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- Romagnoni, A, et al.
(författare)
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Comparative performances of machine learning methods for classifying Crohn Disease patients using genome-wide genotyping data
- 2019
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1, s. 10351-
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Tidskriftsartikel (refereegranskat)abstract
- Crohn Disease (CD) is a complex genetic disorder for which more than 140 genes have been identified using genome wide association studies (GWAS). However, the genetic architecture of the trait remains largely unknown. The recent development of machine learning (ML) approaches incited us to apply them to classify healthy and diseased people according to their genomic information. The Immunochip dataset containing 18,227 CD patients and 34,050 healthy controls enrolled and genotyped by the international Inflammatory Bowel Disease genetic consortium (IIBDGC) has been re-analyzed using a set of ML methods: penalized logistic regression (LR), gradient boosted trees (GBT) and artificial neural networks (NN). The main score used to compare the methods was the Area Under the ROC Curve (AUC) statistics. The impact of quality control (QC), imputing and coding methods on LR results showed that QC methods and imputation of missing genotypes may artificially increase the scores. At the opposite, neither the patient/control ratio nor marker preselection or coding strategies significantly affected the results. LR methods, including Lasso, Ridge and ElasticNet provided similar results with a maximum AUC of 0.80. GBT methods like XGBoost, LightGBM and CatBoost, together with dense NN with one or more hidden layers, provided similar AUC values, suggesting limited epistatic effects in the genetic architecture of the trait. ML methods detected near all the genetic variants previously identified by GWAS among the best predictors plus additional predictors with lower effects. The robustness and complementarity of the different methods are also studied. Compared to LR, non-linear models such as GBT or NN may provide robust complementary approaches to identify and classify genetic markers.
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| 5. |
- Franke, Andre, et al.
(författare)
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Genome-wide meta-analysis increases to 71 the number of confirmed Crohn's disease susceptibility loci
- 2010
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 42:12, s. 1118-1125
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Tidskriftsartikel (refereegranskat)abstract
- We undertook a meta-analysis of six Crohn's disease genome-wide association studies (GWAS) comprising 6,333 affected individuals (cases) and 15,056 controls and followed up the top association signals in 15,694 cases, 14,026 controls and 414 parent-offspring trios. We identified 30 new susceptibility loci meeting genome-wide significance (P < 5 × 10⁻⁸). A series of in silico analyses highlighted particular genes within these loci and, together with manual curation, implicated functionally interesting candidate genes including SMAD3, ERAP2, IL10, IL2RA, TYK2, FUT2, DNMT3A, DENND1B, BACH2 and TAGAP. Combined with previously confirmed loci, these results identify 71 distinct loci with genome-wide significant evidence for association with Crohn's disease.
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| 6. |
- Campieri, M, et al.
(författare)
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Session II and III panel discussion
- 2000
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Ingår i: DRUGS OF TODAY. - 1699-3993. ; 36, s. 93-101
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Dideberg, Vinciane, et al.
(författare)
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An insertion-deletion polymorphism in the Interferon Regulatory Factor 5 (IRF5) gene confers risk of inflammatory bowel diseases
- 2007
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 16:24, s. 3008-3016
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Tidskriftsartikel (refereegranskat)abstract
- The interferon regulatory factor 5 (IRF5) gene encodes a transcriptionfactor that plays an important role in the innate as well asin the cell-mediated immune responses. The IRF5 gene has beenshown to be associated with systemic lupus erythematosus andrheumatoid arthritis. We studied whether the IRF5 gene is alsoassociated with inflammatory bowel diseases (IBD), Crohn disease(CD) and ulcerative colitis (UC). Twelve polymorphisms in theIRF5 gene were genotyped in a cohort of 1007 IBD patients (748CD and 241 UC) and 241 controls from Wallonia, Belgium. Thesame polymorphisms were genotyped in a confirmatory cohort of311 controls and 687 IBD patients (488 CD and 192 UC) from Leuven,Belgium. A strong signal of association (p = 1.9 x 10–5,OR: 1.81 (1.37-2.39)) with IBD was observed for a 5bp indel(CGGGG) polymorphism in the promoter region of the IRF5 gene.The association was detectable (p = 6.8 x 10–4) also inCD patients, and was particularly strong among the UC patients(p = 5.3 x 10–8, OR 2.42 (1.76 -3.34)). The associationof the CGGGG indel was confirmed in the second cohort (p = 3.2x 10–5, OR 1.59 (1.28 - 1.98)). The insertion of one CGGGGunit is predicted to create an additional binding site for thetranscription factor SP1. Using an electrophoretic mobilityshift assay we show allele-specific differences in protein bindingto this repetitive DNA-stretch, which suggest a potential functionrole for the CGGGG indel.
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| 8. |
- Ellinghaus, David, et al.
(författare)
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Association between variants of PRDM1 and NDP52 and Crohn's disease, based on exome sequencing and functional studies
- 2013
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Ingår i: Gastroenterology. - : Elsevier BV. - 0016-5085 .- 1528-0012. ; 145:2, s. 339-347
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Genome-wide association studies (GWAS) have identified 140 Crohn's disease (CD) susceptibility loci. For most loci, the variants that cause disease are not known and the genes affected by these variants have not been identified. We aimed to identify variants that cause CD through detailed sequencing, genetic association, expression, and functional studies.METHODS: We sequenced whole exomes of 42 unrelated subjects with CD and 5 healthy subjects (controls) and then filtered single nucleotide variants by incorporating association results from meta-analyses of CD GWAS and in silico mutation effect prediction algorithms. We then genotyped 9348 subjects with CD, 2868 subjects with ulcerative colitis, and 14,567 control subjects and associated variants analyzed in functional studies using materials from subjects and controls and in vitro model systems.RESULTS: We identified rare missense mutations in PR domain-containing 1 (PRDM1) and associated these with CD. These mutations increased proliferation of T cells and secretion of cytokines on activation and increased expression of the adhesion molecule L-selectin. A common CD risk allele, identified in GWAS, correlated with reduced expression of PRDM1 in ileal biopsy specimens and peripheral blood mononuclear cells (combined P = 1.6 x 10(-8)). We identified an association between CD and a common missense variant, Val248Ala, in nuclear domain 10 protein 52 (NDP52) (P = 4.83 x 10(-9)). We found that this variant impairs the regulatory functions of NDP52 to inhibit nuclear factor kappa B activation of genes that regulate inflammation and affect the stability of proteins in Toll-like receptor pathways.CONCLUSIONS: We have extended the results of GWAS and provide evidence that variants in PRDM1 and NDP52 determine susceptibility to CD. PRDM1 maps adjacent to a CD interval identified in GWAS and encodes a transcription factor expressed by T and B cells. NDP52 is an adaptor protein that functions in selective autophagy of intracellular bacteria and signaling molecules, supporting the role of autophagy in the pathogenesis of CD.
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