Analysis of CARD15/NOD2 haplotypes fails to identify common variants associated with rheumatoid arthritis susceptibility

OBJECTIVES: The CARD15/NOD2 gene product plays an important role in host response to bacterial lipopolysaccharides and bacterial muramyl dipeptide via activation of NF-kappaB in monocytes. Mutations in CARD15 are associated with Crohn's disease (CD), a chronic inflammatory bowel disease. In this study we sought to determine whether CD-associated mutations or any common variants of this gene might contribute to susceptibility to another chronic inflammatory disease, rheumatoid arthritis (RA). METHODS: We genotyped 376 Caucasian RA cases and 376 ethnically matched healthy controls for three CD-associated CARD15 mutations. We also genotyped these 752 individuals for 12 common CARD15 single nucleotide polymorphisms (SNPs), determined the linkage disequilibrium structure of the gene, and compared the frequencies of the common CARD15 haplotypes in the RA cases and controls. RESULTS: None of the CD-associated mutations or the CARD15 SNPs was associated with susceptibility to RA. We also found no significant difference in the frequencies of any of the common haplotypes of the CARD15 gene in RA patients and controls. Our haplotype analysis was consistent with earlier observations that all three CD-associated variants independently arose on the same ancestral haplotype. CONCLUSIONS: These data suggest that CARD15 variants are not associated with RA susceptibility.     

Lack of association of the 3′-UTR polymorphism in the NFKBIA gene with Crohn’s disease in an Israeli cohort

BACKGROUND: Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract associated with dysregulation of the immune response. It is caused by a combination of environmental and genetic factors. Patients with CD have a TH1-type inflammatory response characterized by nuclear factor kappa B (NFkappaB) activation. Mutations in the bacterial pattern recognition receptors NOD2/CARD15 and Toll-like receptor 4 (TLR4) genes, which lead to activation of NFkappaB under normal circumstances, have been associated with increased susceptibility for CD. NFkappaB plays a critical role in the immune response and is down-regulated by NFkappaB inhibitor alpha (NFKBIA). NFKBIA was found to be a susceptibility gene for German CD patients lacking NOD2/CARD15 mutations. MATERIALS AND METHODS: A cohort of 231 Israeli CD patients previously genotyped for the single nucleotide polymorphisms (SNPs) in the CARD15, TLR4 susceptibility genes for CD, was analyzed for the 3'-untranslated region (UTR) SNP of the NFKBIA gene in comparison to 100 healthy ethnically matched controls. We evaluated the contribution of the 3'-UTR SNP in NFKBIA in patients with or without other SNPs in CARD15 to age of onset, disease location, and disease behavior (Vienna classification). RESULTS: We did not identify a significant difference in allele and genotype frequencies between either groups or an effect on phenotype. No interactions were found between NFKBIA and any NOD2. CONCLUSIONS: The contribution of population diversity to susceptibility genes for CD plays an important role in disease-associated variants and is important for better understanding of the pathologic mechanisms of the polymorphism.     

The genetics of inflammatory bowel disease

The inflammatory bowel diseases (IBD) comprise complex genetic disorders, with multiple contributing genes. Linkage studies have implicated several genomic regions as likely containing IBD susceptibility genes, with some observed uniquely in Crohn's disease (CD) or ulcerative colitis (UC), and others common to both disorders. The best replicated linkage region, IBD1, on chromosome 16q contains the CD susceptibility gene, NOD2/CARD15. NOD2/CARD15 is expressed in peripheral blood monocytes and is structurally related to the plant R proteins, which mediate host resistance to microbial pathogens. Three major coding region polymorphisms within NOD2/CARD15 have been highly associated with CD among patients of European descent. Having one copy of the risk alleles confers a 2-4-fold risk for developing CD, whereas double-dose carriage increases the risk 20-40-fold. All 3 major CD variants exhibit a deficit in NF-kappaB activation in response to bacterial components. Carriage of NOD2/CARD15 risk alleles is associated with ileal location, earlier disease onset, and stricturing phenotype. Other IBD genomic regions include IBD2 on chromosome 12q (observed more in UC), and IBD3, containing the major histocompatibility complex region. A short genomic region has been associated with CD on chromosome 5q, but the precise contributing gene is as yet unidentified. The characterization of additional IBD susceptibility genes could potentially lead to the identification of novel therapeutic agents for IBD, make possible a molecular reclassification of disease, and increase understanding of the contribution of environmental factors (notably, tobacco and the intestinal microbial milieu) to intestinal inflammation.     

Contribution of CARD15 variants in determining susceptibility to Crohn's disease in Sweden

OBJECTIVE: Crohn's disease (CD) is a chronic inflammatory bowel disorder caused by environmental and genetic factors. Mutations in the CARD15 gene have been associated with CD. No previous case-control CARD15 study has been performed in the Swedish population. MATERIAL AND METHODS: The study comprised of 321 individuals: 178 with CD and 143 healthy controls (HCs), all from Stockholm County. All were genotyped for the three main CD-associated CARD15 variants (R702W, G908R and 1007fs) and phenotypic associations were investigated. RESULTS: The allele frequencies of the R702W variant (4.5% CD versus 0.7% HC, p=0.008, OR = 6.8) and the G908R variant (2.0% CD versus 0% HC, p=0.045) were more common in CD patients than in controls. No significant difference in1007fs variant allele frequency was found between CD patients and controls (2.0% CD versus 1.7% HC, p = 0.8, OR = 1.1). Carriage of CARD15 variants was more common in the CD patients than in controls (15.2% CD versus 4.2% HC, p = 0.001, OR = 4.1, population attributable risk (PAR) = 11.4%). Genotype-phenotype analysis demonstrated that CARD15 variants were associated with ileal disease (p=0.0006, OR = 9.3, CI = 2.2-34) and protective for colonic CD (p = 0.01, OR = 0.18). An association between CARD15 variants and ileal CD (p=0.004, OR = 6.6) was confirmed by multivariate analyses. CONCLUSIONS: The CARD15 variants R702W and G908R, but not 1007fs, are associated with susceptibility to CD in Stockholm County. Genotype-phenotype analysis shows an association with ileal CD. The contribution of these CARD15 mutations in Swedish CD patients overall is low in relation to studies elsewhere in Central Europe and North America, but is consistent with emerging data from elsewhere in Scandinavia and in Northern Europe.     

CARD15 polymorphisms in Behçet's disease

BACKGROUND: Beh?et's disease (BD) is a chronic multi-system inflammatory disorder of unknown aetiology, which shares many features of the inflammatory bowel diseases (IBDs). CARD15 has recently been identified as the first susceptibility gene in Crohn's disease (CD). Objective: Given certain clinical and pathological similarities between CD and BD, and recent evidence of linkage of BD to the CARD15 genomic region, the aim of this study was to investigate the role of CARD15 variants in determining susceptibility to BD. Methods: We studied 374 BD patients from three ethnically homogeneous cohorts (white English, Turkish, and Middle Eastern Arabs of Palestinian and Jordanian descent). Mutation detection of CARD15 was performed by direct sequencing in a subset of patients from each group and the identified variants were genotyped in the complete cohorts. Case-control analyses were carried out with additional stratification by the BD-associated allele, HLA-B*51. Results: Mutation detection identified six previously described CARD15 polymorphisms at a frequency of > 3%. Additionally, two of the three CD-associated polymorphisms were present, but at low frequency. The frequency of haplotypes, constructed from nine genotyped polymorphisms, demonstrated significant variation between different ethnic groups. However, case-control analyses demonstrated no association between the CARD15 polymorphisms and susceptibility to BD, irrespective of HLA-B*51 status. Conclusion: CARD15 variant alleles are not associated with susceptibility to BD. Other shared loci, currently under investigation, may determine susceptibility to both CD and BD.     

Association of chronic non-bacterial osteomyelitis with Crohn’s disease but not with CARD15 gene variants

Chronic non-bacterial osteomyelitis (CNO) is an inflammatory, non-infectious disorder of the skeletal system with unknown etiology. Besides bone-inflammation, patients may present with inflammatory involvement of other tissues. Chronic recurrent multifocal osteomyelitis (CRMO) is the most severe form of CNO. We describe the occurrence of Crohn’s disease (CD) in four patients, previously diagnosed with CRMO. Mutations in CARD15, encoding the NOD2 protein, have recently been found in patients with CD. Based on the occurence of CNO and CD in these four and several reported patients, we hypothesized that CD and CRMO might share a common autoinflammatory process. Thus, we searched for CD associated CARD15 gene variants R702W, G908R and 1007fs in 29 CNO patients, 4 of them additionally diagnosed with CD. In the latter one out of the four showed compound heterozygosity for the gene variants R702W and 1007fs. The allele frequency in the 25 patients diagnosed with CNO but not CD was not different from that already reported in healthy people (R702W 4.0%, G908R 2.0%, 1007fs 2.0%). The occurrence of non-bacterial bone inflammation and granulomatous intestinal inflammation seems to represent an extended phenotype of CD, which partly might be explained by potential disease causing mutations in CARD15. However, CNO without intestinal inflammation is not associated with common CARD15 gene variants. Therefore, other variants of genes coding for proteins involved in innate immunity and inflammation might predispose for the occurrence of CNO.     

CARD15 and HLA DRB1 alleles influence susceptibility and disease localization in Crohn's disease

OBJECTIVES: Crohn's disease (CD) is a chronic inflammatory disease of the gut associated with allelic variants of CARD15 and HLA-DRB1 genes. We investigated the prevalence and effects of these variants in a Canadian CD cohort. METHODS: 507 unrelated CD patients were genotyped for the three major CD-associated variants (Arg702Trp, Gly908Arg, and Leu1007fsinsC) and for thirteen HLA-DRB1 alleles. RESULTS: At least one CARD15 variant was present in 32.5% of the CD patients compared with 20% of controls. The prevalence of CARD15 mutation was similar in both sporadic and familial and Jewish and non-Jewish CD patients. The Gly908Arg variant was significantly higher and the Arg702Trp variant significantly lower in Jewish compared to non-Jewish patients. A positive association between the HLA-DRB1*0103 allele and CD was detected in non-Jewish, familial cases (p = 0.0002), with risk for CD increased by 6.7 fold by the presence of an HLA-DRB1*0103 allele as compared to 1.9 fold and 19 fold by a single or two CARD15 variant alleles, respectively. We show a significant association of ileal involvement with CARD15 variants (OR = 1.8; p = 0.02), HLA-DRB1*0701 (OR = 1.9; p = 0.006) and DRB1*04 (OR = 1.7; p = 0.02) alleles and demonstrate the capacity of combined CARD15 and HLA-DRB1 genotyping to predict ileal disease in CD patients. By contrast, the HLA-DRB1*0103 allele was associated with later age of diagnosis (p = 0.02) and pure colonic disease (p = 0.000013). CONCLUSIONS: These observations confirm the influence of CARD15 and HLA-DRB1 alleles on both CD susceptibility and site of disease and identify genotyping of these variants as a potential tool for improved diagnosis and risk prediction in CD.     

Lessons to be learned from the NOD2 gene in Crohn's disease

The recent discovery that CARD15/NOD2 is involved in the genetic predisposition to Crohn's disease (CD) provides the final demonstration that CD is a genetic disorder. The gene explains about 20% of the genetic susceptibility. CARD15 mutations are present in 30-50% of CD patients compared to 7-20% of healthy controls. Interestingly, CD patients often carry mutations on their two chromosomes suggesting a mutation dose effect. Unfortunately, even if the association between the three main CARD15 mutations (R702W, G908R and 1007fs) and CD is clearly established, it is not useful today to genotype asymptomatic at risk people or inflammatory bowel disease patients as a routine. More interestingly and for the first time, CARD15 points out a specific pathway involved in CD mechanism. Because CARD15 is able to be activated by components of the bacterial wall and further induce the activation of NFkappaB, a proinflammatory molecule, CARD15 discovery makes the link, at the molecular level, between bacteria and inflammation of the digestive tract.     

NOD2/CARD15 does not influence response to infliximab in Crohn's disease

BACKGROUND & AIMS: NOD2/CARD15 was recently identified as the first gene underlying Crohn's disease (CD) susceptibility. Monoclonal antibodies to tumor necrosis factor (TNF)-alpha (infliximab) are a potent treatment for CD, with about 70% of patients responding. It is not clear which factors influence treatment outcome. We assessed whether variants in NOD2/CARD15 are predictive for differences in clinical response. METHODS: Two hundred forty-five CD patients (86 fistulizing, 159 luminal) receiving infliximab in an expanded access program were genotyped for the 3 main associated variants of NOD2/CARD15, without knowledge of the treatment response. Short-term clinical response was assessed at 4 weeks (refractory) or 10 weeks (fistulizing) after first infliximab infusion, and the mean duration of response was calculated. In a subgroup of patients, production of TNF in response to lipopolysaccharide (LPS) in mucosal biopsy tissue was also determined by means of immunoassay, and results were related to the different NOD2/CARD15 genotypes. RESULTS: In total, 32.6% of patients carried mutations in NOD2/CARD15 (18.8% R702W, 8.6% G908R, and 10.2% 1007fs) compared with 15% in controls (P < 0.001). Despite observed differences in TNF production in mucosal biopsy tissue, there was no relationship between the overall presence of a mutation in NOD2/CARD15 or of any of the mutations separately and short-term infliximab response or response duration. Furthermore, multivariate analysis could not identify clinical characteristics that, in combination with NOD2/CARD15 mutations, were associated with response to infliximab. CONCLUSIONS: In this cohort of CD patients, the frequency of NOD2/CARD15 mutations was significantly greater than that of healthy controls. However, NOD2/CARD15 was not predictive of treatment outcome with infliximab in CD.     

Contribution of CARD15 variants in determining susceptibility to Crohn's disease in Sweden

Objective. Crohn's disease (CD) is a chronic inflammatory bowel disorder caused by environmental and genetic factors. Mutations in the CARD15 gene have been associated with CD. No previous case-control CARD15 study has been performed in the Swedish population.

Material and methods. The study comprised of 321 individuals: 178 with CD and 143 healthy controls (HCs), all from Stockholm County. All were genotyped for the three main CD-associated CARD15 variants (R702W, G908R and 1007fs) and phenotypic associations were investigated.

Results. The allele frequencies of the R702W variant (4.5% CD versus 0.7% HC, p=0.008, OR?=?6.8) and the G908R variant (2.0% CD versus 0% HC, p=0.045) were more common in CD patients than in controls. No significant difference in1007fs variant allele frequency was found between CD patients and controls (2.0% CD versus 1.7% HC, p?=?0.8, OR?=?1.1). Carriage of CARD15 variants was more common in the CD patients than in controls (15.2% CD versus 4.2% HC, p?=?0.001, OR?=?4.1, population attributable risk (PAR)?=?11.4%). Genotype–phenotype analysis demonstrated that CARD15 variants were associated with ileal disease (p=0.0006, OR?=?9.3, CI?=?2.2–34) and protective for colonic CD (p?=?0.01, OR?=?0.18). An association between CARD15 variants and ileal CD (p=0.004, OR?=?6.6) was confirmed by multivariate analyses.

Conclusions. The CARD15 variants R702W and G908R, but not 1007fs, are associated with susceptibility to CD in Stockholm County. Genotype–phenotype analysis shows an association with ileal CD. The contribution of these CARD15 mutations in Swedish CD patients overall is low in relation to studies elsewhere in Central Europe and North America, but is consistent with emerging data from elsewhere in Scandinavia and in Northern Europe.     

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.     

NOD2/CARD15 gene variants are linked to failure of antibiotic treatment in perianal fistulating Crohn's disease

OBJECTIVES:  The Crohn's disease (CD) susceptibility gene, nucleotide-binding oligomerizetion domain 2 (NOD2)/caspase recruitment domain 15 (CARD15), is linked to the innate immune response associated with altered epithelial bacterial defense. Its relevance in antibiotic therapy of perianal fistulating CD remains elusive. The aim of the study was to explore systematically the association between NOD2/CARD15 variants and clinical response of perianal fistulas in patients using antibiotic therapy.
METHODS:  Fifty-two patients (median age 36 yr) with draining perianal fistulas were treated with ciprofloxacin (N = 49) or metronidazole (N = 3) for a median duration of 7 wk. Complete response was defined as the absence of any draining fistula despite gentle finger compression. Genotyping for NOD2/CARD15 variants and human beta (β)-defensin 2 (HBD-2) copies was performed by 5' nuclease assays (Applied Biosystems, Foster City, CA). The examiners and laboratory investigators were blinded. The Fisher exact test and Wilcoxon signed rank test were used for statistical analysis.
RESULTS:  Ciprofloxacin was discontinued in one patient due to diarrhea after 2 wk. Complete fistula response was observed in 13 of 39 patients with NOD2/CARD15 wild-type (33.3%) compared with none in patients carrying NOD2/CARD15 variants (0%, P = 0.02). The median number of HBD-2 gene copies between responders and partial/nonresponders was similar.
CONCLUSIONS:  The study result suggests a substantial contribution of NOD2/CARD15 to the antibiotic treatment outcome of perianal fistulating CD. NOD2/CARD15 variants may predispose to an altered intestinal microflora in perianal fistulas that is less responsive to antibiotic treatment.     

Transmission of CARD15 (NOD2) variants within families of patients with inflammatory bowel disease

OBJECTIVES: Three single nucleotide polymorphisms (SNPs) in CARD15 have been independently associated with Crohn's disease (CD). Since nothing is known about the transmission of these variants within families, this was the subject of our study in Flemish patients with inflammatory bowel disease (IBD) and their healthy relatives. METHODS: A cohort of 1,670 individuals (570 CD, 173 UC, 165 healthy controls, 762 first-degree unaffected relatives of CD patients) was genotyped for Arg702Trp, Gly908Arg, and Leu1007fsinsC. Mutant allele and carrier frequencies were compared between groups. Segregation patterns were compared using a bivariate Dale model. RESULTS: The carrier prevalence of CARD15 variants for CD patients was 46.3%, compared to 20.6% for healthy controls and 22.0% for ulcerative colitis (UC) patients (both p < 0.0001). An increased carriage rate of CARD15 variants was observed in unaffected relatives of CD patients (37.3%; p < 0.0001 vs controls), although this was significantly lower than in the CD patients (p = 0.001). Paternal transmission gave a 5.17-fold higher chance for the child to develop the disease compared to maternal transmission (95% CI [1.59, 16.78]; p = 0.0063). UC patients belonging to mixed IBD families carried significantly more mutations (42.3%) compared to other UC patients (18.4%) (p < 0.01). CONCLUSIONS: Maternal transmission of the CARD15 variant allele is associated with a lower proportion of affected individuals compared to paternal transmission. Therefore, maternal transmission does not carry an increased risk of transmission as does paternal transmission. The increased mutation carriage in unaffected siblings of CD patients and in UC patients belonging to mixed families suggests that other factors than CARD15 contribute to the eventual disease expression.     

Tumor necrosis factor receptor gene polymorphisms in Crohn's disease: association with clinical phenotypes

OBJECTIVES: Crohn's disease (CD) is a chronic multifactorial disorder with diverse clinical features that are influenced by a heterogeneous set of genetic factors. TNF-alpha/TNF receptor interactions play a pivotal role in the pathogenesis of the inflammatory response. Our purpose was to determine whether single nucleotide polymorphisms (SNPs) in the TNF receptors confer susceptibility to Crohn's disease and whether they are associated with clinical phenotype. METHODS: A cohort of 205 consecutively identified and unrelated patients with CD and 106 controls were recruited. Subjects were genotyped for polymorphisms in TNFRSF1A (position +36, -609), TNFRSF1B (+196, +1466), along with the three common CARD15 variants and phenotyped for disease behavior. Genotypic and allelic frequencies were compared between CD and controls and a logistic regression model was constructed to determine independent associations with specific clinical phenotypes. RESULTS: Only the TNFRSF1A +36 and TNFRSF1B +196 SNPs were associated with CD (p= 0.0019 and 0.034, respectively). The TNFRSF1A +36 mutation was negatively associated with stricturing disease phenotype (OR = 0.384; CI = 0.166-0.887). In contrast, the TNFRSF1B +196 was negatively associated with colitis (OR = 0.410; CI = 0.191-0.880). These associations were independent of CARD15 mutation status. Finally, TNFRSF1B +196 was negatively associated with surgery in CARD15 negative patients. CONCLUSIONS: These data constitute the first report of an association of TNFRSF1A and TNFRSF1B polymorphisms with CD in a Caucasian population and address the role of TNFR mutations in determining clinical heterogeneity in CD.     

NOD2/CARD15 gene mutation is not associated with susceptibility to Wegener's granulomatosis

OBJECTIVE: Polymorphisms and mutations in the NOD2/CARD15 gene have been reported to increase susceptibility to Crohn's disease (CD) and the rare Blau syndrome, respectively. Both conditions are characterized by granuloma formation. We assessed the influence of variants in the CARD15 gene in another disorder characterized by granuloma, Wegener's granulomatosis (WG). METHODS: Direct DNA sequencing of the CARD15 gene was performed on 25 patients with WG, and an additional 73 patients were genotyped for the 3 CD associated variants, R702W, G908R, and fs1007. RESULTS: In the WG patients, 10 previously reported single nucleotide polymorphisms (SNP) were identified. No SNP were present in the WG patients at significantly different frequencies than the control population. CONCLUSION: Our data provide no evidence to support an association between CARD15 and WG.     

CARD15/NOD2 in a Tunisian Population with Crohn’s Disease

Crohns disease (CD) is a heterogeneous disorder. A genetic linkage to chromosome 16 (IBD1) has been previously observed and replicated in unrelated populations. Recently, in this region, NOD2/CARD15 has been identified as a susceptibility gene. The aim of this report is to determine whether this gene is implicated in CD in a Tunisian population. One hundred thirty patients with CD and 90 healthy individuals were genotyped for the three common NOD2 variants (C2104T in exon 4, G2722C in exon 8, and 3020insC in exon 11). Furthermore, the 11 exons of the NOD2 gene were sequenced in 20 patients with CD. Results showed that the frequency of the CARD15 variants in the Tunisian population is significantly lower than that observed in the European and American population. Direct sequencing of CARD15 did not permit us to identify a characteristic mutation in our population. No association was confirmed between CD and the NOD2 gene in our Tunisian population. Furthermore, the NOD2/CARD15 gene has a variable association with CD in different populations. These results indicate the genetic variation of CD in different ethnic groups.     

CARD15/NOD2 gene variants are associated with familially occurring and complicated forms of Crohn's disease

BACKGROUND: Variants of the caspase activating recruitment domain 15/nucleotide oligomerisation domain 2 (CARD15/NOD2) gene have been associated with susceptibility to Crohn's disease (CD). Aim: Our aim was to evaluate the allele frequencies of the CARD15 variants R702W, G908R, and 1007fs in Finnish inflammatory bowel disease (IBD) patients and to search for possible associations between CARD15 variants and occurrence of familial forms of IBD or complicated forms of CD. PATIENTS AND METHODS: We investigated 198 sporadic CD patients, 46 probands with familial CD, 27 CD probands from mixed IBD families, 99 unrelated patients with ulcerative colitis (UC), and 300 control individuals for the occurrence of the CARD15 gene variants R702W, G908R, and 1007fs. RESULTS: In CD patients, the allele frequencies for the rare variants of these polymorphisms were 3.3%, 0.6%, and 4.8% (total 8.7%), and the corresponding frequencies in healthy controls were 1.8%, 0%, and 1.7% (total 3.5%) (8.7% v 3.5%; p<0.01). In UC patients allele frequencies were comparable with those in controls. The frequency of the 1007fs polymorphism variant allele was significantly higher among all CD patients than in controls (4.8% v 1.7%; p<0.01) but there was no significant difference in allele frequencies between the CD and UC groups. The 1007fs allele frequency was higher in familial CD than in non-familial cases with CD (10.9% v 3.5%; p<0.01). There were no significant differences in the allele frequencies of the R702W and G908R polymorphisms between CD patients, UC patients, and controls. We found that 15.5% of CD patients, 9.1% of UC patients, and 6.7% of controls carried at least one of the CARD15 variants. In CD patients carrying at least one of the three NOD2 variants, the ileum was affected more often than in non-carrier CD patients (90% v 73%; p<0.05), they had stricturing or penetrating disease more often than non-carriers (88% v 56%; p<0.01), and they had an increased need for bowel surgery. CONCLUSIONS: The frequency of NOD2 gene variants was lower in genetically homogenous Finns than in other populations. The 1007fs variant was associated with CD. The occurrence of CARD15 variants predicted ileal location as well as stricturing and penetrating forms of CD.     

NOD2/CARD15 disease associations other than Crohn's disease

At this moment, few confirmed associations between NOD2 mutations and diseases other than Crohn's disease (CD) and Blau syndrome (BS) have been reported, but research is ongoing in several fields where a genetic susceptibility factor and/or a role for the innate immune system is suspected. Whether the Crohn's-associated CARD15 mutations lead to a loss or gain of function of the NOD2 receptor is subject to controversy, and by which mechanisms this change in function might increase the susceptibility to CD is still under investigation. The possible involvement of NOD2/CARD15 in the pathogenesis of certain diseases with already (partially) unraveled pathophysiologic mechanisms might contribute to our further understanding of NOD2/CARD15 and its function in CD. We review studies on the association of CARD15 variants with diseases other than CD. The association of NOD2/CARD15 mutations with CD and BS, and possibly also early onset sarcoidosis, suggests a role for the gene in the development of granulomata and granulomatous diseases, possibly by inappropriate activation of the immune system. The data from the oncology field suggest that this inappropriate activation might even lead to uncontrolled proliferation of certain cell types. The studies in allergic diseases and atopy are the largest so far, and the association of NOD2/CARDI5 mutations with atopic phenotypes might be an indication that CARD15 also plays a role in the Th2 pathway. Finally, transplantation studies indicate that the genetic background of a patient should be taken into account when considering hematopoietic stem cell transplantation, given the increased risk of mortality and graft versus host disease observed. Whether NOD2 variants are also associated with an increased risk for infections and sepsis in patients receiving immunosuppressive therapies is unclear.     

Role of CARD15, DLG5 and OCTN genes polymorphisms in children with inflammatory bowel diseases

AIM: To investigate the contribution of variants of CARD15, OCTN1/2 and DLG5 genes in disease predispo- sition and phenotypes in a large Italian cohort of pediatric patients with inflammatory bowel diseases (IBD). METHODS: Two hundred patients with Crohn’s disease (CD), 186 ulcerative colitis (UC) patients, 434 par- ents (217 trios), and 347 healthy controls (HC) were studied. Polymorphisms of the three major variants of CARD15, 1672C/T and -207G/C SNPs for OCTN genes, IGR2096a_1 and IGR2198a_1 SNPs for the IBD5 locus, and 113G/A variant of the DLG5 gene were evaluated. Potential correlations with clinical sub-phenotypes were investigated. RESULTS: Polymorphisms of CARD15 were significantly associated with CD, and at least one variant was found in 38% of patients (15% in HC, OR = 2.7, P < 0.001). Homozygosis for both OCTN1/2 variants was more com- mon in CD patients (1672TT 24%, -207CC 29%) than in HC (16% and 21%, respectively; P = 0.03), with an in- creased frequency of the TC haplotype (44.8% vs 38.3% in HC, P = 0.04). No association with the DLG5 variant was found. CD carriers of OCTN1/2 and DLG5 variants more frequently had penetrating disease (P = 0.04 and P = 0.01), while carriers of CARD15 more frequently had ileal localization (P = 0.03). No gene-gene interaction was found. In UC patients, the TC haplotype was morefrequent (45.4%, P = 0.03), but no genotype/phenotype correlation was observed. CONCLUSION: Polymorphisms of CARD15 and OCTN genes, but not DLG5 are associated with pediatric on- set of CD. Polymorphisms of CARD15, OCTN, and DLG5 genes exert a weak influence on CD phenotype.