| 1. |
- 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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| 2. |
- Momozawa, Y, et al.
(författare)
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IBD risk loci are enriched in multigenic regulatory modules encompassing putative causative genes
- 2018
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1, s. 2427-
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Tidskriftsartikel (refereegranskat)abstract
- GWAS have identified >200 risk loci for Inflammatory Bowel Disease (IBD). The majority of disease associations are known to be driven by regulatory variants. To identify the putative causative genes that are perturbed by these variants, we generate a large transcriptome data set (nine disease-relevant cell types) and identify 23,650 cis-eQTL. We show that these are determined by ∼9720 regulatory modules, of which ∼3000 operate in multiple tissues and ∼970 on multiple genes. We identify regulatory modules that drive the disease association for 63 of the 200 risk loci, and show that these are enriched in multigenic modules. Based on these analyses, we resequence 45 of the corresponding 100 candidate genes in 6600 Crohn disease (CD) cases and 5500 controls, and show with burden tests that they include likely causative genes. Our analyses indicate that ≥10-fold larger sample sizes will be required to demonstrate the causality of individual genes using this approach.
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| 6. |
- 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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| 7. |
- Trepo, E., et al.
(författare)
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Association Between the PNPLA3 (rs738409 C > G) Variant and Hepatocellular Carcinoma: Evidence From a Meta-Analysis of Individual Participant Data
- 2014
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Ingår i: Hepatology. - : Ovid Technologies (Wolters Kluwer Health). - 0270-9139. ; 59:6, s. 2170-2177
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Tidskriftsartikel (refereegranskat)abstract
- The incidence of hepatocellular carcinoma (HCC) is increasing in Western countries. Although several clinical factors have been identified, many individuals never develop HCC, suggesting a genetic susceptibility. However, to date, only a few single-nucleotide polymorphisms have been reproducibly shown to be linked to HCC onset. A variant (rs738409 C>G, encoding for p.I148M) in the PNPLA3 gene is associated with liver damage in chronic liver diseases. Interestingly, several studies have reported that the minor rs738409[G] allele is more represented in HCC cases in chronic hepatitis C (CHC) and alcoholic liver disease (ALD). However, a significant association with HCC related to CHC has not been consistently observed, and the strength of the association between rs738409 and HCC remains unclear. We performed a meta-analysis of individual participant data including 2,503 European patients with cirrhosis to assess the association between rs738409 and HCC, particularly in ALD and CHC. We found that rs738409 was strongly associated with overall HCC (odds ratio [OR] per G allele, additive model = 1.77; 95% confidence interval [CI]: 1.42-2.19; P = 2.78 x 10(-7)). This association was more pronounced in ALD (OR = 2.20; 95% CI: 1.80-2.67; P = 4.71 x 10(-15)) than in CHC patients (OR = 1.55; 95% CI: 1.03-2.34; P = 3.52 x 10(-2)). After adjustment for age, sex, and body mass index, the variant remained strongly associated with HCC. Conclusion: Overall, these results suggest that rs738409 exerts a marked influence on hepatocarcinogenesis in patients with cirrhosis of European descent and provide a strong argument for performing further mechanistic studies to better understand the role of PNPLA3 in HCC development.
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| 8. |
- 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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| 9. |
- Peyrin-Biroulet, L, et al.
(författare)
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Results from the 2nd Scientific Workshop of the ECCO (I): Impact of mucosal healing on the course of inflammatory bowel disease
- 2011
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Ingår i: Journal of Crohn's and Colitis. - 1873-9946. ; 5:5, s. 477-483
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Tidskriftsartikel (refereegranskat)abstract
- Over the past years, mucosal healing has emerged as a major therapeutic goal in clinical trials in inflammatory bowel diseases. Accumulating evidence indicates that mucosal healing may change the natural course of the disease by decreasing the need for surgery and reducing hospitalization rates in both ulcerative colitis and Crohn's disease. Mucosal healing may also prevent the development of long-term disease complications, such as bowel damage in Crohn's disease and colorectal cancer in ulcerative colitis. Histologic healing may be the ultimate therapeutic goal in ulcerative colitis, whereas its impact on the course of Crohn's disease is unknown. Complete mucosal healing may be required before considering drug withdrawal. Targeting early Crohn's disease is more effective than approaches aimed at healing mucosa in longstanding disease. Several questions remain to be answered: should mucosal healing be systematically used in clinical practice? Should we optimize therapies to achieve mucosal healing? What is the degree of intestinal healing that is required to change the disease course? Large prospective studies addressing these issues are needed.
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