Prevalence of mutations of the NOD2/CARD15 gene and relation to phenotype in Spanish patients with Crohn disease

NOD2 and Crohn's Disease Clinical Practice: From Epidemiology to Diagnosis and Therapy, Rewired

Crohn's disease (CD) is a chronic inflammatory bowel disease with a multifactorial pathogenesis involving environmental and genetic factors. Since the late 20th century, the discovery of the first susceptibility gene (NOD2, previously referred to as CARD15) for CD has paved the way for further investigations into the correlations between clinical features and genetics, and its potential impact on clinical practice has fueled the research in the last 2 decades. Recent therapeutic advancements involving novel biologic drugs and small molecules have shifted inflammatory bowel disease management from a disease-centered to a patient-centric approach. To date, the role of NOD2 has not been fully understood yet. Recent data suggest that its clinical impact may be greater than currently recognized. This review overviews the most common NOD2 variants' role in real-life clinical practice. These genetic variants increase the risk of developing the disease and can aid in tailoring diagnosis and treatment. They are associated with the stricturing phenotype and ileal involvement and increase the risk of steroid refractoriness. In the meantime, limited and inconclusive evidence exists regarding their predictive role in response to azathioprine, biologic drugs, and small molecules. Eventually, their role in increasing the risk for surgery is evident, especially in those with the L1007fs variant. If further trials will support the initial evidence reported so far, NOD2 genetic variants will emerge as possible candidates for developing precision medicine in CD.

Ileocolonic Healing After Extended Small Bowel Resection in Mice: NOD2 Deficiency Impairs Anastomotic Healing and Postoperative Outcome

BACKGROUND

Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) mutations are a genetic risk factor for Crohn disease. Ileocecal resection is the most often performed surgery in Crohn disease. We investigated the effect of Nod2 knockout (KO) status on anastomotic healing after extended ileocecal resection (ICR) in mice.

METHODS

Male C57BL6/J wild-type and Nod2 KO mice underwent an 11 cm resection of the terminal ileum including the cecum. An end-to-end jejuno-colostomy was performed. Animals were killed after 5 days investigating bursting pressure, hydroxyproline content, and expression of matrix metabolism genes, key cytokines, and histology of the anastomosis.

RESULTS

Mortality was higher in the Nod2 KO group but not because of local or septic complications. Bursting pressure was significantly reduced in the Nod2 KO mice (32.5 vs 78.0 mmHg, P < 0.0024), whereas hydroxyprolin content was equal. The amount of granulation tissue at the anastomosis was similar but more unstructured in the Nod2 KO mice. Gene expression measured by real-time polymerase chain reaction showed significantly increased expression for Collagen 1alpha and for collagen degradation as measured by matrix metalloproteinase-2, -9, and -13 in the Nod2 KO mice. Gelatinase activity from anastomotic tissue was enhanced by Nod2 status. Gene expression of arginase I, tumor necrosis factor-α, and transforming growth factor-ß but not inducible nitric oxide synthase were also increased at the anastomosis in the Nod2 KO mice compared with the control mice.

CONCLUSIONS

We found that Nod2 deficiency results in significantly reduced bursting pressure after ileocecal resection. This effect is mediated via an increased matrix turnover. Patients with genetic NOD2 variations may be prone to anastomotic failure after bowel resection.

[NOD2 gene mutation in Moroccan patients with Crohn's disease: prevalence, genotypic study and correlation of NOD2 gene mutation with the phenotype of Crohn's disease]

L'objectif était de déterminer la prévalence des mutations du gène NOD2/CARD15 dans un groupe de patients Marocains atteint de Maladie de Crohn et étudier sa corrélation génotype-expression phénotypique. Etude transversale cas témoin menée sur une durée de 16 mois. Ont été inclus 101 patients atteints de la maladie de Crohn, entre Janvier 2012 et Avril 2013 ainsi qu'un groupe contrôle de 107 patients. L'analyse génétique a consisté à rechercher 3 variants du gène NOD2: p.Arg702Trp, p.Gly908Arg et p.Leu1007fsins. Puis une étude de corrélation génotype-expression phénotypique a été menée. L'analyse génétique des patients atteint de maladie de crohn a mis en évidence la présence de la mutation NOD2 chez 14 patients (13,77%) contre 7 patients (6,53%) du groupe témoin. L'étude de la fréquence des différents allèles a retrouvé la mutation de p.Gly908Arg dans 6,43%, p.Leu1007fsins dans 0,99% et p.Arg702Trp dans 0,49% contre respectivement 2,80%, 0% et 0,46% dans le groupe témoin. L'étude de la corrélation génotype, expression phénotypique a démontré que la mutation CARD15 est corrélée à une localisation iléo-caecale de la maladie, à une présentation fistulisante et sténosante ainsi qu'à une évolution sévère avec recours fréquent à la chirurgie et aux immunosuppresseurs. La prévalence de la mutation NOD2/ CARD15 dans notre série est faible. Cette mutation est corrélée à une forme grave de la maladie.

Genetic and environmental factors significant for the presentation and development of inflammatory bowel disease

OBJECTIVES

The aim of the study was to evaluate associations between inflammatory bowel disease (IBD) presentation and variants in NOD2, TLR4, TNF-α, IL-6, IL-1β, and IL-RN genes in order to identify possible environmental factors that may affect IBD occurrence, investigate potential predictors for surgical treatment of IBD, and correlate the presence of granulomas in biopsy specimens with clinical characteristics of Crohn's disease (CD) patients.

PATIENTS AND METHODS

We genotyped 167 IBD patients using PCR-based methodology and tested for disease genotype-phenotype associations.

RESULTS

In CD patients ileal localization of disease was more frequent in NOD2 variant carriers. Ileal CD was associated with IL-6 GC+CC genotypes, identifying C allele as a possible marker of increased risk for ileal CD. In CD patients a positive family history for IBD was related to earlier onset of disease, higher risk for CD-related surgery, and appendectomy. CD patients who are TLR4 299Gly carriers are at higher risk for surgery at onset of the disease compared with TLR4 299Asp variant carriers. The presence of granuloma in biopsy specimens was more frequent in patients in whom a diagnosis of CD was made during emergency surgery. Multivariate analysis showed that CD carriers of the 299Gly allele had a 4.6-fold higher risk for emergency surgery before CD diagnosis is established compared with noncarriers, suggesting an aggressive disease course. Granuloma in endoscopic biopsies is detected 5.4-fold more frequently in patients treated surgically at the time of diagnosis.

CONCLUSION

Genetic variants together with epidemiological and clinical data of IBD patients could potentially be used as predictors of the disease course.

The NOD2-Smoking Interaction in Crohn's Disease is likely Specific to the 1007fs Mutation and may be Explained by Age at Diagnosis: A Meta-Analysis and Case-Only Study

Background

NOD2 and smoking are risk factors for Crohn's disease. We meta-analyzed NOD2-smoking interactions in Crohn's disease (Phase 1), then explored the effect of age at diagnosis on NOD2-smoking interactions (Phase 2).

Methods

Phase 1: MEDLINE and EMBASE were searched for studies (n = 18) providing data on NOD2 and smoking in Crohn's disease. NOD2-smoking interactions were estimated using odds ratios (ORs) and 95% confidence intervals (CIs) calculated using random effects models. Phase 2: A case-only study compared the proportion of smokers and carriers of the 1007 fs variant across ages at diagnosis (≤ 16, 17–40, > 40 years).

Findings

Phase 1: Having ever smoked was less common among carriers of the 1007 fs variant of NOD2 (OR 0.74, 95%CI:0.66–0.83). There was no interaction between smoking and the G908R (OR 0.96, 95%CI:0.82–1.13) or the R702W variant (OR 0.89, 95%CI:0.76–1.05). Phase 2: The proportion of patients (n = 627) carrying the 1007 fs variant decreased with age at diagnosis (≤ 16 years: 15%; 17–40: 12%; > 40: 3%; p = 0.003). Smoking was more common in older patients (≤ 16 years: 4%; 17–40: 48%; > 40: 71%; p < 0.001).

Interpretation

The negative NOD2-smoking interaction in Crohn's disease is specific to the 1007 fs variant. However, opposing rates of this variant and smoking across age at diagnosis may explain this negative interaction.

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There is a negative interaction between NOD2 smoking in Crohn's disease and it is specific to the 1007fs variant.

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With increasing age, the prevalence of the 1007fs variant decreases and exposure to cigarette smoke increases.

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Contrasting trends in the 1007fs variant and cigarette smoking may explain the negative NOD2-smoking interaction.

We reviewed 18 studies evaluating NOD2-smoking interactions in Crohn's disease. Only the 1007fs variant interacted with smoking. Smokers with this mutation were less likely to develop Crohn's disease. We then conducted a study of 627 patients with Crohn's disease, which showed that the 1007fs variant was common in young patients and rare in older patients, whereas smoking was more common among older patients. The decreasing prevalence of 1007fs mutation and increasing exposure to smoking as age of diagnosis advances may explain the negative interaction between NOD2 and smoking observed in our meta-analysis. Our study highlights the challenges of identifying gene-environment interactions.

Genetic Influences on the Development of Fibrosis in Crohn's Disease

Fibrostenotic strictures are an important complication in patients with Crohn’s disease (CD), very often necessitating surgery. This fibrotic process develops in a genetically susceptible individual and is influenced by an interplay with environmental, immunological, and disease-related factors. A deeper understanding of the genetic factors driving this fibrostenotic process might help to unravel the pathogenesis, and ultimately lead to development of new, anti-fibrotic therapy. Here, we review the genetic factors that have been associated with the development of fibrosis in patients with CD, as well as their potential pathophysiological mechanism(s). We also hypothesize on clinical implications, if any, and future research directions.

Increasing incidence of pediatric inflammatory bowel disease in Spain (1996-2009): the SPIRIT Registry

BACKGROUND

Although pediatric inflammatory bowel disease (IBD) diagnosis has increased in the last decades in Spain, there are no consistent epidemiologic data. Our aim was to describe the changing pattern of pediatric IBD incidence in Spain in the last 14 years.

METHODS

A retrospective survey of patients diagnosed below 18 years of age in the period 1996-2009 was performed. Patients' data were obtained from the hospitals' databases. To avoid reduced accrual of cases diagnosed by adult physicians, adult IBD units in referral centers were invited to participate. Seventy-eight centers participated in our survey. Rates of incidence were calculated using age-stratified population-based epidemiologic data. Incidence rates were compared for the last 14 years (1996-2009).

RESULTS

In total, data from 2107 patients were obtained: 1,165 Crohn's disease (CD, 55.3%), 788 ulcerative colitis (UC, 37.4%), and 154 IBD unclassified. The sex distribution was 56.4% male, with higher predominance for CD (59.3%) as compared to UC (52.8%) and IBD unclassified (53.2%) (P = 0.012). The median age at diagnosis was 12.3 years (p25-75 9.7-14.6) with significant differences between diseases. IBD incidence increased from 0.97 to 2.8/100,000 inhabitants <18 years/year in the study period. Although this increase is more evident for CD (from 0.53 to 1.7), UC has also risen considerably (0.39 to 0.88).

CONCLUSIONS

This is the first attempt to calculate the current incidence of pediatric IBD in Spain. A significant increase of incidence rates in the study period was observed. In the last 14 years pediatric IBD incidence has almost tripled, with a more important CD increase.

The prognostic power of the NOD2 genotype for complicated Crohn's disease: a meta-analysis

OBJECTIVES

Crohn's disease is often purely inflammatory at presentation, but most patients develop strictures and fistulae over time (complicated disease). Many studies have suggested that nucleotide-binding oligomerization domain 2 (NOD2) mutations are associated with a varying but increased risk of complicated disease. An accurate and sufficiently powerful predictor of complicated disease could justify the early use of biological therapy in high-risk individuals. We performed a systematic review and meta-analysis to obtain accurate estimates of the predictive power of the identified mutations (such as p.R702W, P.G908R, and p.Leu1007fsX1008) in NOD2 for the risk of complicated disease.

METHODS

An electronic search of MEDLINE, Embase, and Web of Science identified 917 relevant papers. Inclusion required specification of genetic mutations at the individual level and disease phenotypes by Vienna classification (inflammatory (B1), stricturing (B2), and fistulizing (B3)). A total of 49 studies met these criteria, which included 8,893 subjects, 2,897 of whom had NOD2 mutations. Studies were weighted by median disease duration. Studies not providing duration data were weighted at the level of the study with the shortest disease duration (3.9 years).

RESULTS

The relative risk (RR) of the presence of any NOD2 mutant allele for complicated disease (B2 or B3) was 1.17 (95% confidence interval (95% CI) 1.10-1.24; P<0.001). P.G908R was associated with an RR of complicated disease of 1.33 (95% CI 1.11-1.60; P=0.002). NOD2 did not predict perianal disease (P=0.4). The RR of surgery was 1.58 (95% CI 1.38-1.80; P<0.001). There was substantial heterogeneity across all studies (I(2)=66.7%). On the basis of logistic regression of these data, the sensitivity of any mutation in predicting complicated disease was 36% and specificity was 73%, with the area under the receiver operating characteristic curve 0.56.

CONCLUSIONS

The presence of a single NOD2 mutation predicted an 8% increase in the risk for complicated disease (B2 or B3), and a 41% increase with 2 mutations. Surgery risk is increased by 58% with any NOD2 mutation, whereas perianal disease was unchanged. The predictive power associated with a single NOD2 mutation is weak. The RR of any NOD2 mutations for complicated disease was only 17% across 36 studies. However, the presence of two NOD2 mutations had 98% specificity for complicated disease. These data provide insufficient evidence to support top-down therapy based solely on single NOD2 mutations, but suggest that targeted early-intensive therapy for high-risk patients with two NOD2 mutations might be beneficial, if prospective trials can demonstrate changes in the natural history in this subset of patients.

High prevalence of viable Mycobacterium avium subspecies paratuberculosis in Crohn’s disease

AIM: To examine the detection rate of viable Mycobacterium avium subspecies paratuberculosis (MAP) in patients with inflammatory bowel disease [Crohn’s disease (CD) and ulcerative colitis (UC)].

METHODS: Thirty patients with CD (15 with at least one NOD2/CARD15 mutation), 29 with UC, and 10 with no inflammatory bowel disease (IBD). were tested for MAP by polymerase chain reaction (specific IS900 fragment) and blood culture.

RESULTS: MAP DNA was detected in all original blood samples and 8-wk blood cultures (CD, UC and non-IBD). Positive MAP DNA status was confirmed by dot blot assays. All 69 cultures were negative by acid-fast Ziehl-Neelsen staining. Viable MAP, in spheroplast form, was isolated from the 18-mo blood cultures of all 30 CD patients, one UC patient, and none of the non-IBD controls. No association was found between positive MAP cultures and use of immunosuppressive drugs or CD-associated single nucleotide polymorphisms.

CONCLUSION: MAP is widely present in our area and MAP DNA can be recovered from the blood of CD, UC and non-IBD patients. However, MAP spheroplasts were only found in CD patients.

Extreme heterogeneity in CARD15 and DLG5 Crohn disease-associated polymorphisms between German and Norwegian populations

The first gene associated with Crohn disease (CD) has been identified as CARD15 (16q12). Three variants, R702W, G908R and 1007fsinsC are strongly and independently associated with the disease. A second gene, conveying a smaller risk for inflammatory bowel disease (IBD), has been identified as DLG5 (10q23). We assess the frequency of the CARD15 SNPs and of the R30Q mutation in DLG5 and their contribution to the development of CD in a cohort of unrelated IBD patients (151 CD, 325 ulcerative colitis (UC)) and healthy controls (236) from South-east Norway (IBSEN cohort). Genotype-based tests of population differentiation using 23 SNPs across CARD15, together with estimates of F(ST), indicated that the German and Norwegian background populations could be differentiated at the CARD15 locus. The Norwegian and German CD samples exhibited particularly strong differentiation at the three predisposing loci and those marking their background haplotype. There were significantly lower frequencies of the CARD15 SNPs and no significant association with CD in the Norwegian samples. Only a marginal association was observed for the subphenotypes ileitis and ileocolitis vs colitis (P=0.048). The population attributable risk percentage (PAR%) for CARD15 variants in the Norwegian cohort is the lowest reported for a European population (1.88%), except Iceland. Similarly, the DLG5 variant showed no association with CD or IBD, however, there was a negative correlation with stricture (P=0.035). The present results are consistent with an emerging pattern of a low frequency of the CARD15 variants in Northern countries where the prevalence of IBD is greatest.

Disease behavior in children with Crohn's disease: the effect of disease duration, ethnicity, genotype, and phenotype

BACKGROUND

Disease behavior in Crohn's disease (CD) may be modified by disease location and genotype. Disease behavior may change over time, and thus analysis requires follow-up. To date, there have been few pediatric studies that have evaluated the association between disease behavior and genotype with prolonged follow-up. The aim of our study was to evaluate the effect of genotype, phenotype, and ethnicity on disease behavior in pediatric CD.

METHODS

Evaluation of 128 pediatric CD was followed by analysis of 232 pediatric and adult-onset CD patients. Inclusion required at least 2 years of follow-up. Phenotype, ethnicity, and disease duration were recorded. Patients were genotyped for polymorphisms in the NOD2/CARD15 gene.

RESULTS

Colonic involvement was more frequent in younger patients. Pediatric disease at end of follow-up was classified as inflammatory (78%), penetrating (7%), and stricturing (17%). Duration of follow-up (mean 4.9 pediatric and 6.4 years mixed) was associated with more stricturing and penetrating disease. There was no association between mean age of onset and NOD2/CARD15, or either of these with disease behavior. These observations were replicated in the mixed cohort. Sephardic Jewish origin was inversely correlated with inflammatory behavior (P = 0.006), independent of NOD2/CARD15 genotype.

CONCLUSIONS

Duration of disease and ethnicity, irrespective of NOD2/CARD15 genotype and age of onset, were the only predictors for penetrating or stricturing disease.

Perianal disease predicts changes in Crohn's disease phenotype-results of a population-based study of inflammatory bowel disease phenotype

BACKGROUND

The Montreal classification system of inflammatory bowel disease (IBD) provides a framework for describing disease phenotype.

OBJECTIVE

We aimed to describe changes in IBD phenotype using the Montreal system and determine predictors of phenotype change in a Caucasian population-based cohort.

METHODS

Ninety-two percent of people with IBD in Canterbury, New Zealand were recruited. Clinical notes were reviewed to confirm diagnosis and phenotype. Determinants of phenotype change were analyzed using multivariate analysis.

RESULTS

A total of 1,420 (715 Crohn's disease [CD], 668 ulcerative colitis [UC]) patients with IBD were included. Median follow-up was 6.5 and 10.9 yr for CD and UC, respectively. Disease location remained stable in 91% of those with CD. Seventy-three percent of CD patients had inflammatory disease at diagnosis with the proportion of patients with complicated disease increasing over time. Progression to complicated disease was more rapid in those with small bowel than colonic disease location, (P < 0.001). Perianal disease was a significant predictor of change in CD behavior (HR 1.62, P < 0.001). Younger UC patients were more likely to have extensive disease at diagnosis than older patients (P < 0.001).

CONCLUSIONS

Although CD location remains relatively stable, behavior changes over time. Perianal disease is a strong predictor of developing more complicated CD. Proctitis is most common in UC patients at diagnosis although younger patients are more likely than older patients to have extensive disease. The Montreal classification provides a clinically useful framework for both researchers and clinicians.

CARD15 gene polymorphisms in Serbian patients with Crohn's disease: genotype-phenotype analysis

OBJECTIVE

Genetic heterogeneity and incomplete phenotype penetrance complicate genetic analysis of Crohn's disease (CD). Studies in western Europe have shown that CARD15 polymorphisms increase susceptibility to CD, but frequencies vary within different European populations. The aim here was to evaluate the prevalence of CARD15 mutations and their phenotypic correlation in a Serbian population.

MATERIALS AND METHODS

131 patients with CD, 65 patients with ulcerative colitis, and 88 healthy controls were genotyped for three common mutations (R702W, G908R, Leu1007insC) by PCR-restriction fragment length polymorphism. chi and Student's t-test were used for statistical assessment.

RESULTS

At least one CARD15 disease-associated allele was found in 35.11% patients with CD, 14.77% of healthy controls (P=0.001), and 7.69% patients with ulcerative colitis (P=0.0001). The L1007fs mutation showed a significant association with CD (P<0.0001). The frequency of R702W mutant allele was almost equal in the control group and CD patients Univariate analyses established that CARD15 carriers had a significantly higher risk of isolated ileal location [P=0.042; odds ratio (OR) 2.30; 95% confidence interval (CI): 1.02-5.19], fibrostenotic behavior (P<0.0001; OR 9.86; 95% CI: 4.29-22.62), surgical resection (P=0.036; OR 2.2; CI, 1.046-4.626), and earlier onset of disease (P=0.026).

CONCLUSION

This study confirms that CARD15 carriers, especially L1007fs mutants, in central Europeans have an increased risk of CD and it is associated with earlier onset, ileal, fibrostenotic disease and a higher risk of surgery. Any influence of latitude is not matched by an east-west divide on the genotype frequency and phenotype of CD within Europe.

Variants of CARD15, TNFA and PTPN22 and susceptibility to Crohn's disease in the Czech population: high frequency of the CARD15 1007fs

Crohn's disease (CD) has been shown to be associated with the variants in the CARD15 gene as well as in other genes involved in the immune response. The frequencies of the variants profoundly differ among populations and so does the associated risk. We examined the associations of variants in the CARD15, TNFA and PTPN22 genes with pediatric-onset and adult-onset CD in the Czech population. Genotype, phenotype and allelic frequencies were compared between 345 patients with CD (136 pediatric-onset and 209 adult-onset patients) and 501 unrelated healthy controls. At least one minor allele of the CARD15 gene was carried by 46% patients and only 21% control subjects (OR = 3.2, 95% CI 2.4-4.4). In a multiple logistic regression model, the strongest association with CD was found for the 1007fs variant (OR = 4.6, 95% CI 3.0-7.0), followed by p.G908R (OR = 2.9, 95% CI 1.5-5.7) and p.R702W (OR = 1.7, 95% CI 1.0-2.9), while no independent association was found for the remaining variants in the CARD15 gene (p.268S, p.955I and p.289S), for the p.R620W variant in the PTPN22 gene or for the g.-308G>A variant in the TNFA gene. The age at CD onset was strongly modified by positivity for the 1007fs allele: it was present in 42% pediatric-onset and only 25% adult-onset patients. In conclusion, we report a high frequency of the minor allele of the CARD15 1007fs polymorphism in the Czech population and a strong effect of this allele on the age at disease onset.

Mutations in CARD15 and smoking confer susceptibility to Crohn's disease in the Danish population

OBJECTIVE

Three CAspase Recruitment Domain (CARD15) mutations have shown to predispose to Crohn's disease in Caucasian populations. The aim of this study was to investigate the mutation frequency in patients with inflammatory bowel disease and in healthy controls in Denmark.

MATERIAL AND METHODS

Genotyping of the three common CARD15 mutations was carried out on 388 patients with Crohn's disease, 565 patients with ulcerative colitis and 796 healthy controls using real-time PCR. Allele and genotype frequencies in the three groups were compared. A possible additive effect of smoking on CARD15 mutations was also examined.

RESULTS

Carrying at least one CARD15 mutation was significantly more common in patients with Crohn's disease compared with healthy controls (21% versus 10%; p <0.001). A gene-dosage effect was observed (ORadj.smoking 22.2; p <0.001 for carrying two CARD15 mutations versus ORadj.smoking 1.8; p=0.01 for carrying one CARD15 mutation). The 1007insC protein truncating mutation was the major contributing mutation. Ileal involvement was more common in Crohn's disease patients with CARD15 mutations as opposed to patients without CARD15 mutations (ORadj.smoking 3.6; p <0.001). Smoking was independently associated with Crohn's disease (OR 1.8; p <0.001), but no multiplicative effect of smoking on CARD15 genotypes was found.

CONCLUSIONS

In the Danish population, CARD15 mutations were found to be associated with Crohn's disease, hence supporting the hypothesis of a genetic component contributing to the disease. Further research for other genes possibly involved in Crohn's disease may result in the use of genetic testing for diagnosis or treatment of Crohn's disease in the future.

Influence of a nucleotide oligomerization domain 1 (NOD1) polymorphism and NOD2 mutant alleles on Crohn's disease phenotype

AIM: To examine genetic variation of nucleotide oligomerization domain 1 (NOD1) and NOD2, their respective influences on Crohn's disease phenotype and gene-gene interactions.

METHODS: (ND₁+32656*1) NOD1 polymorphism and SNP8, SNP12 and SNP13 of NOD2 were analyzed in 97 patients and 50 controls. NOD2 variants were determined by reaction restriction fragment length polymorphism analysis. NOD1 genotyping and NOD2 variant confirmation were performed by specific amplification and sequencing.

RESULTS: The distribution of NOD1 polymorphism in patients was different from controls (P = 0.045) and not altered by existence of NOD2 mutations. In this cohort, 30.92% patients and 6% controls carried at least one NOD2 variant (P < 0.001) with R702W being the most frequent variant. Presence of at least one NOD2 mutation was inversely associated with colon involvement (9.09% with colon vs 36.4% with ileal or ileocolonic involvement, P = 0.04) and indicative of risk of penetrating disease (52.63% with penetrating vs 25.64% with non-penetrating or stricturing behavior, P = 0.02). L1007finsC and double NOD2 mutation conferred the highest risk for severity of disease (26.3% with penetrating disease vs 3.8% with non-penetrating or stricturing behavior presented L1007finsC, P = 0.01 and 21.0% with penetrating disease vs 2.5% with non-penentrating or stricturing behavior carried double NOD2 mutation, P = 0.007). Exclusion of patients with NOD2 mutations from phenotype/NOD1-genotype analysis revealed higher prevalence of *1*1 genotype in groups of younger age at onset and colonic location.

CONCLUSION: This study suggests population differences in the inheritance of risk NOD1 polymorphism and NOD2 mutations. Although no interaction between NOD1-NOD2 was noticed, a relationship between disease location and Nod-like receptor molecules was established.

Prevalence of CARD15/NOD2 mutations in Caucasian healthy people

BACKGROUND

Crohn's disease (CD) has been associated with CARD15/NOD2 mutations in Caucasians. The R702W, G908R, and 1007fs mutations represent 82% of the mutated chromosomes. The relative risk of developing CD in homozygous or compound heterozygous people has been estimated as between 10 and 40 times that of the general population. This high risk may support the opinion that CARD15/NOD2 variants are strong CD risk factors at the individual and population levels.

SUBJECTS AND METHODS

The allele and genotype frequencies were calculated for the R702W, G908R, and 1007fs mutations in 3,575 Caucasian healthy controls recruited by 15 groups distributed on three continents. Geographic homogeneity was tested and the observed proportion of double mutants was compared with the expected value using chi2 tests.

RESULTS

The allele frequencies of the R702W, G908R, and 1007fs mutations were 4.3% (3.6-4.9), 1.2% (0.8-1.6), and 2.3% (1.8-2.8), respectively, with large geographic fluctuations of the G908R, 1007fs, and wild-type alleles (P<0.0001). At the population level, no simple relationship was observed between mutation frequencies and the disease incidences in the studied populations. At the individual level, no significant deficit of double-dose mutation carriers among healthy controls was found, providing strong evidence that the penetrances of the most at-risk genotypes are low.

CONCLUSION

Altogether, these data confirm that CARD15/NOD2 acts in interaction with other unknown risk cofactors.

CARD15 mutations in Dutch familial and sporadic inflammatory bowel disease and an overview of European studies

OBJECTIVES

The single nucleotide variations R702W, G908R and L1007fs in the CARD15 gene have been found to be independently associated with Crohn's disease. The aim of this study was to evaluate the prevalence of these gene variations in Dutch multiple inflammatory bowel disease-affected families, in sporadic inflammatory bowel disease patients and in healthy controls.

METHODS

Dutch Caucasians from multiple inflammatory bowel disease-affected families were recruited, including 78 probands with Crohn's disease, 34 probands with ulcerative colitis and 71 inflammatory bowel disease-affected and 100 non-affected family members. In addition, 45 sporadic inflammatory bowel disease patients (36 Crohn's disease and nine ulcerative colitis), and 77 unrelated healthy controls were included. Genomic DNA was isolated to determine CARD15 R702W, G908R and L1007fs. For these mutations, we evaluated disease susceptibility and correlation with inflammatory bowel disease phenotypes.

RESULTS

In all included unrelated inflammatory bowel disease-affected probands, the R702W, G908R and L1007fs allele frequencies were 8.8, 6.1 and 11.0%, respectively, for Crohn's disease, and 4.7, 0 and 2.3% for ulcerative colitis. In controls, the allele frequencies were 5.9, 0.7 and 1.9%, respectively. G908R and L1007fs were associated with Crohn's disease (P=0.006 and 0.001, respectively). Compound heterozygotes for any of the three mutations were 11 (9.2%) in Crohn's disease patients, but none in ulcerative colitis patients nor controls. Carriage of CARD15 mutations was not associated with familial disease (P>or=0.38). Inflammatory bowel disease-affected family members of Crohn's disease probands carrying L1007fs, however, were carriers significantly more often than expected (P<0.001). In Crohn's disease patients, a significant trend was found between carriage of at least one CARD15 mutation and between carriage of L1007fs and behaviour of disease, including more carriers with stricturing and even more with penetrating disease (P=0.006 and 0.017, respectively).

CONCLUSION

In the Dutch population, CARD15 G908R and L1007fs are associated with Crohn's disease. Although no difference was found between sporadic and familial cases, in L1007fs-positive multiple affected families the inflammatory bowel disease-affected relatives are more likely than expected to carry this mutation. In Crohn's disease, carriage of at least one CARD15 mutation is associated with a more complicated disease behaviour.

Plasma carnitine ester profiles in Crohn's disease patients characterized for SLC22A4 C1672T and SLC22A5 G-207C genotypes

Crohn's disease (CD) is a chronic inflammatory bowel disorder caused by environmental and genetic factors. The purpose of this study was to analyse the possible influence of functional variants of genes of OCTN cation transporters on the carnitine ester profile of patients with CD. Genotyping for SLC22A4 1672C --> T, SLC22A5-207G --> C mutations and three common NOD2 variants (R702W, G908R and 1007finsC) were performed in 100 adult CD patients and in ninety-four healthy controls by direct sequencing. The carnitine ester profile was determined using ESI triple quadrupole tandem MS. Contrary to the NOD2/CARD15 mutations, none of the SLC variants showed increased prevalence in the CD group, the prevalence of TC haplotype did not differ between the patients and the controls. In the mixed group of CD patients the fasting propionyl- (0.243 (sem 0.008) v. 0.283 (sem 0.014) micromol/l), butyryl- (0.274 (sem 0.009) v. 0.301 (sem 0.013)) and isovalerylcarnitine (0.147 (sem 0.006) v. 0.185 (sem 0.009)) levels were decreased; while the level of octenoyl- (0.086 (sem 0.006) v. 0.069 (sem 0.005)), myristoleyl- (0.048 (sem 0.003) v. 0.037 (sem 0.003)), palmitoyl- (0.140 (sem 0.005) v. 0.122 (sem 0.004)) and oleylcarnitine (0.172 (sem 0.006) v. 0.156 (sem 0.008); P < 0.05 in all comparisons) were increased. After sorting the patients into SLC22A genotype-specific subgroups, no significant differences could be observed between them. The carnitine ester profile data suggest selective involvement of the carnitine esters in CD patients, probably due to their altered metabolism.

Association of NOD2/CARD15 mutations on Crohn's disease phenotype in an Italian population

AIMS

To confirm the prevalence of NOD2/CARD15 mutations in Italian inflammatory bowel disease patients and to define the role of the different mutations on Crohn's disease phenotype.

PATIENTS AND METHODS

A total of 177 patients with Crohn's disease and 92 patients with ulcerative colitis and 164 control participants were investigated for the presence of Arg702Trp, Gly908Arg and Leu1007fsinsC NOD2/CARD15 mutations. Allele frequencies in Crohn's disease and ulcerative colitis patients were compared with those observed in the control population. Genotype-phenotype correlations with the major clinical features were also established and estimated risks (odds ratio with 95% confidence interval) for the mutations were calculated by logistic regression and multiple correspondent analysis.

RESULTS

Gly908Arg and Leu1007fsinsC mutations were significantly more frequent in Crohn's disease patients compared with healthy controls (P<0.01 and <0.003 respectively). Indeed, using a logistic regression model adding terms for age (differently distributed between cases and controls) and sex, a significantly increased risk of having Crohn's disease compared with healthy controls was found for all NOD2 mutations: Leu1007fsinsC (odds ratio=7.35; 95% confidence interval: 1.73-31.3), Gly908Arg (odds ratio=5.70; 95% confidence interval: 1.37-23.7) and Arg702Trp (odds ratio=2.45; 95% confidence interval: 1.10-5.47). As far as the genotype-phenotype correlations are concerned, by multivariate conditional logistic regression methods, we found a significant association between Gly908Arg mutations and familial history of inflammatory bowel disease, between Leu1007fsinsC mutations and appendectomy and between Arg702Trp mutations and fibrostenotic phenotype of Crohn's disease. A nonsignificant association between Arg702Trp variants and ileal disease was also found (odds ratio=8, 95% confidence interval: 0.99-64.9).

CONCLUSIONS

The results of the study confirm a significant association of CARD15 gene mutations in our Italian Crohn's disease population and the impact of different NOD2/CARD15 mutations on specific disease phenotypes.

A population-based case-control study of CARD15 and other risk factors in Crohn's disease and ulcerative colitis

OBJECTIVES

Multiple established Crohn's disease (CD) and ulcerative colitis (UC) risk factors including family history, tobacco use, Jewish ethnicity, urban residency, and CARD15/NOD2 mutations have been evaluated singly and in hospital-based observational studies. The goal of this study was to assess the relative contributions of all these risk factors jointly in a nonreferral, population-based cohort derived from a population epidemiologic database.

METHODS

CD (N = 232) and UC (N = 121) subjects were ascertained from our population-based IBD Registry derived from Manitoba Health, the single provincial insurer. Healthy controls (HC) (N = 336) were recruited via a 10:1 mailing matched for age, sex, and postal code. Ethnicity, tobacco use, family history, residency, and CARD15/NOD2 genotype status were determined.

RESULTS

In both univariate analyses and analyses adjusted for all risk factors, CD was influenced independently by CARD15/NOD2 heterozygote and homozygote/compound-heterozygote status (adjusted odds ratios [OR] 3.7 and 40.0, respectively), Jewish ethnicity (OR 18.5), CD family history (OR 6.2), and smoking (OR 3.0 current and 1.7 ex-smoker, respectively). Penetrance for homozygote/compound-heterozygotes was 4.9%, heterozygotes 0.54%, and wild types 0.184%. Population attributable risk for CARD15 was 26.7% and current tobacco use was 46.8%. A tobacco-CARD15 interaction was not observed. UC was influenced by Jewish ethnicity (OR 37.1), and by family history (OR 2.6), ex-smoker status (OR 1.9), and CARD15/NOD2 heterozygote or homozygote/compound-heterozygote status (OR 1.9 and 6.4, respectively) in adjusted analyses only.

CONCLUSIONS

CARD15/NOD2, family history, smoking, and Jewish ethnicity are independent risk factors for CD. Examination of these risk factors together in a single population-based cohort has provided initial data for population epidemiological characterization and genetic counseling uses.

The prevalence of genetic and serologic markers in an unselected European population-based cohort of IBD patients

BACKGROUND AND AIM

The aetiology of inflammatory bowel disease (IBD) is unknown, but it has become evident that genetic factors are involved in disease susceptibility. Studies have suggested a north-south gradient in the incidence of IBD, raising the question whether this difference is caused by genetic heterogeneity. We aimed to investigate the prevalence of polymorphisms in CARD15 and TLR4 and occurrence of anti-Saccharomyces cerevisiae (ASCA) and antineutrophil cytoplasmic antibodies (pANCA) in a European population-based IBD cohort.

METHODS

Individuals from the incident cohort were genotyped for three mutations in CARD15 and the Asp299gly mutation in TLR4. Levels of ASCA and pANCA were assessed. Disease location and behaviour at time of diagnosis was obtained from patient files.

RESULTS

Overall CARD15 mutation rate was 23.9% for CD and 9.6% for UC patients (P < 0.001). Mutations were less present in the Scandinavian countries (12.1%) versus the rest of Europe (32.8%) (P < 0.001). Overall population attributable risk was 11.2%. TLR4 mutation rate was 7.6% in CD, 6.7% in UC patients and 12.3% in healthy controls (HC), highest among South European CD patients and HC. ASCA was seen in 28.5% of CD patients with no north-south difference, and was associated with complicated disease. pANCA was most common in North European UC patients and not associated with disease phenotype.

CONCLUSION

The prevalence of mutations in CARD15 varied across Europe, and was not correlated to the incidence of CD. There was no association between mutations in TLR4 and IBD. The prevalence of ASCA was relatively low; however related to severe CD.

Incidence of Crohn’s disease and CARD15 mutation in a small township in Sicily

BACKGROUND

The incidence of Crohn's disease (CD) has been shown to be lower in Southern than in Northern Europe. Data on the frequency of the NOD2/CARD15 mutations for Mediterranean area are very scant.

AIM

To determine the incidence of CD from 1979 to 2002 in a township in Sicily together with the allele frequency of NOD2/CARD15 mutations in patients, family members and controls, and to determine the allele frequency of these mutations in sporadic CD from other areas of Sicily in comparison with a control population.

METHODS

Casteltermini is a small town close to Agrigento (Sicily) with a population of 9,130 inhabitants. All the diagnoses of inflammatory bowel disease (IBD) made from 1979 to 2002 were obtained through the local health authority. NOD2/CARD15 mutations were studied in 23 out of the 29 patients with CD in Casteltermini, in 60 family members and in 64 controls. NOD2/CARD15 was also studied in 80 sporadic cases of CD disease among Sicilians outside Casteltermini and 118 healthy controls.

RESULTS

From 1979 to 2002, 29 patients with CD and 13 patients with ulcerative colitis (UC) were registered. The 6-year mean incidence of CD ranged from 8.0 to 17 new cases for every 100,000 inhabitants, whereas the mean incidence of UC ranged from five new cases to 7.8 for every 100,000 inhabitants. The allele frequencies of NOD2/CARD15 mutations (L1007finsC, G908R, R702W) were 8.7, 4.3 and 8.7%, respectively, in CD cases; 5.0, 4.2 and 3.1% in family members; 1.6, 2.3 and 3.1% in controls. In sporadic Sicilian CD patients outside Casteltermini the allele frequency was 7.5, 8.1, 6.2% whereas in control population it was 3.3, 1.6, 1.6%.

CONCLUSIONS

A high incidence of CD compared with UC was observed in this small town in Southern Italy. The frequency of NOD2/CARD15 mutations in CD is similar to other Caucasian population studied so far.

Associations between NOD2/CARD15 genotype and phenotype in Crohn’s disease-Are we there yet?

There have been multiple NOD2/CARD15 genotype-phenotype analyses undertaken in patients with Crohn's disease since the gene’s discovery in 2001. This review focuses on the major published series based upon their size and on the presence of specific clinical and genetic information provided in the published material from 2001 to 2005. Twelve studies provided raw data to carry out comparisons of disease location while ten studies included analysis of NOD2/CARD15 genotypes. NOD2/CARD15 variant frequency in ileal disease did not differ significantly among studies, whereas a comparison of disease location demonstrated highly significant differences among studies. Meta-analysis confirmed significant associations between NOD2/CARD15 variants and both ileal and ileocolonic disease locations, and with both stricturing and penetrating forms of disease behavior. This review underlines the significant phenotypic differences that exist among populations, including similar ethnic groups, and has demonstrated the need for further studies of patients with long-term “inflammatory” Crohn’s disease.

CARD15 in inflammatory bowel disease and Crohn's disease phenotypes: an association study and pooled analysis

BACKGROUND

Three major polymorphisms of the Caspase-Activation Recruitment Domain containing protein 15 gene have been described to be associated with Crohn's disease. Genotype-phenotype studies reported in literature provide conflicting data on disease localisation and behaviour. We investigated the relation of Caspase-Activation Recruitment Domain containing protein 15 with inflammatory bowel disease and Crohn's disease phenotypic characteristics in a large Dutch cohort and performed a pooled analysis on inflammatory bowel disease patients and Crohn's disease phenotypic characteristics reported in association studies.

METHODS

We genotyped 781 cases and 315 controls for the R702W, G908R and 1007fsinsC variants and for six microsatellite markers in and close to Caspase-Activation Recruitment Domain containing protein 15. In the pooled analysis data of 7201 inflammatory bowel disease patients and 3720 controls from 20 studies were included.

RESULTS

Association was found for Crohn's disease with R702W and 1007fsinsC, including several disease characteristics, and not for ulcerative colitis. In the pooled analysis all three common Caspase-Activation Recruitment Domain containing protein 15 variants showed strong association with Crohn's disease (p<0.00001; odds ratio varying from 3.0 for single heterozygotes to 14.7 for compound heterozygotes) and not with ulcerative colitis. Phenotype analysis showed association with small bowel involvement, stricturing and penetrating disease.

CONCLUSION

Caspase-Activation Recruitment Domain containing protein 15 is associated with Crohn's disease and not with ulcerative colitis. All three common Crohn's disease-associated variants are associated with small bowel involvement, the G908R and 1007fsinsC alleles also being associated with a complicated disease course.

Review article: genetic susceptibility and application of genetic testing in clinical management of inflammatory bowel disease

The volume of research undertaken on the genetic susceptibility of inflammatory bowel disease (IBD) has been tremendous, and over 10 chromosomal regions have been identified by genome-wide scanning. Fine-mapping approaches and candidate gene studies have already led to the identification of several susceptibility genes, including CARD15 (NOD2), DLG5, novel organic cation transporter (OCTN) 1 and 2, and CARD4 (NOD1). The CARD15 gene is the most understood at present and explains around 20% of the genetic predisposition to Crohn's disease. Although the clinical implications of genetic testing are limited at present, genetic research has advanced our understanding of the clinical heterogeneity and the complex interactions between genetic and environmental risk factors in IBD. Genes also interfere with the metabolism of drugs and may influence the clinical response and drug-related toxicity. Ultimately, researchers and clinicians aim to personalize medicine based on a patient's genotype, although azathioprine (thiopurine methyltransferase polymorphisms) is the only drug to date where pharmacogenetics has shown clinical relevance in IBD. In the future, it is anticipated that genetic markers will be implemented in an integrated molecular diagnostic and prognostic approach to managing our patients.

TNFalpha genotype influences development of IgA-ASCA antibodies in Crohn's disease patients with CARD15 wild type

A typical feature of Crohn's disease (CD) patients is the development of antibodies against self- (PAB) or exogenous (ASCA) antigens, a process in which mucosal cytokine expression pattern might be involved. On the other hand, mutations in CARD15, a genetic risk factor for CD, alter cytokine production in response to bacterial infection. In the present study, we evaluated the role of functionally relevant IL-10 and TNFalpha gene polymorphisms in the synthesis of these antibodies and their relationship with CARD15 mutations. In CARD15 wild type patients, high TNFalpha producer genotypes protect against IgA-ASCA development, whereas an inverse association was observed in autoantibody synthesis (PAB). These associations were not observed in patients with CARD15 mutations, probably due to the lack of TNFalpha release as a consequence of the failure of CARD15 protein to recognize the peptidoglycan. Thus, we proposed a CARD15-TNFalpha circuit that might play a role in mucosal immune surveillance.

Frequency of CARD15 Polymorphisms in Patients with Crohn's Disease from Toledo, Spain: Genotype–Phenotype Correlation

Crohn's disease (CD) presents a complex multifactorial etiology with genetic and environmental factors contributing to the disorder. Epidemiological studies have shown that three major CARD15 polymorphisms, R702W, G908R, and 1007fs, are associated with CD. We studied the frequencies of these three polymorphisms in patients from Toledo, Spain, and compared them with the frequencies found in studies of other populations. A total of 183 patients with CD and 172 healthy controls from Toledo, Spain, were included in this study. All of these individuals were genotyped for the three CARD15 polymorphisms R702W, G908R, and 1007fs. Frequencies were analyzed to identify any genotype-phenotype associations. The control population exhibited frequencies of CARD15 polymorphisms similar to the results of previous studies, 3.4%, 1.1%, and 2.0% for the R702W, G908R, and 1007fs polymorphisms, respectively, whereas CD patients had allele frequencies of 7.6%, 3.0%, and 4.6%, respectively. Significant associations were found between the presence of R702W and patients carrying two susceptibility variants with early age of onset and stricturing pattern.

Contribution of genetics to a new vision in the understanding of inflammatory bowel disease

Inflammatory bowel diseases (IBD), such as Crohn’s disease (CD) and ulcerative colitis (UC), are chronic inflammatory autoimmune conditions of the gastrointestinal tract. Other organs, such as the eyes, skin and articulations, are often affected and IBD may be accompanied by other diseases of autoimmune origin. There is no single etiological factor responsible for the onset of IBD. Recent advances in genetics and in the molecular mechanisms of the proteins coded by these genes have given rise to a new vision in understanding these complex diseases. Activation of specific genes that affect antigen presentation and the handling of cells by innate immunity may lead to autoimmunity with the consequent activation of the major histocompatibility complex (MHC) and multiple cytokines involved in the regulation of acquired immunity. In this review IBD is described as a constellation of diseases that can best be classified as barrier diseases. This vision, developed by Kiel in Germany, includes the idea that changes in our environment due to the westernization of civilization have not been met with adaptation of the innate immune system, and this has given rise to autoimmune diseases. These diseases affect 1-5 of 1000 individuals and represent a major burden on the national health systems of many countries on different continents. On a world scale, a major challenge is to generate interventions to prevent the development of these diseases in Asia, Latin America and Africa.

NOD2/CARD15 mutations in Croatian patients with Crohn's disease: prevalence and genotype-phenotype relationship

BACKGROUND

Crohn's disease (CD) is a chronic inflammatory disorder of the gastrointestinal tract with variations in localization and behaviour. Mutations in the NOD2/CARD15 gene on chromosome 16q have been implicated in the pathogenesis of the disease and three main sequence variants, all single nucleotide polymorphisms (SNPs), have been identified in North American and European populations.

AIMS AND METHODS

As no data exist in the Croatian population, we consecutively collected a cohort of 136 CD patients and 91 healthy controls to determine the prevalence of NOD2/CARD15 mutations and their association with phenotypic expression of the disease. All patients and controls were genotyped for Arg702Trp (Hugot SNP8), Gly908Arg (Hugot SNP12), and Leu1007fsinsC (Hugot SNP13) and allele frequencies were compared between the Crohn's patients and controls. The correlation of NOD2/CARD15 genotypes with the phenotypic expression of Crohn's disease was further assessed by logistic regression analysis.

RESULTS

NOD2/CARD15 variants were found in 38/136 CD patients (27.9%) compared to 10/91 (10.9%) healthy controls (P = 0.0022). Allele frequencies in patients with CD were 13.97%, 4.4% and 11.76%, respectively, for SNP8, 12 and 13, compared to 5.49%, 1.12% and 4.40% in controls (P = 0.041, P = 0.162, P = 0.055). Six CD patients carried double mutations and, remarkably, we identified two homozygous mutants amongst the healthy control group. Surgery over the course of the disease and a younger age at onset of the disease were significantly more frequent in patients who were carriers of NOD2/CARD15 mutations.

CONCLUSIONS

This report on NOD2/CARD15 mutations in Croatian patients with CD demonstrates that this gene is also implicated in susceptibility to CD in the Croatian population. Phenotypic association showed a younger age at diagnosis and a higher need for surgery in patients carrying NOD2/CARD15 mutations. However, the prevalence is somewhat lower compared to other reports, likely due to a more prominent colonic inflammation.

New genes in inflammatory bowel disease: lessons for complex diseases?

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.

Clinical outcome of Crohn's disease according to the Vienna classification: disease location is a useful predictor of disease course

OBJECTIVES

Crohn's disease (CD) is a complex genetic disease with multiple clinical patterns. Clinical classifications may help to identify subgroups of patients that have a distinct pattern of disease, and they are also a prerequisite for the conduction of genetic and therapeutic studies. The aim of this study was to determine the usefulness of the Vienna classification in patient care and clinical studies.

METHODS

The clinical data of patients were carefully reviewed retrospectively. The behaviour and location of the disease were determined according to the Vienna classification and additional clinical characteristics including surgical data, vitamin B12 status and medication were also assessed.

RESULTS

Data according to the Vienna classification of 292 CD cases were available. The mean age at diagnosis was 31.4 years. The operation rate was higher in patients with ileocolonic localization (P<0.05) and stricturing and penetrating disease behaviour (P<0.001). The incidence of vitamin B12 deficiency was 41.9% in cases with ileal involvement and 20.7% in cases with disease confined to the colon. In 187 cases (64.0%) an operation was performed because of CD-related complications, in a majority (126, 67.4%) this took place within 5 years after diagnosis. Intolerance of azathioprine occurred in 36 cases (22.0%).

CONCLUSIONS

Ileocolonic disease localization is associated with a complicated course of disease. Vitamin B12 deficiency occurs frequently, also in patients with disease apparently confined to the colon. We propose that location parameters can be used for the prediction of disease course in clinical settings and in interventional studies.

Polymorphisms in interleukin-10 gene according to mutations of NOD2/CARD15 gene and relation to phenotype in Spanish patients with Crohn’s disease

AIM: To examine the contribution of interleukin-10 (IL-10) gene polymorphisms to Crohn’s disease (CD) phenotype, and the possible genetic epistasis between IL-10 gene polymorphisms and CARD15/NOD2 gene mutations.

METHODS: A cohort of 205 Spanish unrelated patients with Crohn's disease recruited from a single center was studied. All patients were rigorously phenotyped and followed-up for at least 3 years (mean time, 12.5 years). The clinical phenotype was established prior to genotyping.

RESULTS: The correlation of genotype-Vienna classification groups showed that the ileocolonic location was significantly associated with the -1082G allele in the NOD2/CARD15 mutation-positive patients (RR = 1.52, 95%CI, 1.21 to 1.91, P = 0.008). The multivariate analysis demonstrated that the IL-10 G14 microsatellite allele in the NOD2/CARD15 mutation positive patients was associated with two risk factors, history of appendectomy (RR = 2.15, 95%CI = 1.1-4.30, P = 0.001) and smoking habit at diagnosis (RR = 1.29, 95%CI = 1.04-4.3, P = 0.04).

CONCLUSION: In Spanish population from Madrid, in CD patients carrying at least one NOD2/CARD15 mutation, the -1082G allele is associated with ileocolonic disease and the IL-10G14 microsatellite allele is associated with previous history of appendectomy and smoking habit at diagnosis. These data provide further molecular evidence for a genetic basis of the clinical heterogeneity of CD.

Current status of genetics research in inflammatory bowel disease

The research on genetic susceptibility of inflammatory bowel diseases (IBD) has been tremendous and over 10 chromosomal regions have been identified by genome-wide scanning. Further fine mapping as well as candidate gene studies have already led to the identification of a number of susceptibility genes including CARD15, DLG5, OCTN1 and 2, NOD1, HLA, and TLR4. The CARD15 gene is undoubtedly replicated most widely and most understood at present. CARD15 is involved in the recognition of bacterial peptidoglycan-derived muramyl dipeptide (MDP) and will stimulate secretion of antimicrobial peptides including alpha-defensins (also called cryptdins) to protect the host from invasion. Genetic research in IBD has advanced our understanding of the clinical heterogeneity of the disease and has started to tackle the complex interactions between genetic risk factors and environmental risk factors in IBD. Genes also interfere with the metabolization of drugs and may influence the clinical response and the drug-related toxicity. Interesting pharmacogenetic data with respect to steroids, azathioprine, and infliximab have been generated in IBD. Overall, it is anticipated that genetic markers in the future will be implemented in an integrated molecular diagnostic and prognostic approach of our patients.

MDR1 gene: susceptibility in Spanish Crohn's disease and ulcerative colitis patients

BACKGROUND

The multidrug resistance MDR1 gene codes for a membrane transporter associated with inflammatory bowel disease. The polymorphism Ala893Ser/Thr (G2677T/A) previously showed significant association with Crohn's disease (CD) and the Ile1145Ile (C3435T) with ulcerative colitis (UC). We studied the association of both polymorphisms in an independent population to reveal the impact of the MDR1 gene on predisposition to inflammatory bowel disease.

METHODS

Case-control study with 321 CD and 330 UC white Spanish patients recruited from the same center, and 352 healthy ethnically matched controls.

RESULTS

A significant association of MDR1 C3435T with CD was observed (CC vs (CT + TT): P = 0.007; OR [95% CI] = 1.58 [1.12-2.23]). A CD susceptibility haplotype 2677T/C3435 was identified. No difference between UC patients as a whole and controls could be detected.

CONCLUSIONS

New evidence supports the role of the MDR1 gene on CD susceptibility. Therefore, considering our results and those from others, the MDR1 gene behaves as a common risk factor for both CD and UC. We discovered that the C3435 allele conferring susceptibility to CD is different from the described 3435T UC risk allele.

Relevance of the phenotypic characteristics of Crohn's disease in patient perception of health-related quality of life

BACKGROUND

Crohn's disease (CD) has a negative impact on patients' perception of health. Several factors, such as disease activity, influence HRQOL impairment. However, the effect of the phenotypic CD characteristics recognized in the Vienna classification on health-related quality of life (HRQoL) remains unknown.

METHODS

HRQOL was measured in CD patients using three questionnaires: the Spanish version of the Inflammatory Bowel Disease Questionnaire (IBDQ-36), the Psychological General Well-Being Index (PGWBI), and the EuroQol.

RESULTS

One hundred ninety-eight CD patients were included. Scores for the IBDQ-36, PGWBI, and EuroQol dimensions did not differ according to age at diagnosis (177 patients under 40 yr and 21 over 40 yr), disease location (53 in terminal ileum, 62 in colon, 72 in ileocolon, and 11 in upper gastrointestinal tract) or disease behavior (99 nonstricturing-nonpenetrating, 32 stricturing, and 67 penetrating). Multivariate analysis identified as significant independent variables for worse HRQoL: female sex (t: -3.70), higher number of relapses per year (t: -2.71), and worse clinical disease activity (t: -7.82). None of the three Vienna variables reached statistical significance.

CONCLUSIONS

HRQoL impairment in CD patients is independent of the clinical variables established in the Vienna classification for phenotypic type of disease.

Association of organic cation transporter risk haplotype with perianal penetrating Crohn's disease but not with susceptibility to IBD

BACKGROUND & AIMS

Three years after the identification of NOD2/CARD15, 2 more genes for inflammatory bowel diseases (IBDs) were reported. The carnitine/organic cation transporter (OCTN) on 5q31 (IBD5) is associated with Crohn's disease (CD) and DLG5 (10q23), a member of membrane-associated guanylate kinase (MAGUK) family, with IBD. We studied mutation prevalence, assessed phenotypic expression, and performed conditional analysis to examine evidence for gene-gene interactions.

METHODS

A cohort of 2032 individuals was genotyped for disease-associated OCTN and DLG5 variants, including 981 patients with IBD (CD, n = 769; ulcerative colitis, n = 186; indeterminate colitis, n = 26) followed up at a tertiary IBD center. For 373 patients, DNA from both parents was available (cohort 1) for transmission disequilibrium testing analysis; case-control analysis was performed in 608 patients and 305 controls (cohort 2).

RESULTS

There was no distortion of transmission toward affected offspring for any of the variant alleles. Case-control analysis also failed to shown an association. A higher frequency of DLG5 113A was observed in CARD15-positive patients (12.2%) compared with CARD15-negative patients (8.7%; P = .033). The OCTN-TC risk haplotype was associated with penetrating disease (odds ratio, 1.474; 95% confidence interval, 1.028-2.114; P = .035). For DLG5, there were no associations with a particular phenotype.

CONCLUSIONS

DLG5 and OCTN do not play a role in the susceptibility to IBD, CD, or ulcerative colitis in the Flemish population but play a role in the phenotypic expression of the disease. OCTN variants were associated with perianal and penetrating CD. More studies in independent populations are urgently needed to assess the validity of DLG5 and OCTN in the pathogenesis of IBD.

[Extraintestinal manifestations in inflammatory bowel disease: differences between Crohn's disease and ulcerative colitis]

BACKGROUND AND OBJECTIVE

The true prevalence of the extraintestinal manifestations (EM) associated with inflammatory bowel disease (IBD) may vary depending on the geographic area, IBD population, location and duration of the disease, medication and diagnostic accuracy. The aim of this study was determine the prevalence of the major EM of IBD and their differences between Crohn's disease (CD) and ulcerative colitis (UC).

PATIENTS AND METHOD

A prospective study with a total of 566 patients (295 CD with median follow up 11.6 years [range: 2-32 years] and 271 UC with median follow up 10.4 years [range: 2-36 years]. Data related to the clinical course, EM and laboratory tests were obtained at diagnosis and during follow-up.

RESULTS

EM related with IBD appeared al least once in 46.6% of the patients. Joints manifestations were the most common EM. The EM were equal frequent in UC (51.5%) as in CD (42.2%). Hepatobiliary manifestations (odds ratio [OR] = 1.91; 95% confidence interval [CI] 1.15-3.16; p = 0.007), venous thromboembolism (OR = 4.26; 95% CI, 1.3-15.4; p = 0.006) and arthralgias (OR = 1.59; 95% CI, 1.01-2.5; p = 0.035) were more frequent in UC than CD. Erythema nodosum (OR = 2.35; 95% CI, 1.13-5.0; p = 0.013) and peripheral arthritis (OR = 1.95; 95% CI, 1.02-3.74; p = 0.029) were more frequent in CD. The prevalences of ocular, and the rest of joint manifestations were not different according to UC or CD.

CONCLUSIONS

Prevalence of EM in Spanish IBD patients is among the highest ever reported. The distribution of the EM observed is different between CD and UC. It is necessary to know to allow to prompt diagnosis and prevent undesirable complications.

Genotype-phenotype analysis in childhood-onset Crohn's disease: NOD2/CARD15 variants consistently predict phenotypic characteristics of severe disease

INTRODUCTION

The incidence of early-onset CD in Scotland is among the highest worldwide. Three single nucleotide polymorphisms (SNPs) R702W, G908R and Leu1007finsC in the NOD2/CARD15 gene predispose to adult CD. We investigated the contribution of these variants to disease susceptibility and phenotype in the Scottish early-onset IBD population.

PATIENTS AND METHODS

906 individuals including 247 Scottish IBD patients aged <16 years at diagnosis, 414 parents and 245 controls were genotyped. Transmission disequilibrium testing (TDT), case-control analysis and detailed genotype-phenotype analysis were performed.

RESULTS

The Leu1007finsC variant was associated with susceptibility to CD by case-control (4.2% versus. 1.4%, P = 0.01) and TDT analysis (P = 0.006). The Population Attributable Risk (PAR) for the 3 NOD2/CARD15 mutations was 7.9%. Carriage of NOD2/CARD15 variants was associated with, at diagnosis: decreased albumin (31.0% versus. 9.0%, P = 0.001) and raised CRP (25% versus. 9.5%, P = 0.04) and at follow up: need for surgery (39.5% versus. 12.8%, P = 0.0002) jejunal involvement (50% versus. 18.4%, P = 0.01) jejunal and ileal involvement (50% versus. 10.7%, P = 0.009), raised CRP (57.1% and 12.8%, P = 0.0009), lower weight/height centile (75.0% versus. 20.2%, P = 0.03, 50.0% versus. 16.0%, P = 0.001 respectively) and stricturing disease (45.5% versus. 19.4%, P < 0.05). Multifactorial analysis demonstrated carriage was associated with need for surgery (P = 0.004, OR 4.9 [1.5-14.7]).

CONCLUSIONS

These NOD2/CARD 15 variants in the Scottish early onset CD population have a definite, albeit relatively small contribution to CD susceptibility (PAR 7.9%) but a major impact on phenotype. In particular NOD2/CARD15 variants are strongly associated with several markers of disease severity in pediatric CD, notably need for surgery.

CARD15/NOD2 polymorphisms do not explain concordance of Crohn's disease in Swedish monozygotic twins

BACKGROUND

CARD15/NOD2 polymorphisms are associated with Crohn's disease. There is a high concordance for disease and disease phenotype in monozygotic twin pairs with Crohn's disease.

AIM

We studied CARD15/NOD2 polymorphisms in a Swedish, population-based cohort of monozygotic twins with Crohn's disease to assess whether these variants explain disease concordance.

SUBJECTS AND METHODS

Twenty-nine monozygotic twin pairs (concordant n=9, discordant n=20) with Crohn's disease and 192 healthy controls were investigated for the CARD15/NOD2 variants Arg702Trp, Gly908Arg and Leu1007fsinsC.

RESULTS

CARD15/NOD2 mutations were found in 5/38 (13%) twins with Crohn's disease, corresponding to a total allele frequency of 6.6%. Only 2/9 concordant twin pairs carried any of the variants and the remaining seven were wild type genotype. The total allele frequency was 4.4 times higher (95% confidence interval 1.0-21.5, p=0.06) in concordant twins than in discordant ones, 11.1% versus 2.5%. In healthy controls the total allele frequency was 2.6%.

CONCLUSIONS

CARD15/NOD2 polymorphisms contribute but do not alone explain concordance of Crohn's disease in monozygotic twins and, at least in a Swedish population, other polymorphisms are required. The low occurrence of CARD15/NOD2 mutations in the study and other Northern European populations suggests that these variants are of less importance in Northern Europe.

The relation between NOD2/CARD15 mutations and the prevalence and phenotypic heterogeneity of Crohn's disease: lessons from the Israeli Arab Crohn's disease cohort

The prevalence of Crohn's disease depends on geographic location and racial background. Arg702Trp, Gly908Arg, and Leu1007fsinsC mutations in the NOD2/CARD15 gene are associated with Crohn's disease in Caucasians. The mutation rate among Israeli Jewish patients is 27%-41%. The prevalence of Crohn's disease is much lower in the Israeli Arab compared to the Israeli Jewish population. We studied the NOD2/CARD15 mutation rate and disease phenotype (according to the Vienna classification) among the Israeli Arabs and compared them with those in an Israeli Jewish cohort. We recruited 66 Israeli Arab patients and 122 ethnically matched controls. Five patients (8.2%) and three controls (2.3%) carried one NOD2/CARD15 mutation. The phenotypic characteristics of the Arab and Jewish patients were very similar. We conclude that NOD2/CARD15 mutations do not contribute to Crohn's susceptibility in the Israeli Arab population and suggest that NOD2/CARD15 mutations have an important effect on Crohn's prevalence within a specific population but not on the phenotype.

[TNF-alpha inhibitors in inflammatory bowel disease]

Inflammatory bowel disease (IBD) is a chronic immunoinflammatory response to an stimulus that activates a chain of cellular mediators causing intestinal damage. One of the most well recognized proinflammatory mediators involved in the pathogenesis of IBD is tumor necrosis factor alpha (TNFalpha). The treatment of IBD has advanced in parallel to the improvement of the knowledge of its physiopathology, leading to the development of biological therapies. An example of this kind of treatment is the use of substances that antagonize TNFalpha, such as monoclonal antibodies infliximab, adalimumab, natalizumab, etanercept or onercept, with infliximab being the unique approved for use in IBD. Several studies have demonstrated that inhibition of TNFalpha is useful in the treatment of Crohn's disease (CD). In CD, infliximab induces the remission of relapses which are refractory to the conventional treatment, prevents more relapses and induces a closure of enterocutaneous and perianal fistula that do not respond to first line treatment. However, infliximab is not useful in ulcerative colitis. Infliximab treatment has some drawbacks, such as the development of anti-infliximab antibodies, which cause a loss of efficacy of the treatment and hypersensitivity reactions. Other reported adverse effects of infliximab are the development of autoimmunity, such as that related with antinuclear or anti-DNA antibodies, or the reactivation of infections such as tuberculosis. In fact, a screening for tuberculosis is necessary before administration of infliximab. To reduce the adverse effects due to infliximab immunogenicity, several trials with humanized or completely human agents, such as adalimumab or onercept, are under way. Until the precise stimulus that triggers IBD is identified, biological therapies have a great future and the selective antagonism of TNFalpha is already a reality.

Genotype and phenotype relation in inflammatory bowel disease

Genotype-phenotype analysis helps us to discriminate among various subgroups of IBD and consequently helps us to understand the etiology and pathogenesis as well as develop effective treatments for each subgroup of IBD.

Variants of CARD15 are associated with an aggressive clinical course of Crohn's disease--an IG-IBD study

BACKGROUND

Three major variants of the CARD15 gene confer susceptibility to Crohn's disease (CD). Whether or not these variants correlate with specific clinical features of the disease is under evaluation.

AIM

We investigated the possible association of CARD15 variants with specific clinical characteristics, including the occurrence of anti-Saccharomyces cerevisiae antibodies (ASCA) and antineutrophil cytoplasmic antibodies (ANCA), in a large cohort of inflammatory bowel disease (IBD) patients and their unaffected relatives.

METHODS

Three hundred and sixteen CD patients (156 with positive family history), 408 ulcerative colitis (UC) patients (206 with positive family history), 588 unaffected relatives, and 205 unrelated healthy controls (HC) were studied. Single nucleotide polymorphisms (SNPs) R702W, G908R, and L1007finsC of the CARD15 gene were investigated and correlated to age at diagnosis, gender, family history, localization, extraintestinal manifestations, previous resective surgery, stenosing/fistulizing pattern, ANCA, and ASCA.

RESULTS

Compared to HC, the frequencies of all three variants in CD were significantly increased: 8.7% versus 4.1% for R702W (p < 0.006), 7.3% versus 2.7% for G908R (p < 0.002), 9.3% versus 0.7% for L1007finsC (p < 0.00001). At least one risk allele was found in 38.2% (p < 0.0001, compared to HC), 13.7% (NS), and 15.1% of CD, UC, and HC, respectively. The L1007finsC risk allele was also significantly increased in unaffected relatives of familial (9.5%; p < 0.00001), and sporadic CD (9%; p < 0.00001), compared to HC (0.7%). Sixteen healthy relatives, carriers of two risk alleles, were asymptomatic after 5-8 yr of follow-up. CD carriers of at least one variant were younger (p= 0.03), more likely to have ileal localization (p= 0.0001), stenosing pattern (p= 0.01), previous resective surgery (p= 0.0001), and presence of ASCA (p= 0.0001). No difference in SNPs frequency between familial and sporadic cases of CD was found.

CONCLUSION

In our population, both familial and sporadic CD patients carrying at least one major variant of CARD15 had an aggressive clinical course.

Differential effects of NOD2 variants on Crohn's disease risk and phenotype in diverse populations: a metaanalysis

OBJECTIVES

Three variants of the CARD15/NOD2 gene (SNP8, SNP12, and SNP13) have been associated with Crohn's disease (CD). We assessed the impact of NOD2 variants on the CD risk across diverse populations and examined possible associations with disease phenotype.

METHODS

We performed a metaanalysis searching MEDLINE and EMBASE (last search 05/2004) and contacting field experts.

RESULTS

Forty-two eligible studies contributed data on 206 comparisons. No variants were detected in Asians. In non-Jewish descent Caucasians carriage of SNP8, SNP12, or SNP13 had an odds ratio (OR) for CD of 2.20 (95% CI: 1.84-2.62), 2.99 (95% CI: 2.38-3.74), and 4.09 (95% CI: 3.23-5.18), respectively. For Jewish descent patients the corresponding ORs were 1.74, 1.93, and 2.45, respectively. The OR in carriers of at least two alleles was 17.1 (95% CI: 10.7-27.2). Large studies tended to yield more conservative estimates than smaller studies, so publication or other bias cannot be excluded. Among CD patients, carrying at least one high-risk variant increased slightly the risk for familial disease (OR = 1.49, (95% CI: 1.18-1.87)), modestly the risk of stenosing CD (OR = 1.94, (95% CI: 1.61-2.34)), and more prominently the risk of small bowel involvement (OR = 2.53, (95% CI: 2.01-3.16)).

CONCLUSIONS

SNP8, SNP12, and SNP13 have differential effects on CD risk, with SNP13 having the strongest genetic effect. These NOD2 variants are also significant risk factors for CD phenotype, in particular ileal location.