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Chew DCH, Khoo XH, Lee TS, Chin KY, Raja Ali RA, Muhammad Nawawi KN, Wan Ibrahim NR, Hilmi I. A Systematic Review on the Increasing Incidence of Inflammatory Bowel Disease in Southeast Asia: Looking Beyond the Urbanization Phenomenon. Inflamm Bowel Dis 2023:izad189. [PMID: 37935628 DOI: 10.1093/ibd/izad189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Indexed: 11/09/2023]
Abstract
The incidence of inflammatory bowel disease (IBD) has been increasing in Southeast Asia (SEA) in tandem with its economic growth and urbanization over the past 2 decades. Specific characteristics of IBD in SEA are similar to East Asia and the West, such as the declining ratio of ulcerative colitis to Crohn's disease. However, exceptionally low familial aggregation is seen. Smoking is also not a common risk factor in patients with Crohn's disease. The incidence of perianal disease is higher in SEA than in Australia and is comparable to the West. In a multiracial population, such as Singapore and Malaysia, Indians have the highest incidence and prevalence rates, which are likely to be due to important putative mutations. For instance, a higher frequency of the NOD2 predisposing mutation SNP5 and IBD risk allele IGR2198a and IGR2092a were found in Indians. Although differences in the genetic constitution play an important role in the epidemiology and prognosis of IBD in SEA, the emergence of this disease offers a unique opportunity to identify potential exposomes that contribute to its pathogenesis.
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Affiliation(s)
- Deborah Chia Hsin Chew
- Gastroenterology and hepatology Unit, Department of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
- GUT Research Group, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Xin-Hui Khoo
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Tiong See Lee
- Department of Gastroenterology and Hepatology, Selayang Hospital, Kuala Lumpur, Malaysia
| | - Kok-Yong Chin
- Department of Pharmacology, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
| | - Raja Affendi Raja Ali
- Gastroenterology and hepatology Unit, Department of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
- GUT Research Group, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Khairul Najmi Muhammad Nawawi
- Gastroenterology and hepatology Unit, Department of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
- GUT Research Group, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | | | - Ida Hilmi
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Li Y, Chen P, Sun J, Huang J, Tie H, Li L, Li H, Ren G. Meta-analysis of associations between DLG5 R30Q and P1371Q polymorphisms and susceptibility to inflammatory bowel disease. Sci Rep 2016; 6:33550. [PMID: 27633114 PMCID: PMC5025715 DOI: 10.1038/srep33550] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 08/30/2016] [Indexed: 01/01/2023] Open
Abstract
Growing evidence from recent studies has demonstrated an association between inflammatory bowel disease (IBD) susceptibility and two polymorphisms of DLG5 R30Q (rs1248696) and P1371Q (rs2289310), but the results remain controversial. We conducted a meta-analysis including a total of 22 studies with 10,878 IBD patients and 7917 healthy controls for R30Q and 5277 IBD cases and 4367 controls for P1371Q in order to systematically assess their association with the disease. The results indicated that R30Q was significantly associated with reduced susceptibility to IBD in Europeans by allelic and dominant comparisons, but not in overall population. No significant association was found between R30Q and Crohn's disease (CD) or ulcerative colitis (UC). P1371Q was associated with increased risk of IBD in Europeans and Americans. On the contrary, a decreased risk of IBD was observed in Asian population for P1371Q. In disease subgroup analysis, we found that P1371Q was also significantly associated with CD, but this relationship was not present for UC. In conclusion, our results strongly suggest that the both polymorphisms of DLG5 are correlated with IBD susceptibility in an ethnic-specific manner. Additional well-designed studies with large and diverse cohorts are needed to further strengthen our findings.
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Affiliation(s)
- Yunhai Li
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Ping Chen
- Department of Rheumatology, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Jiazheng Sun
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jing Huang
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Hongtao Tie
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Liangliang Li
- Department of Rheumatology, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Hongzhong Li
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Guosheng Ren
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Potentially functional SNPs (pfSNPs) as novel genomic predictors of 5-FU response in metastatic colorectal cancer patients. PLoS One 2014; 9:e111694. [PMID: 25372392 PMCID: PMC4221105 DOI: 10.1371/journal.pone.0111694] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 09/29/2014] [Indexed: 12/31/2022] Open
Abstract
5-Fluorouracil (5-FU) and its pro-drug Capecitabine have been widely used in treating colorectal cancer. However, not all patients will respond to the drug, hence there is a need to develop reliable early predictive biomarkers for 5-FU response. Here, we report a novel potentially functional Single Nucleotide Polymorphism (pfSNP) approach to identify SNPs that may serve as predictive biomarkers of response to 5-FU in Chinese metastatic colorectal cancer (CRC) patients. 1547 pfSNPs and one variable number tandem repeat (VNTR) in 139 genes in 5-FU drug (both PK and PD pathway) and colorectal cancer disease pathways were examined in 2 groups of CRC patients. Shrinkage of liver metastasis measured by RECIST criteria was used as the clinical end point. Four non-responder-specific pfSNPs were found to account for 37.5% of all non-responders (P<0.0003). Five additional pfSNPs were identified from a multivariate model (AUC under ROC = 0.875) that was applied for all other pfSNPs, excluding the non-responder-specific pfSNPs. These pfSNPs, which can differentiate the other non-responders from responders, mainly reside in tumor suppressor genes or genes implicated in colorectal cancer risk. Hence, a total of 9 novel SNPs with potential functional significance may be able to distinguish non-responders from responders to 5-FU. These pfSNPs may be useful biomarkers for predicting response to 5-FU.
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Sezaki T, Tomiyama L, Kimura Y, Ueda K, Kioka N. Dlg5 interacts with the TGF-β receptor and promotes its degradation. FEBS Lett 2013; 587:1624-9. [PMID: 23624079 DOI: 10.1016/j.febslet.2013.04.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 03/30/2013] [Accepted: 04/09/2013] [Indexed: 01/12/2023]
Abstract
Discs large homolog 5 (Dlg5) is a member of the membrane-associated guanylate kinase adaptor family of proteins and is involved in epithelial-to-mesenchymal transition via transforming growth factor-β (TGF-β) signaling. However, the mechanism underlying the regulation of TGF-β signaling is unclear. We show here that Dlg5 interacts and colocalizes with both TGF-β type I (TβRI) and type II (TβRII) receptors at the plasma membrane. TβRI activation is not required for this interaction. Furthermore, the overexpression of Dlg5 enhances the degradation of TβRI. Proteasome inhibitors inhibited this enhanced degradation. These results suggest that Dlg5 interacts with TβRs and promotes their degradation.
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Affiliation(s)
- Takuhito Sezaki
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto 606-8502, Japan
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Wagner J, Sim WH, Ellis JA, Ong EK, Catto-Smith AG, Cameron DJS, Bishop RF, Kirkwood CD. Interaction of Crohn's disease susceptibility genes in an Australian paediatric cohort. PLoS One 2010; 5:e15376. [PMID: 21079743 PMCID: PMC2975706 DOI: 10.1371/journal.pone.0015376] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 08/24/2010] [Indexed: 11/30/2022] Open
Abstract
Genetic susceptibility is an important contributor to the pathogenesis of Crohn's disease (CD). We investigated multiple CD susceptibility genes in an Australian paediatric onset CD cohort. Newly diagnosed paediatric onset CD patients (n = 72) and controls (n = 98) were genotyped for 34 single nucleotide polymorphisms (SNPs) in 18 genetic loci. Gene-gene interaction analysis, gene-disease phenotype analysis and genetic risk profiling were performed for all SNPs and all genes. Of the 34 SNPs analysed, four polymorphisms on three genes (NOD2, IL23R, and region 3p21) were significantly associated with CD status (p<0.05). All three CD specific paediatric polymorphisms on PSMG1 and TNFRSF6B showed a trend of association with p<0.1. An additive gene-gene interaction involving TLR4, PSMG1, TNFRSF6B and IRGM was identified with CD. Genes involved in microbial processing (TLR4, PSMG1, NOD2) were significantly associated either at the individual level or in gene-gene interactive roles. Colonic disease was significantly associated with disease SNP rs7517847 (IL23R) (p<0.05) and colonic and ileal/colonic disease was significantly associated with disease SNP rs125221868 (IBD5) and SLC22A4 & SLC22A4/5 variants (p<0.05). We were able to demonstrate genetic association of several genes to CD in a paediatric onset cohort. Several of the observed associations have not been reported previously in association with paediatric CD patients. Our findings demonstrate that CD genetic susceptibility in paediatric patients presents as a complex interaction between numerous genes.
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Affiliation(s)
- Josef Wagner
- Enteric Virus Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.
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Abstract
The mechanism of inflammatory bowel disease (IBD) is partially understood, but it is certain that a genetic predisposition, through the inheritance of a number of contributory genetic polymorphisms, contributes to the pathogenesis of IBD. These variant forms of genes may be associated with an abnormal response to normal luminal bacteria. Those genes that have been consistently associated with IBD thus far primarily fall into one of three classes: those affecting bacterial recognition, those affecting immune response, and a third group affecting mucosal transport polarity or mucosal transporter function. This article reviews the IBD related genes mentioned above.
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Economou M, Pappas G. New global map of Crohn's disease: Genetic, environmental, and socioeconomic correlations. Inflamm Bowel Dis 2008; 14:709-20. [PMID: 18095316 DOI: 10.1002/ibd.20352] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Seventy-five years after the initial characterization of Crohn's disease (CD), much remains obscure about its etiology. The authors sought to evaluate the incidence trends of the last 25 years worldwide, and the existence of potential correlations with genetic, environmental, and socioeconomic factors that could be etiologically implicated in the pathogenesis of CD. Relevant medical literature for individual countries on the incidence of CD, on the incidence of associated genetic mutations, and on the incidence of suggested etiologic infectious agents such as Mycobacterium avium paratuberculosis were retrieved from published medical literature, reports from relevant international congresses, and through official reports from national health authorities. Increasing trends have been observed almost worldwide, with a broad north-south gradient still prevailing in Europe. Distinct regions of New Zealand, Canada, Scotland, France, the Netherlands, and Scandinavia represent the highest incidence areas. Industrialized status and affluence are the common denominators between endemic areas, but are too broad as terms to strongly indicate any particular etiological role. The increasing trends observed in Asia still account for a low prevalence of the disease and may represent increased detection and diagnostic ability of local health systems. Genetic associations are variably reproduced worldwide, in a manner inconsistent with a strong etiologic relationship. Data on paratuberculosis incidence are scarce, and the existing ones are ambivalent regarding an even indirect correlation between CD and an infectious trigger.
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Abstract
Genome-wide association studies have firmly established that many genomic loci contribute to inflammatory bowel disease, especially in Crohn’s disease. These studies have newly-established the importance of the interleukin 23 and autophagy pathways in disease pathogenesis. Future challenges include: (1) the establishment of precisely causal alleles, (2) definition of altered functional outcomes of associated and causal alleles and (3) integration of genetic findings with environmental factors.
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Abstract
Great progress in the understanding of the molecular genetics of inflammatory bowel disease (IBD) has been made over the last 10 years. Strong epidemiological evidence, based initially on concordance data in twin/family studies, led to the application of genome-wide linkage analysis involving multiply affected families and the identification of a number of susceptibility loci. Further characterization of the IBD1 locus on chromosome 16 led to the discovery of the NOD2/CARD15 gene as the first susceptibility gene in Crohn's disease for 2001. This landmark finding has led to a redirection of basic research in IBD with interest focused principally on regulation of the innate immune response and mucosal barrier function. Within the last year, the use of genome-wide association studies has provided new insights into primary pathogenetic mechanisms; several new genes such as the Interleukin-23 receptor (IL23R) and ATG16L1 (autophagy-related 16-like 1) genes are strongly implicated. Overall, these studies promise to change our fundamental understanding of IBD pathophysiology and to have implications for clinical practice.
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Affiliation(s)
- Johan Van Limbergen
- Gastrointestinal Unit, Molecular Medicine Centre, Western General Hospital, University of Edinburgh, Edinburgh, United Kingdom
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Browning BL, Huebner C, Petermann I, Demmers P, McCulloch A, Gearry RB, Barclay ML, Shelling AN, Ferguson LR. Association of DLG5 variants with inflammatory bowel disease in the New Zealand Caucasian population and meta-analysis of the DLG5 R30Q variant. Inflamm Bowel Dis 2007; 13:1069-76. [PMID: 17455201 DOI: 10.1002/ibd.20157] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Variants in the DLG5 gene have been associated with inflammatory bowel disease (IBD) in samples from some, but not all populations. In particular, 2 nonsynonymous single-nucleotide polymorphisms (SNPs), R30Q (rs1248696) and P1371Q (rs2289310), have been associated with an increased risk of IBD, and a common haplotype (called haplotype "A") has been associated with reduced risk. METHODS We genotyped R30Q, P1371Q, and a haplotype A tagging SNP (rs2289311) in a New Zealand Caucasian cohort of 389 Crohn's disease (CD) patients, 406 ulcerative colitis (UC) patients, and 416 population controls. Each SNP was tested for association with disease susceptibility and clinical phenotypes. We also performed a meta-analysis of R30Q data from published association studies. RESULTS The haplotype A tagging SNP was associated with reduced risk of IBD at the 0.05 significance level (P=0.036) with an allelic odds ratio of 0.83 (95% confidence interval [CI]: 0.69-0.99). Association with haplotype A was strongest (odds ratio approximately 0.57) in UC patients with familial IBD or extraintestinal manifestations. The R30Q and P1371Q polymorphisms were not significantly associated with UC, CD, or IBD. Analysis of male and female data did not find any gender-specific associations. Meta-analysis gave no evidence of association of R30Q with IBD. CONCLUSIONS Meta-analysis demonstrates that the minor allele of R30Q is not a risk factor for IBD across populations. This study provides some evidence that DLG5 haplotype A is associated with reduced risk of IBD in the New Zealand Caucasian population, but this association will need to be replicated in an independent sample.
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Affiliation(s)
- Brian L Browning
- Discipline of Nutrition, Department of Statistics, University of Auckland, New Zealand, and Department of Gastroenterology, Box Hill Hospital, Monash, Australia.
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Franke A, Hampe J, Rosenstiel P, Becker C, Wagner F, Häsler R, Little RD, Huse K, Ruether A, Balschun T, Wittig M, ElSharawy A, Mayr G, Albrecht M, Prescott NJ, Onnie CM, Fournier H, Keith T, Radelof U, Platzer M, Mathew CG, Stoll M, Krawczak M, Nürnberg P, Schreiber S. Systematic association mapping identifies NELL1 as a novel IBD disease gene. PLoS One 2007; 2:e691. [PMID: 17684544 PMCID: PMC1933598 DOI: 10.1371/journal.pone.0000691] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Accepted: 06/20/2007] [Indexed: 12/14/2022] Open
Abstract
Crohn disease (CD), a sub-entity of inflammatory bowel disease (IBD), is a complex polygenic disorder. Although recent studies have successfully identified CD-associated genetic variants, these susceptibility loci explain only a fraction of the heritability of the disease. Here, we report on a multi-stage genome-wide scan of 393 German CD cases and 399 controls. Among the 116,161 single-nucleotide polymorphisms tested, an association with the known CD susceptibility gene NOD2, the 5q31 haplotype, and the recently reported CD locus at 5p13.1 was confirmed. In addition, SNP rs1793004 in the gene encoding nel-like 1 precursor (NELL1, chromosome 11p15.1) showed a consistent disease-association in independent German population- and family-based samples (942 cases, 1082 controls, 375 trios). Subsequent fine mapping and replication in an independent sample of 454 French/Canadian CD trios supported the authenticity of the NELL1 association. Further confirmation in a large German ulcerative colitis (UC) sample indicated that NELL1 is a ubiquitous IBD susceptibility locus (combined p<10−6; OR = 1.66, 95% CI: 1.30–2.11). The novel 5p13.1 locus was also replicated in the French/Canadian sample and in an independent UK CD patient panel (453 cases, 521 controls, combined p<10−6 for SNP rs1992660). Several associations were replicated in at least one independent sample, point to an involvement of ITGB6 (upstream), GRM8 (downstream), OR5V1 (downstream), PPP3R2 (downstream), NM_152575 (upstream) and HNF4G (intron).
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Affiliation(s)
- Andre Franke
- Institute for Clinical Molecular Biology, Christian-Albrechts University Kiel, Kiel, Germany
| | - Jochen Hampe
- First Department of Medicine, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Philip Rosenstiel
- Institute for Clinical Molecular Biology, Christian-Albrechts University Kiel, Kiel, Germany
| | - Christian Becker
- Cologne Center for Genomics, University of Cologne, Köln, Germany
- RZPD German Resource Center for Genome Research, Berlin, Germany
| | - Florian Wagner
- RZPD German Resource Center for Genome Research, Berlin, Germany
| | - Robert Häsler
- Institute for Clinical Molecular Biology, Christian-Albrechts University Kiel, Kiel, Germany
| | | | - Klaus Huse
- Genome Analysis Group, Leibniz Institute for Age Research, Jena, Germany
| | - Andreas Ruether
- PopGen Biobank, Christian-Albrechts University Kiel, Kiel, Germany
| | - Tobias Balschun
- Institute for Clinical Molecular Biology, Christian-Albrechts University Kiel, Kiel, Germany
| | - Michael Wittig
- PopGen Biobank, Christian-Albrechts University Kiel, Kiel, Germany
| | - Abdou ElSharawy
- Institute for Clinical Molecular Biology, Christian-Albrechts University Kiel, Kiel, Germany
| | - Gabriele Mayr
- Max-Planck Institute for Informatics, Saarbrücken, Germany
| | - Mario Albrecht
- Max-Planck Institute for Informatics, Saarbrücken, Germany
| | - Natalie J. Prescott
- Department of Medical and Molecular Genetics, King's College London School of Medicine, London, United Kingdom
| | - Clive M. Onnie
- Department of Medical and Molecular Genetics, King's College London School of Medicine, London, United Kingdom
| | | | - Tim Keith
- Genizon BioSciences5, Québec, Canada
| | - Uwe Radelof
- RZPD German Resource Center for Genome Research, Berlin, Germany
| | - Matthias Platzer
- Genome Analysis Group, Leibniz Institute for Age Research, Jena, Germany
| | - Christopher G. Mathew
- Department of Medical and Molecular Genetics, King's College London School of Medicine, London, United Kingdom
| | - Monika Stoll
- Leibniz-Institute for Arteriosclerosis Research, University Münster, Münster, Germany
| | - Michael Krawczak
- PopGen Biobank, Christian-Albrechts University Kiel, Kiel, Germany
- Institute of Medical Statistics and Informatics, Christian-Albrechts University Kiel, Kiel, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics, University of Cologne, Köln, Germany
- Center for Molecular Medicine Cologne, University of Cologne, Köln, Germany
| | - Stefan Schreiber
- Institute for Clinical Molecular Biology, Christian-Albrechts University Kiel, Kiel, Germany
- First Department of Medicine, University Hospital Schleswig-Holstein, Kiel, Germany
- PopGen Biobank, Christian-Albrechts University Kiel, Kiel, Germany
- * To whom correspondence should be addressed. E-mail:
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Ferguson LR, Shelling AN, Browning BL, Huebner C, Petermann I. Genes, diet and inflammatory bowel disease. Mutat Res 2007; 622:70-83. [PMID: 17628615 DOI: 10.1016/j.mrfmmm.2007.05.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2006] [Revised: 04/30/2007] [Accepted: 05/23/2007] [Indexed: 02/06/2023]
Abstract
Inflammatory bowel disease (IBD) arises in part from a genetic predisposition, through the inheritance of a number of contributory genetic polymorphisms. These variant forms of genes may be associated with an abnormal response to normal luminal bacteria. A consistent observation across most populations is that any of three polymorphisms of the Caspase-activated recruitment domain (CARD15) gene are more prevalent in IBD patients as compared with unaffected controls. Similar aberrant responses to bacteria are associated with variants in Autophagy-related 16-like 1 (ATG16L1) and human defensin (HBD-2, -3 and -4) genes. The defective bacterial signal in turn leads to an excessive immune response, presenting as chronic gut inflammation in susceptible individuals. Inconsistent population reports implicate the major histocompatability complex (MHC), that encodes a number of human leukocyte antigens (HLA), MHC class I chain-related gene A (MICA) or cytokines, such as tumour necrosis factor-alpha (TNF-alpha). Toll-like receptors encoded by the TLR4 or TLR9 genes may also play a role. Recent whole genome scans suggest that a rare variant in the interleukin-23 receptor (IL23R) gene may actually protect against IBD. Other implicated genes may affect mucosal cell polarity (Drosophila discs large homologue 5, DLG5) or mucosal transporter function (sodium dependent organic cation transporters, SLC22A4 and SLC22A5). A variant in ABCB1 (ATP-binding cassette subfamily B member 1) may be especially associated with increased risk of UC. While pharmacogenetics is increasingly being used to predict and optimise clinical response to therapy, nutrigenetics may have even greater potential. In many cases, IBD can be controlled through prescribing an elemental diet, which appears to act through modulating cytokine response and changing the gut microbiota. More generally, no single group of dietary items is beneficial or detrimental to all patients, and elimination diets have been used to individualise dietary requirements. However, recognising the nature of the genes involved may suggest a more strategic approach. Pro- or prebiotics will directly influence the microbial flora, while immunonutrition, including omega-3 fatty acids and certain polyphenols, may reduce the symptoms of gut inflammation. The expression of gut transporters may be modulated through various herbal remedies including green tea polyphenols. Such approaches would require that the gene of interest is functioning normally, other than its expression being up or down-regulated. However, new approaches are being developed to overcome the effects of polymorphisms that affect the function of a gene. A combination of human correlation studies with experimental models could provide a rational strategy for optimising nutrigenetic approaches to IBD.
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Affiliation(s)
- Lynnette R Ferguson
- Discipline of Nutrition, Faculty of Medical & Health Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Van Limbergen J, Russell RK, Nimmo ER, Ho GT, Arnott ID, Wilson DC, Satsangi J. Genetics of the innate immune response in inflammatory bowel disease. Inflamm Bowel Dis 2007; 13:338-55. [PMID: 17206667 DOI: 10.1002/ibd.20096] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The discovery of nucleotide-binding oligomerization domain 2/caspase recruitment domain-containing protein 15 (NOD2/CARD15) as the first susceptibility gene in Crohn's disease (CD) has shifted the focus of research into the pathogenesis of inflammatory bowel disease (IBD) firmly to the innate immune response and the integrity of the epithelial barrier. The subsequent implication in IBD of variant alleles of OCTN, DLG5, MDR1, and TLRs has provided further support for a new, more complex model of innate immunity function in the gastrointestinal tract. In this review, we examine the recent advances in our understanding of the influence of genetics of the innate immune response on IBD. We will focus on germline variation of genes encoding pathogen-recognition receptors, proteins involved in epithelial homeostasis and secreted antimicrobial proteins.
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Affiliation(s)
- Johan Van Limbergen
- Gastrointestinal Unit, Molecular Medicine Centre, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK.
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14
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Biank V, Friedrichs F, Babusukumar U, Wang T, Stoll M, Broeckel U, Kugathasan S. DLG5 R30Q variant is a female-specific protective factor in pediatric onset Crohn's disease. Am J Gastroenterol 2007; 102:391-8. [PMID: 17156146 DOI: 10.1111/j.1572-0241.2006.01011.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE A significant association between the DLG5 variant (R30Q) and inflammatory bowel disease (IBD) has been confirmed in several independent adult IBD cohorts. There is growing evidence that gender significantly influences R30Q susceptibility in Crohn's disease (CD). Pediatric onset CD features a significantly lower incidence for female children compared with male children. We, therefore, studied the influence of gender on R30Q susceptibility in an exclusively pediatric onset IBD cohort. DESIGN A total of 281 CD (181 trios) and 479 population-based controls were genotyped for DLG5 R30Q using Taqman assay. Association was tested by case-control and transmission disequilibrium testing analysis. Multivariate logistic regression was performed to investigate gene-gene and gene-gender interactions, as well as genotype-phenotype correlations. RESULTS Overall allele frequency for R30Q was 8.5% in CD and 10.3% in controls. Logistic regression showed R30Q had no association with CD (OR 0.81, 95% CI 0.55-1.20, P= 0.3) when the cohort was analyzed as a whole. Stratified by gender, a significant negative association was detected for R30Q in female children (OR 0.39, 95% CI 0.2-0.77, P= 0.006), but not in male children. Gender was found to be an effect modifier of the association between R30Q and CD as the odds ratios in female children and male children differed significantly. The gender-specific association of R30Q and CD was independent of additional CD risk factors such as CARD15 and IBD5. CONCLUSIONS DLG5 has a gender-specific role in the susceptibility of pediatric CD. Specifically, the significant negative association found between DLG5 R30Q and CD in female children suggests DLG5 may have a protective effect in CD susceptibility for female children.
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Affiliation(s)
- Vincent Biank
- Department of Pediatrics, Medical College Wisconsin, Milwaukee, Wisconsin 53226, USA
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Goyette P, Labbé C, Trinh TT, Xavier RJ, Rioux JD. Molecular pathogenesis of inflammatory bowel disease: genotypes, phenotypes and personalized medicine. Ann Med 2007; 39:177-99. [PMID: 17457716 DOI: 10.1080/07853890701197615] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Crohn's disease (CD) and ulcerative colitis (UC), also known as inflammatory bowel diseases (IBD), are characterized by chronic inflammation of the gastrointestinal tract. IBD is among the few complex diseases for which several genomic regions and specific genes have been identified and confirmed in multiple replication studies. We will review the different loci implicated in disease risk in the context of three proposed mechanisms leading to chronic inflammation of the gut mucosa: 1) deregulation of the innate immune response to enteric microflora or pathogens; 2) increased permeability across the epithelial barrier; and 3) defective regulation of the adaptive immune system. As our knowledge of genetic variation, analytical approaches and technology improves, additional genetic risk factors are expected to be identified. With the identification of novel risk variants, additional pathophysiological mechanisms are likely to emerge. The resulting discoveries will further our molecular understanding of IBD, potentially leading to improved disease classification and rational drug design. Moreover, these approaches and tools can be applied in the context of variable drug response with the goal of providing more personalized clinical management of patients with IBD.
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Affiliation(s)
- Philippe Goyette
- Université de Montréal, Department of Medicine, Montréal, Québec, Canada
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16
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Abstract
In 2004, an association of genetic variation in the discs large homolog 5 (DLG5) gene with inflammatory bowel disease (IBD) was described in two large European study samples. The initial report of DLG5 as a novel IBD susceptibility gene sparked a multitude of studies investigating its effect on CD and IBD, respectively, leading to controversial findings and ongoing discussions concerning the validity of the initial association finding and its role in the aetiology of Crohn disease. This review aims to summarize the current state of knowledge and to place the reported findings in the context of current concepts of complex diseases. This includes aspects of statistical power, phenotype differences and genetic heterogeneity between different populations as well as gene-gene and gene-environment interactions.
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Affiliation(s)
- Frauke Friedrichs
- Genetic Epidemiology of vascular disorders, Leibniz-Institute for Arteriosclerosis Research at the University of Muenster, Germany
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17
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Abstract
The translation of basic science advances to tangible benefits in clinical practice remains a fundamental goal of biomedical research. Genetic approaches provide a unique opportunity to enhance bench-to-bedside translational efforts, with inflammatory bowel disease (IBD) being a model genetic disorder in several respects. The association of the NOD2 (CARD15) mutations to Crohn's disease (CD) represents, in complex human disorders, one of the clearest cases of a definitive disease association. The NOD2 gene is located in the IBD1 genetic linkage region on chromosome 16 and functions as an intracellular pattern recognition receptor for components of bacterial peptidoglycan. CD-associated variants within NOD2 have a decreased capacity to appropriately signal with peptidoglycan and provide an important example of gene-environment interactions. Genetic variation in other innate immune receptors, notably Toll-like receptor (TLR)4, has been defined and may also play a role in CD pathogenesis. Replicated CD association in the IBD5 region on chromosome 5q has been reported, and candidate functional polymorphisms within the organic cation transporters OCTN1 (SLC22A4) and OCTN2 (SLC22A5) have been described. Confirmatory studies demonstrating altered OCTN activity and expression in primary human cells stratified on the IBD5 risk haplotype would provide important confirmatory support for disease contribution. A comprehensive understanding of IBD will involve integrating information from animal models, functional human polymorphisms, and expression studies from human IBD tissues. Genes and pathways implicated as contributing to IBD pathogenesis through multiple lines of evidence should be more intensively examined, including the tumor necrosis factor-alpha, MDR1, and peroxisome proliferator-activated receptor (PPAR)gamma pathways. To attain full advantage of new genetic information, novel methods of classifying patients that go beyond phenotypic classifications presently utilized will be required. Genetic data will need to be integrated with novel biomarker development in IBD, including functional, expression (mRNA or protein), or biochemical indicators of physiologic/disease processes and responses to therapies.
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Affiliation(s)
- Judy Cho
- University of Chicago Hospitals, 5841 South Maryland Avenue, Chicago, IL 60637, USA.
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18
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Abstract
Recent advances in the field of inflammatory bowel disease (IBD) genetics have enabled the definition and refinement of multiple IBD susceptibility loci and the identification of gene variants within such regions showing association with Crohn's disease (CD) and/or ulcerative colitis (UC). Most notable among the newly defined genetic determinants of IBD are specific variants in the CARD15 gene, which have been shown widely to influence both susceptibility and phenotype in CD. These genetic data have inspired intensive studies of CARD15 biologic functions and the information emerging from these analyses has already substantively enhanced understanding of the signaling pathways coupling bacterial pathogens to the host immune response. Genetic data implicating various other signaling effectors in IBD susceptibility have similarly focused attention on the molecular pathways driven or regulated by these proteins and the biochemical events linking effector/pathway dysfunction to intestinal inflammation and disease. In this review, progress in defining the genetic determinants of IBD is described with an emphasis on the impact of such knowledge on understanding of IBD molecular pathophysiology.
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Affiliation(s)
- Katherine Anne Siminovitch
- Department of Medicine, University of Toronto, Mount Sinai Hospital Samuel Lunenfeld and Toronto General Hospital Research Institutes, 600 University Avenue, Room 778D, Toronto, Ont., Canada M5G 1X5.
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19
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Abstract
The chronic inflammatory bowel diseases Crohn's disease and ulcerative colitis are common causes of gastrointestinal disease in northern Europe, affecting as many as one in 250 people. Although mortality is low, morbidity associated with these diseases is substantial. We review the recent advances in the genetics of inflammatory bowel disease, with particular emphasis on the data that have been generated since the discovery of the CARD15 (NOD2) gene in 2001.
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Affiliation(s)
- Daniel R Gaya
- Gastrointestinal Unit, Molecular Medicine Centre, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
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