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Query: UMLS:C0022104 (irritable bowel syndrome)
 8,033 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During the past decade, a tremendous wealth of information regarding the pathogenesis, genetics, and therapy of IBD has been discovered. Judging by the number of new publications published every month in scientific journals and the great enthusiasm at scientific meetings, this outstanding pace surely will continue. In the near future, clinicians may be able to classify IBD into several subtypes depending on patients' cytokine and gene profiles. For example, two groups of researchers recently have identified mutation in the NOD2 gene, which is associated with susceptibility to CD. This identification may allow the clinician to better predict outcome and response to medical therapy. At the same time, several promising new therapies are being investigated. Technologic advances will continue to result in the development of potent and specific agents that will control and possibly correct the abnormal inflammatory processes responsible for pediatric IBD.
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PMID:Biological and novel therapies for inflammatory bowel disease in children. 1182

The complex genetics of IBD is characterized by more than one susceptibility locus, genetic heterogeneity, incomplete penetrance, and probable gene-gene and gene-environment interactions. Functional candidate gene association studies during the past few decades have revealed only modest associations between IBD and genetic variants in the HLA genes and a limited number of other genes that are involved in immune regulation and the inflammatory response. Important advances in IBD genetics research have come about from systematic genome searches for IBD loci. The identification of Crohn's disease-associated NOD2 genetic variants that appear to alter the innate immune response to bacteria is a seminal finding that perhaps is the greatest advance toward understanding the pathogenesis of IBD in decades. The future discovery of other IBD genetic risk factors, facilitated by the completion of the human genome sequencing and annotation, may allow the development of better therapies, possibly including preventive therapies, for patients with Crohn's disease and ulcerative colitis.
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PMID:The genetics of inflammatory bowel disease. 1212 44

We have previously reported strong evidence for linkage between IBD1 and Crohn's disease (CD) in Australian Crohn's disease families. Three risk alleles for Crohn's disease, (Arg702Trp (C/T), Gly908Arg (G/C) and 980fs981 (-/C), were recently identified in the CARD15/NOD2 gene on chromosome 16, implicating this as the IBD1 locus. Using a novel diagnostic PCR-RFLP, we have examined the frequency of these alleles in 205 multiplex IBD families, 107 sporadic Crohn's disease cases and 409 normal individuals. We demonstrate that the three risk alleles are more frequent in Crohn's disease, than in controls, with allelic frequencies of 0.11, 0.02 and 0.07 respectively. Heterozygosity for individual variants conferred a three-fold increase in risk for Crohn's disease while substantially higher risks were associated with being homozygous or compound heterozygous. Despite a significantly lower population allele frequency for the frameshift mutation than reported by other groups, we see a similar contribution by this allele to the risk of developing Crohn's disease. While the three risk alleles influence susceptibility to Crohn's disease in Australia, we show that these alleles do not fully explain the linkage evidence and suggest that there are very likely additional IBD1 susceptibility alleles yet to be described in Australian CD at the NOD2 locus. We also show a second linkage peak in Australian CD that provides some support for a second disease susceptibility locus on chromosome 16.
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PMID:CARD15/NOD2 risk alleles in the development of Crohn's disease in the Australian population. 1255 33

Linkage of IBD to the pericentromeric region of chromosome 16 has been widely confirmed by analyses of multiple populations. The NOD2 gene is located in the peak region of linkage on chromosome 16 and thought to be involved in the activation of nuclear factor (NF) kappaB in response to bacterial components. Mutations in the NOD2 gene are found to be strongly associated with susceptibility to Crohn's disease (CD). A total of 65 Irish CD families were genotyped to determine if NOD2 mutations conferred susceptibility to CD and the prevalence of these mutations in sporadic and familial forms of the disease. The Irish population is relatively homogenous and thus may provide advantages in genetic studies of complex diseases. We confirmed the IBD1 locus as a susceptibility locus for IBD within the Irish population by linkage analysis followed by linkage disequilibrium studies. No significant evidence of linkage was observed to the previously identified regions on chromosomes 1, 12 and 14. In all, 131 CD affected families were then genotyped for seven of the previously published NOD2 single-nucleotide polymorphisms (SNPs). Allelic transmission distortion was investigated using the pedigree disequilibrium test (PDT). SNP13 (3020insC) was found to be associated with CD (P=0.0186). Patients who possessed a rare allele of SNP8, 12 or 13 presented earlier when compared to patients without rare variants (mean age, 20.1 vs 24 years, P=0.011) and the rare allele of SNP13 was observed to be predominantly linked to ileal disease (P=0.02). This report confirms the importance of NOD2 as a susceptibility gene for CD within the Irish population.
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PMID:Association of NOD2 with Crohn's disease in a homogenous Irish population. 1267 78

The Inflammatory Bowel Disease International Genetic Consortium was formed in Oxford in 1997. Since then it has grown to include twelve groups from around the world that are each actively involved in identifying the genes that are involved in susceptibility to IBD. The approach of the IBDIGC is to attempt to overcome one of the major issues in complex disease analysis-that of obtaining sufficient power to analyze successfully the inheritance of IBD-by collaboratively studying large numbers of well documented families with multiple affected individuals. This strategy has been marked by considerable success with the publication of a paper authored by the IBDIGC substantiating the localization of IBD1 to chromosome 16. This publication served to encourage researchers and eventually resulted in the identification by several groups simultaneously of risk alleles in the NOD2 gene that cosegregate with disease. The IBDIGC provides a model for studies in complex disease genetics, showing that research groups both large and small can participate equally in complex disease gene identification through the formation of large international consortia.
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PMID:IBD International Genetics Consortium: international cooperation making sense of complex disease. 1279 25

Previously we have conducted a genome-wide search for inflammatory bowel disease susceptibility loci in a large European cohort. Results from this study demonstrated suggestive evidence of linkage to loci at chromosomes 1q, 6p, and 10p and replicated linkages on chromosomes 12 and 16. Recently, NOD2/CARD15 on chromosome 16q12 has been found to be strongly associated with Crohn's disease. In order to determine if there are other loci in the genome that interact with the three associated functional variants in CARD15 (R702W, G908R, 1007fs), we have stratified our large inflammatory bowel disease genome scan cohort by dividing pedigrees into two groups stratified by CARD15 variant genotype. The two pedigree groups were analysed using non-parametric allele sharing methods. The group of pedigrees that contained one of the three CARD15 variants had two suggestive linkage results occurring in 6p (lod = 3.06 at D6S197, IBD phenotype) and 10p (lod=2.29 at D10S197, CD phenotype). In addition, at 16q12 where CARD15 is located, the original genome scan had a peak lod score of 2.18 at D16S415 (CD phenotype). The stratified pedigree cohort containing one of three CARD15 variants had a peak lod score of 0.90 at D16S415 (CD phenotype), accounting for approximately less than half of the genetic evidence for linkage at this locus. This result is in agreement with the existence of a substantial number of private variants at the NOD2/CARD15 locus. Interaction with NOD2/CARD15 needs to be considered in future gene identification efforts on chromosomes 6 and 10.
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PMID:Stratification by CARD15 variant genotype in a genome-wide search for inflammatory bowel disease susceptibility loci. 1368 Mar 63

In the rich, developed parts of the world there has been a steady and simultaneous increase in at least three groups of disease: (1) allergies, (2) inflammatory bowel diseases (IBD; e.g. Crohn's disease and ulcerative colitis) and (3) autoimmunity (e.g. type 1 diabetes and multiple sclerosis). Because the medical world is so compartmentalised it was some time before the connection between these increases was noticed and understood. There is now evidence that the simultaneous increase in these diseases of immunodysregulation is at least partly attributable to malfunction of regulatory T cells (Treg). This paper provides an overview of relevant work in each of these fields of medicine (though with emphasis on the allergic disorders), and concludes that the increasing failure of Treg is a consequence of diminished exposure to certain micro-organisms that are "old friends", because of their continuous presence throughout mammalian evolution. These organisms, which include saprophytic mycobacteria, helminths and lactobacilli, are recognised by the innate immune system as harmless, and as adjuvants for Treg induction. Polymorphisms of components of the innate immune system such as TLR2 and NOD2 appear to define subsets of the population that will develop immunoregulatory disorders when living in the modern environment. A further role of the "old friends" and of the Treg that they induce might be to maintain the levels of regulatory IL-10 secreting macrophages and antigen-presenting cells, which are depleted in asthma and Crohn's disease. These concepts are leading to novel therapies based on harmless organisms or their components. Phase I/II clinical trials have yielded some statistically significant results, and phase II trials are in progress.
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PMID:Mycobacteria and other environmental organisms as immunomodulators for immunoregulatory disorders. 1500 29

Anti-Saccharomyces cerevisiae antibodies (ASCAs) have been proposed as serological markers, which may differentiate Crohn's disease (CD) from ulcerative colitis (UC) and predict disease phenotype. Their importance in pathogenesis is unproven. We investigated the relationship between ASCAs, disease phenotype and NOD2/CARD15 genotype in CD and whether ASCAs were related to antibodies to other fungal proteins. Serum from 228 patients [143 CD, 75 UC, 10 with indeterminate colitis (IC)] and 78 healthy controls (HC) were assayed for ASCA. Antibodies (IgA, IgG) to other fungal proteins (Fusarium species ATC20334, Mycoprotein) were measured in the same samples using an in-house enzyme-linked immunosorbent assay (ELISA) assay. ASCAs were present in 57% of CD, 19% of UC, 30% of IC and 8% of HCs. ASCA-positive status was a predictor for CD with sensitivity of 57%, specificity of 87%, positive predictive value of 78% and negative predictive value of 68%. ASCA was associated with proximal (gastroduodenal and small bowel involvement) rather than purely colonic disease (P < 0.001) and with a more severe disease phenotype and requirement for surgery over a median follow-up time of 9 years (P < 0.0001). No associations with NOD2/CARD15 mutations were seen. There was no association between ASCA and antibodies to MP (IgA or IgG). These data implicate ASCA as a specific marker of disease location and progression in CD, emphasizing the heterogeneity within IBD.
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PMID:Anti-Saccharomyces cerevisiae antibodies (ASCA) in Crohn's disease are associated with disease severity but not NOD2/CARD15 mutations. 1500 84

Sarcoidosis is a systemic inflammatory disease clinically characterized by swelling of bilateral hilar lymph nodes and histologically defined by non-caseating epithelioid cell granulomas. Among child cases, a special subtype, called the early-onset sarcoidosis, is known to appear in children younger than 4 years of age and to be characterized by a distinct triad of skin, joint and eye disorders without pulmonary involvement. On the other hand, autosomal dominantly-transmitted disease with a characteristic features similar to those of early-onset sarcoidosis has been reported as Blau syndrome. By a linkage analysis, the responsible gene for Blau syndrome has been mapped close to the IBD (Inflammatory Bowel Disease) 1 locus. After CARD15 (NOD2), originally identified as the susceptibility gene for Crohn's disease, was also proved to be responsible for Blau syndrome, the same gene mutations have been found in sporadic early-onset sarcoidosis cases. Nod2 recognizes a signal from bacterial cell wall component in the cytoplasm of monocytic cells to activate NF-kappaB, and thus can work as an intracellular sensor of bacteria. While the loss-of-function mutations in its LRR domain are associated with Crohn's disease, Blau syndrome and early-onset sarcoidosis are autoinflammatory diseases that are caused by the gain-of-function mutations in its NOD domain.
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PMID:[Clinical features of Blau syndrome and early-onset sarcoidosis and associating CARD15/NOD2 gene mutations]. 1747 15

Inflammatory bowel disease is a complex multifactorial disease with a strong genetic component. Recent studies have identified innate immunity (NOD2), autophagy (ATG16L1) and Th17 pathway (IL23R) genes in the pathogenesis of Crohn's disease. The pathogenesis of ulcerative colitis (UC) is less clear; however, there is growing evidence that proteins involved in the apical junction complex are involved in UC. Here we review the up-to-date studies on the genetic basis for IBD and explore the newly described UC-associated apical junction complex pointing to a primary defect in barrier defense. We will focus on the PTPRS (encoding PTPsigma) gene and discuss its and other apical junction complex proteins' role in the pathogenesis of UC.
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PMID:Apical junction complex proteins and ulcerative colitis: a focus on the PTPRS gene. 1859 28


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