MTR 2756A>G, and MTRR 66A>G. When significant differences were found by chi-square analysis, odds ratios (ORs) and 95% confidence intervals were calculated. RESULTS Patients carrying the AMPD1 34T allele, ATIC 347CC, or ITPA 94CC were more likely to have a good clinical response, as defined by a DAS of < or =2.4 (OR [95% confidence interval] 2.1 [1.0-4.5], 2.5 [1.3-4.7], and 2.7 [1.1-8.1], respectively). The likelihood of a good clinical response was increased if patients possessed all 3 favorable genotypes (OR 27.8 [95% confidence interval 3.2-250]). Regarding toxicity, only ATIC G allele carriers experienced a greater frequency of adverse events (OR 2.0 [95% confidence interval 1.1-3.7]). CONCLUSION Polymorphisms in the AMPD1, ATIC, and ITPA genes are associated with good clinical response to MTX treatment. These findings indicate that genotyping may help in the identification of patients who will benefit most from MTX treatment and may assist clinicians in making treatment decisions regarding patients with recent-onset RA.
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Orozco G, Rueda B, Martin J. Genetic basis of rheumatoid arthritis. Biomed Pharmacother 2006; 60:656-62. [PMID: 17055211 DOI: 10.1016/j.biopha.2006.09.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 09/21/2006] [Indexed: 12/20/2022] Open
Abstract
Rheumatoid arthritis (RA) is a clinically heterogeneous condition with a complex aetiology in which environmental and genetic factors are implicated. The contribution of human leukocyte antigen (HLA) genes, particularly the HLA-DRB1 gene, to RA genetic predisposition was the first described, and remains as the best characterised single genetic risk factor contributing to RA. However, it has been estimated that only 30% of the genetic contribution to RA can be attributed to HLA genes and it is suggested that other non-HLA genes may play a relevant role in RA susceptibility. Linkage studies and association studies are the two main strategies used in the investigation of genetic factors contributing to complex genetic traits. In this work we review the progress made in the field of RA genetics, focusing mainly on the contribution of candidate gene association studies to the dissection of RA genetic risk factors.
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Affiliation(s)
- G Orozco
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento s/n 18100 Armilla, Granada, Spain
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Liu YJ, Shen H, Xiao P, Xiong DH, Li LH, Recker RR, Deng HW. Molecular genetic studies of gene identification for osteoporosis: a 2004 update. J Bone Miner Res 2006; 21:1511-35. [PMID: 16995806 PMCID: PMC1829484 DOI: 10.1359/jbmr.051002] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This review summarizes comprehensively the most important and representative molecular genetics studies of gene identification for osteoporosis published up to the end of December 2004. It is intended to constitute a sequential update of our previously published review covering the available data up to the end of 2002. Evidence from candidate gene association studies and genome-wide linkage studies in humans, as well as quantitative trait locus mapping animal models are reviewed separately. Studies of transgenic and knockout mice models relevant to osteoporosis are summarized. An important extension of this update is incorporation of functional genomic studies (including DNA microarrays and proteomics) on osteogenesis and osteoporosis, in light of the rapid advances and the promising prospects of the field. Comments are made on the most notable findings and representative studies for their potential influence and implications on our present understanding of genetics of osteoporosis. The format adopted by this review should be ideal for accommodating future new advances and studies.
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Affiliation(s)
- Yong-Jun Liu
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Hui Shen
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Peng Xiao
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Dong-Hai Xiong
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Li-Hua Li
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Robert R Recker
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
| | - Hong-Wen Deng
- Osteoporosis Research Center, Creighton University Medical Center, Omaha, Nebraska, USA
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, China
- Laboratory of Molecular and Statistical Genetics, College of Life Sciences Hunan Normal University, Changsha, Hunan, China
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30
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Clements DN, Carter SD, Innes JF, Ollier WER. Genetic basis of secondary osteoarthritis in dogs with joint dysplasia. Am J Vet Res 2006; 67:909-18. [PMID: 16649929 DOI: 10.2460/ajvr.67.5.909] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Dylan N Clements
- Connective Tissue Research Group, Faculty of Veterinary Science, University of Liverpool, Liverpool, L69 3BX, UK
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31
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Marotte H, Tournoud M, Cazalis MA, Mougin B, Roy P, Miossec P. Extensive multiallelic analysis of the relationship between HLA-DRB1 and rheumatoid arthritis using a Bayesian partition model. Genes Immun 2006; 7:487-93. [PMID: 16826237 DOI: 10.1038/sj.gene.6364319] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To analyse the association between individual HLA-DRB1 locus genotypes and rheumatoid arthritis (RA) susceptibility, taking in account the multiallelic nature of the shared epitope (SE). In total, 538 patients and 536 controls were genotyped for 12 alleles of the HLA-DRB1 locus. A Bayesian partition model and multivariate logistic models were used to assess the role of the SE and of its individual components. The SE was associated with RA susceptibility (odds ratio (OR) 2 versus 0 SE copy=9.99 (95 CI 4.69-15.30) and OR 1 versus 0 SE copy=3.16 (95% CI 2.42-4.12)). The Bayesian partition model supplied a permutation of the HLA-DRBA locus alleles ordered by increasing disease risk. Alleles associated with highest risks are those that code for the SE. The individual OR estimations for the HLA-DRB1 locus genotypes went from OR=1.00 (95% CI 1.00-1.25) for the less associated genotype to OR=21.40 (95% CI 8.02-65.79) for the most associated one. In conclusion, the allele order risk and the OR estimations for individual genotypes of the HLA-DRB1 locus were consistent with the SE theory. Using an exploratory statistical method without a priori hypothesis, our study allowed a detailed analysis of the multiallelic nature of the SE.
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Affiliation(s)
- H Marotte
- 1Department of Immunology and Rheumatology, Unité Mixte Hospices Civils de Lyon - BioMérieux, Hôpital Edouard Herriot, Lyon Cedex, France
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Martorana D, Vaglio A, Greco P, Zanetti A, Moroni G, Salvarani C, Savi M, Buzio C, Neri TM. Chronic periaortitis and HLA-DRB1*03: another clue to an autoimmune origin. ACTA ACUST UNITED AC 2006; 55:126-30. [PMID: 16463424 DOI: 10.1002/art.21698] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Patients with chronic periaortitis (CP) often show clinical and laboratory findings of a systemic autoimmune disorder. The aim of the present study was to investigate the role of the HLA system in CP. METHODS Low-resolution genotyping for HLA-A, HLA-B, and HLA-DRB1 loci and genotyping of TNFA(-238)A/G and TNFA(-308)A/G single nucleotide polymorphisms were performed in 35 consecutive patients with CP and 350 healthy controls. RESULTS The HLA-DRB1*03 allele frequency was strikingly higher in patients with CP than in controls (24.28% versus 9.14%; chi(2) = 15.50, P = 0.000084, corrected P [P(corr)] = 0.0012, odds ratio [OR] 3.187, 95% confidence interval [95% CI] 1.74-5.83); the HLA-B*08 allele frequency was also higher in patients than in controls (17.14% versus 6.28%; chi(2)=11.12, P = 0.0008, P(corr) = 0.0269, OR 3.085, 95% CI 1.54-6.16). The A*01 allele frequency was significantly different (P = 0.0463), but the statistical significance was lost after correction for multiple testing (P(corr) = 0.5088). TNFA(-238)A allele and TNFA(-308)A allele frequencies were not significantly different (P = 0.512 and P = 0.445, respectively). Comparison of the main clinical and laboratory findings suggestive of a systemic autoimmune disease (e.g., acute-phase reactants, constitutional symptoms, other autoimmune diseases associated with CP) between the HLA-DRB1*03-positive and the HLA-DRB1*03-negative patients showed that the former group had significantly higher levels of C-reactive protein (P = 0.045) at disease onset, although this difference was not statistically significant after correction for multiple tests (P(corr) = 0.369). CONCLUSION The HLA system plays a role in susceptibility to CP. The strong association between CP and HLA-DRB1*03, an allele linked to a wide range of autoimmune conditions, further supports the view that CP may represent a clinical manifestation of an autoimmune disease.
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Affiliation(s)
- Davide Martorana
- Laboratory of Molecular Genetiucs, Dept. of Clinical Medicine, Nephrology and Health Science, University of Parma, Via Gramsci 14, 43100 Parma, Italy
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Saito YA, Talley NJ, de Andrade M, Petersen GM. Case-control genetic association studies in gastrointestinal disease: review and recommendations. Am J Gastroenterol 2006; 101:1379-89. [PMID: 16771964 DOI: 10.1111/j.1572-0241.2006.00587.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
As our knowledge of genetic variation grows, our ability to use this information to unravel the mysteries of human disease expands. Identification of genes and inexpensive methods to sequence them has resulted in a rising interest in evaluating specific variants and whether they may result in clinical manifestations or symptoms. Genetic variants include restriction fragment length polymorphisms, variable number tandem repeats, DNA microsatellites, and single nucleotide polymorphisms. Using these variants, genetic association studies, also referred to as candidate gene association or genotype-disease association studies are being performed by clinical and basic researchers alike. They are relatively easy to perform, but as a result of their deceivingly simple design, can be conducted or interpreted poorly. A positive association between a genotype and a GI disease of interest may be because the genotype causes (or increases susceptibility to) the disease, but may also be the result of the genotype being in linkage disequilibrium with the actual disease susceptibility gene, or be a false positive due to chance or bias in study design. An excellent understanding of the genetic and methodological issues surrounding these studies is therefore essential. We provide an overview of terminology and provide insight into the complexities underlying these studies. Recommendations for reporting the results of a genetic association study are provided to assist with study planning and manuscript preparation.
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Affiliation(s)
- Yuri A Saito
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota 55905, USA
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34
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Buchanan AV, Weiss KM, Fullerton SM. Dissecting complex disease: the quest for the Philosopher's Stone? Int J Epidemiol 2006; 35:562-71. [PMID: 16540539 DOI: 10.1093/ije/dyl001] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Is the search for the causes of complex disease akin to the alchemist's vain quest for the Philosopher's Stone? Complex chronic diseases have tremendous public health impact in the industrialized world. Much effort has been expended on research into their causes, with the aim of predicting who will be affected or preventing effects before they arise, but progress has been halting at best. In this paper, we discuss possible reasons including the use of models and methods that fit point-source and Mendelian diseases but may not be as appropriate for complex diseases, reliance on causal criteria that may not be as relevant as they are for communicable diseases, and the biology of complex disease itself. Finally, we ask whether most complex diseases are even good candidates for the kind of prediction and prevention that we have come to expect based on experience with infectious and Mendelian disease.
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Affiliation(s)
- Anne V Buchanan
- Department of Anthropology, Penn State University, University Park, PA 16802, USA
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35
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Ioannidis JPA, Gwinn M, Little J, Higgins JPT, Bernstein JL, Boffetta P, Bondy M, Bray MS, Brenchley PE, Buffler PA, Casas JP, Chokkalingam A, Danesh J, Smith GD, Dolan S, Duncan R, Gruis NA, Hartge P, Hashibe M, Hunter DJ, Jarvelin MR, Malmer B, Maraganore DM, Newton-Bishop JA, O'Brien TR, Petersen G, Riboli E, Salanti G, Seminara D, Smeeth L, Taioli E, Timpson N, Uitterlinden AG, Vineis P, Wareham N, Winn DM, Zimmern R, Khoury MJ. A road map for efficient and reliable human genome epidemiology. Nat Genet 2006; 38:3-5. [PMID: 16468121 DOI: 10.1038/ng0106-3] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Networks of investigators have begun sharing best practices, tools and methods for analysis of associations between genetic variation and common diseases. A Network of Investigator Networks has been set up to drive the process, sponsored by the Human Genome Epidemiology Network. A workshop is planned to develop consensus guidelines for reporting results of genetic association studies. Published literature databases will be integrated, and unpublished data, including 'negative' studies, will be captured by online journals and through investigator networks. Systematic reviews will be expanded to include more meta-analyses of individual-level data and prospective meta-analyses. Field synopses will offer regularly updated overviews.
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Affiliation(s)
- John P A Ioannidis
- Clinical and Molecular Epidemiology Unit, Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, and Biomedical Research Institute, Foundation for Research and Technology-Hellas, Ioannina 45110, Greece.
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Spector TD, Ahmadi KR, Valdes AM. When is a replication not a replication? Or how to spot a good genetic association study. ACTA ACUST UNITED AC 2006; 54:1051-4. [PMID: 16572439 DOI: 10.1002/art.21730] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Wessels JAM, de Vries-Bouwstra JK, Heijmans BT, Slagboom PE, Goekoop-Ruiterman YPM, Allaart CF, Kerstens PJSM, van Zeben D, Breedveld FC, Dijkmans BAC, Huizinga TWJ, Guchelaar HJ. Efficacy and toxicity of methotrexate in early rheumatoid arthritis are associated with single-nucleotide polymorphisms in genes coding for folate pathway enzymes. ACTA ACUST UNITED AC 2006; 54:1087-95. [PMID: 16572443 DOI: 10.1002/art.21726] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To determine associations of methotrexate (MTX) efficacy and toxicity with single-nucleotide polymorphisms (SNPs) in genes coding for folate pathway enzymes in patients with early rheumatoid arthritis (RA). METHODS Patients (n=205) with active RA received MTX at an initial dosage of 7.5 mg/week, which was increased to 15 mg/week and combined with folic acid (1 mg/day) after 4 weeks. If the Disease Activity Score in 44 joints (DAS44) was >2.4 at 3 months, MTX was increased to 25 mg/week. MTX efficacy was evaluated at 3 and 6 months and compared for genotypes in 3 analyses: patients with and without good response (DAS44<or=2.4), patients with and without good improvement (DeltaDAS44>1.2), and patients with and without moderate improvement (DeltaDAS44>0.6). The association between MTX-related adverse drug events (ADEs) and genotype was evaluated by comparing genotypes between patients with and without ADEs, specifically pneumonitis, gastrointestinal ADEs, skin and mucosal ADEs, and elevated liver enzyme levels. The following SNPs were analyzed: methylenetetrahydrofolate reductase (MTHFR) 677C>T, MTHFR 1298A>C, dihydrofolate reductase (DHFR) -473G>A, DHFR 35289G>A, and reduced folate carrier 80G>A. In case of significant differences, odds ratios (ORs) were calculated. RESULTS At 6 months, MTHFR 1298AA was associated with good improvement relative to 1298C (OR 2.3, 95% confidence interval [95% CI] 1.18-4.41), which increased with increased copies of the MTHFR 677CC haplotype. In contrast, MTHFR 1298C allele carriers developed more ADEs (OR 2.5, 95% CI 1.32-4.72). CONCLUSION Patients with MTHFR 1298AA and MTHFR 677CC showed greater clinical improvement with MTX, whereas only the MTHFR 1298C allele was associated with toxicity. In the future, MTHFR genotypes may help determine which patients will benefit most from MTX treatment.
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Affiliation(s)
- Judith A M Wessels
- Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands.
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Thornton S. Contribution of angiogenic genes to the complex genetic trait underlying Kawasaki disease. ACTA ACUST UNITED AC 2006; 54:1361-5. [PMID: 16645964 DOI: 10.1002/art.21810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Rahman P, Siannis F, Butt C, Farewell V, Peddle L, Pellett F, Gladman D. TNFalpha polymorphisms and risk of psoriatic arthritis. Ann Rheum Dis 2005; 65:919-23. [PMID: 16284098 PMCID: PMC1798211 DOI: 10.1136/ard.2005.039164] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Tumour necrosis factor alpha (TNFalpha) is a cytokine of critical importance in psoriatic arthritis. OBJECTIVES (1) To examine the association between TNFalpha promoter gene polymorphisms and psoriatic arthritis in two well characterised Canadian populations with the disease; (2) to carry out a meta-analysis of all TNFalpha association studies in white psoriatic arthritis populations. METHODS DNA samples were genotyped for five TNF variants by time of flight mass spectrometry using the Sequenom platform. All five single nucleotide polymorphisms were in the 5' flanking region of TNFalpha gene at the following positions: -1031 (T-->C), -863 (C-->A), -857 (C-->T), -308 (G-->A), and -238 (G-->A). Primary analyses were based on logistic regression. Summary estimates of disease/genotype relations from several studies were derived from random effects meta-analyses. RESULTS 237 psoriatic arthritis subjects and 103 controls from Newfoundland and 203 psoriatic arthritis subjects and 101 controls from Toronto were studied. A combined analysis of data from both populations, showed a significant association between disease status and the -238(A) variant (p=0.01). The meta-analysis estimate for the -238(A) TNFalpha variant in eight psoriatic arthritis populations was also significant (odds ratio=2.29 (95% confidence interval, 1.48 to 3.55)). CONCLUSIONS Analysis of TNFalpha variants in psoriatic arthritis populations shows that the -238 (A) variant is a significant risk factor for this disease.
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Affiliation(s)
- P Rahman
- St Clare's Mercy Hospital, Memorial University of Newfoundland, 1 South-154 LeMarchant Rd, St John's, Newfoundland, Canada A1C-5B8.
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Gomez LM, Anaya JM, Gonzalez CI, Pineda-Tamayo R, Otero W, Arango A, Martín J. PTPN22 C1858T polymorphism in Colombian patients with autoimmune diseases. Genes Immun 2005; 6:628-31. [PMID: 16163373 DOI: 10.1038/sj.gene.6364261] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A functional single nucleotide polymorphism (SNP) C1858T in the protein tyrosine phosphatase nonreceptor 22 (PTPN22) gene encoding an intracellular phosphatase with negative regulatory effects on T-cell activation is associated with some autoimmune diseases in Caucasians. Taking into account firstly, that SNP frequencies may vary across populations and, secondly, that replication studies are important to confirm previous associations, we examined the influence of PTPN22 polymorphism in 621 Colombian patients with four autoimmune diseases. Accordingly, 298 patients with rheumatoid arthritis (RA), 143 with systemic lupus erythematosus (SLE), 70 with primary Sjogren's syndrome (pSS) and 110 with Type 1 diabetes (T1D) were studied. The control group consisted of 308 matched healthy individuals. Genotyping of PTPN22 was performed by the real-time polymerase chain reaction technology, using the Taq Man 5'-allele discrimination assay. The 1858 T allele was found to be a risk factor for pSS (odds ratio (OR)=2.42), SLE (OR=2.56), and T1D (OR=1.83). A lower but nonsignificant trend was observed for RA (OR=1.26). These results confirm the influence of PTPN22 in autoimmunity and indicate that autoimmune phenotypes could represent pleiotropic outcomes of nonspecific disease genes that underlie similar immunogenetic mechanisms.
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Affiliation(s)
- L M Gomez
- Cellular Biology and Immunogenetics Unit (CBIU), Corporación para Investigaciones Biológicas (CIB) and Universidad de Antioquia, Medellin, Colombia, CSIC, Granada, Spain
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Maalej A, Petit-Teixeira E, Michou L, Rebai A, Cornelis F, Ayadi H. Association study of VDR gene with rheumatoid arthritis in the French population. Genes Immun 2005; 6:707-11. [PMID: 16151416 DOI: 10.1038/sj.gene.6364260] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Vitamin D is a potent regulator of calcium homeostasis and may have immunomodulatory effects. The influence of vitamin D on human autoimmune disease is controversial. The aim of this study was to investigate the role of vitamin D receptor gene (VDR) in rheumatoid arthritis (RA). Three polymorphisms for VDR gene FokI T>C (rs 10735810), BsmI A>G (rs 1544410) and TaqI C>T (rs 731236) were genotyped in 100 RA French nuclear families (set 1) and 100 additional French nuclear families for replication (set 2). The association analysis was performed using comparison of alleles frequencies (AFBAC), transmission disequilibrium test and genotype relative risk. Our results revealed a significant difference of F allele of FokI polymorphism between transmitted and nontransmitted frequencies (P=0.01) in set 1. Furthermore, the F/F genotype was more frequent in RA patients compared to controls (P=0.01) in set 1. The replication in set 2 showed similar patterns of transmission with a nonsignificant association. Association with FokI was found to be significant when the two sets were combined (P=0.006). These data suggest that the F allele and F/F VDR genotype are associated with RA. The mechanisms by which distinct receptor variants might confer disease susceptibility remain to be elucidated.
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Affiliation(s)
- A Maalej
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Avenue Majida Boulila, 3029 Sfax, Tunisia
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Ohmura K, Johnsen A, Ortiz-Lopez A, Desany P, Roy M, Besse W, Rogus J, Bogue M, Puech A, Lathrop M, Mathis D, Benoist C. Variation in IL-1beta gene expression is a major determinant of genetic differences in arthritis aggressivity in mice. Proc Natl Acad Sci U S A 2005; 102:12489-94. [PMID: 16113081 PMCID: PMC1194932 DOI: 10.1073/pnas.0504325102] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In humans and in animal models, susceptibility to arthritis is under complex genetic control, reflecting influences on the immunological processes that initiate autoimmunity and on subsequent inflammatory mechanisms in the joints. The effector phases are conveniently modeled by the K/BxN serum transfer system, a robust model well suited for genetic analysis where arthritis is initiated by pathogenic Ig. Here, we mapped the genetic loci distinguishing the high-responder BALB/c vs. low-responder SJL strains. After computational modeling of potential breeding schemes, we adapted a stepwise selective breeding strategy, with a whole-genome scan performed on a limited number of animals. Several genomic regions proved significantly associated with high sensitivity to arthritis. One of these regions, on distal chr2, was centered on the interleukin 1 gene family. Quantitation of transcripts of the Il1a and Il1b candidate genes revealed a 10-fold greater induction of Il1b mRNA in BALB/c than in SJL splenocytes after injection of LPS, whereas Il1a showed much less difference. The differential activity of the Il1b gene was associated with a particular sequence haplotype of noncoding polymorphisms. The BALB/c haplotype was found in 75% of wild-derived strains but was rare among conventional inbred strains (4/33 tested, one of which is DBA/1, the prototype arthritis-susceptible strain) and was associated with vigorous Il1b responses in a panel of inbred strains. Inbred strains carrying this allele were far more responsive to serum-transferred arthritis, confirming its broad importance in controlling arthritis severity.
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Affiliation(s)
- Koichiro Ohmura
- Sections on Immunology and Immunogenetics, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital; Harvard Medical School, Boston, MA 02215, USA
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Linn-Rasker SP, van der Helm-van Mil AHM, van Gaalen FA, Kloppenburg M, de Vries RRP, le Cessie S, Breedveld FC, Toes REM, Huizinga TWJ. Smoking is a risk factor for anti-CCP antibodies only in rheumatoid arthritis patients who carry HLA-DRB1 shared epitope alleles. Ann Rheum Dis 2005; 65:366-71. [PMID: 16014670 PMCID: PMC1798061 DOI: 10.1136/ard.2005.041079] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVES To study the gene-environment interaction of tobacco exposure and shared epitope on autoantibodies in patients with rheumatoid arthritis and undifferentiated arthritis. METHODS From incident cases of arthritis (n = 1305), patients who did not fulfil any classification criteria (undifferentiated arthritis (n = 486)) and those who fulfilled the American College of Rheumatology criteria for rheumatoid arthritis (n = 407) were identified. IgM rheumatoid factor (RF), anti-cyclic-citrullinated peptide (CCP) antibodies, and HLA-DRB1 alleles were determined. RESULTS In rheumatoid arthritis, an interaction was found between tobacco exposure and shared epitope for the presence of anti-CCP antibodies, as the odds ratio for anti-CCP antibodies in patients having both tobacco exposure (TE) and shared epitope (SE) was higher than the summed odds ratios of patients having only tobacco exposure or shared epitope (odds ratios: TE+/SE-, 1.07; TE-/SE+, 2.49; and TE+/SE+, 5.27-all relative to TE-/SE-). A similar effect was found for RF, but stratification showed that the interaction primarily associated with the anti-CCP antibody response. In patients with undifferentiated arthritis at two weeks, or with persistent undifferentiated arthritis after one year, no interaction between tobacco exposure and shared epitope was observed for the presence of autoantibodies. CONCLUSIONS Tobacco exposure increases the risk factor for anti-CCP antibodies only in shared epitope positive patients with rheumatoid arthritis. The gene-environment interaction between smoking and shared epitope leading to autoantibodies is specific for rheumatoid arthritis and is not observed in undifferentiated arthritis.
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Affiliation(s)
- S P Linn-Rasker
- Department of Rheumatology, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, Netherlands
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van der Helm-van Mil AHM, Wesoly JZ, Huizinga TWJ. Understanding the genetic contribution to rheumatoid arthritis. Curr Opin Rheumatol 2005; 17:299-304. [PMID: 15838240 DOI: 10.1097/01.bor.0000160780.13012.be] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW The identification of the genetic variants that mediate the risk for susceptibility and severity of rheumatoid arthritis will allow the development of new drug targets and also increase the ability to predict disease course. Technical and methodologic progress has fueled the advances in this field. RECENT FINDINGS The second risk factor for rheumatoid arthritis, the PTPN22 polymorphism, has been identified. This genetic variant regulates the threshold of T cell activation. Intriguingly, this variant is a risk factor for diabetes as well. Moreover, it has been shown that multiple genetic variants in one pathway (both in a transcription factor, RUNX-1, as in the transcription factor binding site of RUNX1 in the SLC22A4 gene) can each confer very small risks but by gene-gene interactions can confer a ninefold risk for rheumatoid arthritis. These genetic risk factors have been found to confer risk for multiple autoimmune diseases. Phenotype-genotype interactions were described by the enhanced prevalence of a rheumatoid arthritis-specific autoantibody (anti-cyclic citrullinated peptide antibodies) in rheumatoid arthritis patients that harbor the rheumatoid arthritis-associated human leukocyte antigen class II genes, the shared epitope alleles. An environmental factor, smoking was demonstrated to confer risk for rheumatoid arthritis, especially in patients positive for both shared epitope and rheumatoid arthritis-specific anti-cyclic citrullinated peptide antibodies. SUMMARY Two new pathways, T cell receptor signaling and a hematopoietic-specific signal transduction pathway, have been discovered that allow future pharmacologic interventions. The description of the new genetic risk factors and the interaction with environmental triggers as well as phenotypic features are gradually expanding the ability to predict disease susceptibility and course.
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Brown MA. Genetic studies of osteoporosis--a rethink required. Calcif Tissue Int 2005; 76:319-25. [PMID: 15864466 DOI: 10.1007/s00223-004-0179-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Accepted: 12/14/2004] [Indexed: 10/25/2022]
Affiliation(s)
- M A Brown
- Botnar Research Centre, Nuffield Orthopaedic Centre, University of Oxford, Windmill Road, Headington, Oxford, OX3 7LD, United Kingdom.
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Abstract
Osteoarthritis (OA) demonstrates considerable clinical heterogeneity, generating heated debate over whether OA is a single disease or a complex mix of disparate diseases and concerning which tissues are principally involved in disease initiation and progression. Epidemiological studies have demonstrated a major genetic component to OA risk. However, these studies have also revealed differences in risk between males and females and for disease at different skeletal sites. This observation has resulted in the concept of genes for specific sites rather than a generalised OA phenotype. Recent breakthroughs have shed considerable light on the nature of OA genetic susceptibility. Many candidate genes have been confirmed, such as the interleukin-1 gene cluster and the oestrogen alpha-receptor gene ESR1. Genome-wide linkage scans have revealed several regions harbouring novel loci, some of which are beginning to yield their genes.
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Affiliation(s)
- Chris A Peach
- Nuffield Department of Orthopaedic Surgery, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7LD, UK
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Shen H, Liu Y, Liu P, Recker RR, Deng HW. Nonreplication in genetic studies of complex diseases--lessons learned from studies of osteoporosis and tentative remedies. J Bone Miner Res 2005; 20:365-76. [PMID: 15746981 DOI: 10.1359/jbmr.041129] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2004] [Revised: 08/29/2004] [Accepted: 10/15/2004] [Indexed: 12/17/2022]
Abstract
Inconsistent results have accumulated in genetic studies of complex diseases/traits over the past decade. Using osteoporosis as an example, we address major potential factors for the nonreplication results and propose some potential remedies. Over the past decade, numerous linkage and association studies have been performed to search for genes predisposing to complex human diseases. However, relatively little success has been achieved, and inconsistent results have accumulated. We argue that those nonreplication results are not unexpected, given the complicated nature of complex diseases and a number of confounding factors. In this article, based on our experience in genetic studies of osteoporosis, we discuss major potential factors for the inconsistent results and propose some potential remedies. We believe that one of the main reasons for this lack of reproducibility is overinterpretation of nominally significant results from studies with insufficient statistical power. We indicate that the power of a study is not only influenced by the sample size, but also by genetic heterogeneity, the extent and degree of linkage disequilibrium (LD) between the markers tested and the causal variants, and the allele frequency differences between them. We also discuss the effects of other confounding factors, including population stratification, phenotype difference, genotype and phenotype quality control, multiple testing, and genuine biological differences. In addition, we note that with low statistical power, even a "replicated" finding is still likely to be a false positive. We believe that with rigorous control of study design and interpretation of different outcomes, inconsistency will be largely reduced, and the chances of successfully revealing genetic components of complex diseases will be greatly improved.
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Affiliation(s)
- Hui Shen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
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Affiliation(s)
- John P A Ioannidis
- Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina 45110, Greece.
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Chen JY, Wang CM, Ma CC, Chow YH, Luo SF. The −844C/T polymorphism in the Fas ligand promoter associates with Taiwanese SLE. Genes Immun 2005; 6:123-8. [PMID: 15674374 DOI: 10.1038/sj.gene.6364158] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
FasL expression is critical in T-cell activation-induced apoptosis, which is involved in lupus pathogenesis. This study identified two SNPs in the FasL promoter regions from -1145 to -45 by genomic DNA sequencing. The -844C/T polymorphism was previously described by its location in and affect on the CCAAT/enhancer-binding protein beta (C/EBPB beta)-binding site and the other (-1094A/C, a novel polymorphism) was located at the NF-kappaB transcription-binding site. FasL gene promoter polymorphisms were genotyped in 260 systemic lupus erythematosus (SLE) patients and 280 healthy controls using MassArray matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. The distribution of FasL promoter -844C/C genotype, predominant in Taiwanese, was skewed in Taiwanese SLE patients (odds ratio: 1.53; P-value=0.014). FasL promoter -844C/T polymorphism genotype distributions of Taiwanese, African Americans, and Caucasians differed. Moreover, no particular clinical association of -844C/T and -1094A/C polymorphisms with SLE was found in patients in Taiwan. This study confirmed that -844C/C genotype is associated with lupus susceptibility. The -1094A/C polymorphism is not significantly associated with lupus disease susceptibility, albeit the role of NF-kappaB pathway in FasL promoter activation remains unclear. Fas/FasL pathway may contribute to SLE polygenic disease entity.
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Affiliation(s)
- J-Y Chen
- Division of Allergy, Immunology and Rheumatology, Department of Medicine, Chang Gung Memorial Hospital, Taiwan, Republic of China.
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Rahman P. Detailing ethnicity and phenotypes is critical for pooling association studies: Comment on the article by Huizinga et al. ACTA ACUST UNITED AC 2005; 52:676; author reply 676. [PMID: 15692998 DOI: 10.1002/art.20814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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