NOD2/CARD15 mutation analysis and genotype-phenotype correlation in Jewish pediatric patients compared with adults with Crohn's disease

Clinical and Phenotypic Differences in Inflammatory Bowel Disease Among Arab and Jewish Children in Israel

BACKGROUND

Data on inflammatory bowel disease (IBD) phenotypes among the Arab population in Israel or in the neighboring Arab countries is scarce.

AIM

We aimed to assess differences in disease phenotype among Arab and Jewish children living in Israel.

METHODS

We performed a retrospective chart review of pediatric IBD cases, which were diagnosed at the Schneider Children's Medical Center and Ha'Emek Medical Center in Israel between 2000 and 2014. Demographic, clinical, and phenotypic variables were compared between Arabs and Jews from Eastern (Sephardic) and Western (Ashkenazi) origin.

RESULTS

Seventy-one Arab children with IBD were compared with 165 Ashkenazi and 158 Sephardic Jewish children. Age and gender did not differ between groups. Sephardic and Ashkenazi Jewish Crohn's disease (CD) patients had significantly more stenotic behavior (24 and 26 vs. 5%, p = 0.03) and less fistulzing perianal disease (15 and 11 vs. 31%, p = 0.014) compared with Arab patients. Arab children with ulcerative colitis (UC) had more severe disease at diagnosis compared to Sephardic and Ashkenazi Jews reflected by higher Pediatric UC Activity Index (45 vs. 35 and 35, respectively, p = 0.03). Arab patients had significantly lower proportion of anti-Saccharomyces cerevisiae antibodies positivity (in CD) and perinuclear anti-neutrophil cytoplasmic antibodies positivity (in UC) than both Sephardic and Ashkenazi Jewish children (23 vs. 53 and 65%, p = 0.002 and 35 vs. 60 and 75%, respectively, p = 0.002).

CONCLUSION

Arab and Jewish children with IBD differ in disease characteristics and severity. Whether genetic or environmental factors are the cause for these differences is yet to be determined.

Autophagy genes variants and paediatric Crohn's disease phenotype: a single-centre experience

BACKGROUND AND AIMS

Little evidence demonstrating the correlation between several single nucleotide polymorphisms and a specific phenotype of Crohn's disease has been reported in children. We investigated the relationship between autophagy genes variants and clinical features in our children with Crohn's disease.

METHODS

Genotyping for ATG16L1, NOD2/CARD15, and IRGM1 was performed in 80 consecutive patients with Crohn's disease (median age: 11 years; range: 0.7-17.9 years). Crohn's disease location and behaviour were classified using the Paris classification. Additional data were collected from clinical records on patients' demographics, age at symptom onset and diagnosis, extraintestinal manifestations, therapy, clinical relapses, and need of surgical intervention.

RESULTS

Patients homozygous for the risk allele ATG16L1 (T300A) showed a trend towards switching to a stricturing phenotype during the course of disease compared to children either homozygous for the wild-type allele or heterozygous for the ATG16L1 single nucleotide polymorphism (p=0.01). Homozygosity for the ATG16L1 risk allele was associated with a major recurrence of clinical relapses and earlier introduction of immunosuppressants (p=0.006 and p=0.04, respectively). Heterozygosity for the NOD2 rs2066847 allele was associated with major ileal involvement (p=0.01).

CONCLUSION

In patients carrying the T300A variant, Crohn's disease follows a more aggressive clinical course.

IBD across the age spectrum: is it the same disease?

IBD is a chronic disorder with disease onset ranging from early childhood to beyond the sixth decade of life. The factors that determine the age of onset currently remain unexplained. Is timing of occurrence a random event or is it indicative of different pathophysiological pathways leading to different phenotypes across the age spectrum? Over the past decade, several studies have suggested that the characteristics and natural history of IBD seem to be different according to age of onset. This heterogeneity suggests that the respective contributions of genetics, host immune system and environment to the aetiology and phenotype of Crohn's disease and ulcerative colitis are different across ages. Critical reviews that focus on differences characterizing IBD between age groups are scarce. Therefore, this Review updates the knowledge of the differences in epidemiology, clinical characteristics, and natural history of paediatric, adult and elderly-onset IBD. In addition, potential differences in host-gene-microbial interactions according to age are highlighted.

Small bowel diagnostics: current place of small bowel endoscopy

The small intestine has been difficult to examine by traditional endoscopic and radiologic techniques. Until the end of the last century, the small bowel follow through was the primary diagnostic tool for suspected small bowel disease. In recent years capsule endoscopy, deep enteroscopy using balloon-assisted or spiral techniques, computerized tomography and magnetic resonance enteroclysis or enterography have facilitated the diagnosis, monitoring, and management of patients with small bowel diseases. These technologies are complementary, each with its advantages and limitations. In the present article, we will discuss the different options and indications for modern diagnostic methods for visualization of the small bowel. We also try to provide a clinical rationale for the use of these different diagnostic options in less established, newly emerging, indications for small bowel evaluation.

MR enterography versus capsule endoscopy in paediatric patients with suspected Crohn's disease

OBJECTIVE

The aim of this prospective study was to compare the diagnostic yield of MR enterography (MRE) with small-bowel capsule endoscopy (SBCE) in paediatric patients with suspected Crohn's disease (CD).

METHODS

Paediatric patients with suspected CD were considered eligible to be enrolled in the study. All patients underwent diagnostic work-up including 1.5-T MRE, ileo-colonoscopy and oesophagogastroduodenoscopy. SBCE was not performed if MRE showed SB stricture or extra-intestinal findings consistent with symptoms.

RESULTS

Sixty consecutive paediatric patients (36 male; average age 14) were enrolled into the study. A positive diagnosis for CD was made in 19 patients, 29 had a negative result and 12 were affected by other gastro-intestinal conditions. SBCE was performed in 37 patients (61.7%); 23 patients were excluded (strictures in five, extra-intestinal findings in 11 and parents' refusal in seven cases). The accuracy, sensitivity, and specificity of MRE and SBCE were 98.3%, 100%, 97.6%, and 91.9%, 90.9%, 92.3%, respectively.

CONCLUSION

Both MRE and SBCE are accurate methods for patients with suspected CD. MRE can be used as a primary imaging technique in suspected CD, in that it allows access to the ileal stricture, which forms a contra-indication for SBCE and provides extra-intestinal information.

Response to medical treatment in patients with Crohn's disease: the role of NOD2/CRAD15, disease phenotype, and age of diagnosis

PURPOSE

Factors influencing response to medications in Crohn's disease (CD) patients are not fully understood. We aimed to evaluate the relationships between NOD2/CARD15 mutations, disease phenotype and age of CD diagnosis and response to medical treatment with systemic steroids, azathioprine (AZA) or 6-mercaptopurine (6-MP), and infliximab.

METHODS

A retrospective medical records analysis was made of patients previously tested for the CD-associated NOD2/CARD15 mutations. Harvey- Bradshaw score was used to assess remission or response to therapy.

RESULTS

CD-associated NOD2/CARD15 mutations were not related to the rate of steroids dependency or clinical response to AZA/6-MP and infliximab. Steroid dependency was associated with colonic involvement. Thirty-three of 127 (26%) patients with colonic disease were steroid dependent, compared with 7/72 (9.7%) patients with isolated small bowel disease (ISBD), (p = 0.009). ISBD was mildly associated with a better remission/response to AZA/6-MP treatment. Disease behavior and age of diagnosis were not related to response to therapy.

CONCLUSIONS

Response to treatment with systemic steroids, AZA/6-MP and infliximab are not related to NOD2/CARD15 mutations, age of diagnosis and disease behavior. Patients with colonic disease have higher rates of steroid dependency.

Inflammatory bowel disease in the Asia-Pacific area: a comparison with developed countries and regional differences

The Asia-Pacific region has been marked as an area with a low incidence of inflammatory bowel disease (IBD), although confusion always existed as to whether this low incidence was a result of low diagnostic awareness, a high incidence of infective diarrhoea and its diagnostic overlap or a true low incidence. As epidemiological studies from this region are being made available it is clear that the incidence and prevalence rates of IBD in Asia-Pacific region are low compared with Europe and North America. They are however, increasing rapidly. There are substantial variations in the incidence and prevalence rates of IBD in various ethnic groups in Asia. The highest incidence rates are recorded from India, Japan and the Middle East and there exists a genetic predisposition of South Asians (Indians, Pakistanis and Bangladeshis) to ulcerative colitis (UC). It appears that certain racial groups are more prone than others to develop IBD. For instance, Indians in South-East Asia have higher rates than Chinese and Malays. While there is a host genetic predisposition, environmental factor(s) may be responsible for this difference. The clinical phenotypes and complication rates of Asian IBD resemble those of the Caucasian population in general, but some heterogeneity is observed in different regions of Asia. There is no evidence of a north-south or an east-west divide in the Asia-Pacific region. The available studies suggest an increasing incidence of UC in the Asia-Pacific region and hence it is an appropriate time to launch well-designed epidemiological studies so that etiopathogenetic factors can be identified. There is a male predominance in Crohn's disease in the Asian population. The NOD2/CARD15 gene is not associated with CD in the Japanese, Korean, Chinese and Indian population.

NOD2/CARD15, ATG16L1 and IL23R gene polymorphisms and childhood-onset of Crohn’s disease

AIM: To assess whether the polymorphisms of NOD2/CARD15, autophagy-related 16-like 1 (ATG16L1), and interleukin-23 receptor (IL23R) genes play a more critical role in the susceptibility of childhood-onset than in adult-onset Crohn’s disease (CD).

METHODS: Polymorphisms R702W, G908R, and 3020insC of NOD2/CARD15; rs2241880 A/G of ATG16L1, and rs11209026 (R381Q) of IL23R gene were assessed in 110 childhood-onset CD, 364 adult-onset CD, and 539 healthy individuals. Analysis of polymorphisms R702W, G908R, and 3020insC of NOD2/CARD15 genotyping was performed by allele specific polymerase chain reaction (PCR) or by PCR-restriction fragment length polymorphism analysis. The polymorphisms rs2241880 A/G of the ATG16L1, and rs11209026 (R381Q) of the IL23R gene in the children’s cohort were genotyped by PCR and melting curve analysis whereas adult group genotyping was performed using the Affymetrix Genome-Wide Human SNP Array 5.0 (500K).

RESULTS: The 3020insC allele in NOD2/CARD15 was significantly higher in childhood than in adult-onset CD (P = 0.0067). Association with at least 1 NOD2/CARD15 variant was specific for ileal disease (with or without colonic involvement). Even if the frequency of G allele of the rs2241880 ATG16L1 polymorphism was increased in both paediatric and adult CD patients compared to controls (P = 0.017 and P = 0.001, respectively), no difference was observed between the childhood and the adult cohort. The rare Q allele of IL23R rs11209026 polymorphism was underrepresented in both paediatric and adult CD cases (P = 0.0018 and P = 0.04, respectively) and no difference was observed between the childhood and the adult cohort. The presence of the rs2241880 ATG16L1 and rs11209026 IL23R polymorphisms did not influence disease phenotype.

CONCLUSION: Polymorphism 3020insC in NOD2/CARD15 occurs statistically significantly more often in patients with childhood-onset CD than in patients with adult-onset CD. The ATG16L1 and IL23R variants are associated with susceptibility to CD, but not early-onset disease.

Evolving paradigms in the pathogenesis of IBD

The pathogenesis of all immune-mediated inflammatory diseases has been carefully studied over the past several decades, but it is only recently that we have come to appreciate common pathways and genes. This is especially true for the inflammatory bowel diseases (IBD) Crohn's disease and ulcerative colitis, where a keener appreciation of the contributions of genetics, environment, and immune response have been dissected. In fact, in many ways, IBD has become the model for studying such disorders. The complex nature of interactions is continuing to be defined, and novel therapies targeting defects in these interactions have been developed and are being tested in the clinic. The era of bench to bedside has finally matured, and cures for debilitating diseases are now in sight. This review describes our current state of knowledge of each component of IBD pathogenesis. What has evolved is a clearer picture and novel targets for therapy.

Polymorphisms in the IBD5 locus are associated with Crohn disease in pediatric Ashkenazi Jewish patients

OBJECTIVES

To analyze the IBD5 locus in a homogenous cohort of Ashkenazi Jewish (AJ) children with Crohn disease (CD).

PATIENTS AND METHODS

A total of 83 AJ children with CD and 73 AJ healthy controls were studied. Genotyping for single nucleotide polymorphisms (SNPs) including OCTN1 (SLC22A4; 1672C-->T), OCTN2 (SLC22A5; 207G-->C), IGR2096, IGR2198, and IGR2230 genes was performed using the TaqMan system. NOD2/CARD15 variants also were typed using established methods.

RESULTS

All IBD5 SNPs tested were in linkage disequilibrium (D'>0.8), and showed significant association with CD in our cohort of AJ children. The IGR2096 SNP, which is not located within the same linkage disequilibrium block as the OCTN1 and 2 SNPs, showed an even stronger association with CD (P = 0.017; odds ratio = 1.7). Patients with CD who had the OCTN1 susceptibility allele were more likely to carry 1 of the 3 NOD2/CARD15 SNPs tested (P = 0.01; odds ratio = 4.8).

CONCLUSIONS

We have demonstrated a significant association between the IBD5 locus and CD in a homogenous cohort of pediatric AJ patients. Due to the tight linkage disequilibrium in the region, it is not possible to identify the causative IBD5 variant. Future functional studies will ultimately reveal the causative gene variant at this locus.

Identification of NOD2/CARD15 mutations in Malaysian patients with Crohn's disease

OBJECTIVE

The NOD2/CARD15 gene has been identified as an important susceptibility gene for Crohn's disease (CD) but the three common disease predisposing mutations (DPM) found in developed countries have not been identified in Asian populations. The aim of our study was to look for the DPM in our multiracial population and to discover whether there were any differences in the three major ethnic groups; Malay, Chinese and Indian.

METHODS

Blood samples from consecutive CD patients and healthy controls were obtained and analyzed for the three common mutations (R702W, G908R, 1007fs) but in addition to this, we also looked for the SNP5 and JW1 variants which are associated with CD in Ashkenazi Jews. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to identify the mutations, which was confirmed by sequencing. The baseline socio-demography and clinical characteristics of the CD patients were recorded.

RESULTS

Overall 45 patients (three Malays, 15 Chinese, 26 Indians and one other) with confirmed CD and 300 controls were recruited. The three common DPM were not observed in either the CD patients or the controls. Neither the SNP5 nor the JW1 mutation was found in any of the controls. However, the SNP5 mutation was identified in six (13.3%) Indian CD patients and the JW1 mutation in eight CD patients who are different from those carrying the SNP5 mutation: one Malay (33.3%), two Chinese (13.3%), one other (Portuguese) and four Indians (15.4%). The presence of SNP5 was strongly associated with CD in the Indian population and that of JW1 was strongly associated with CD overall and in each of the major ethnic groups. There was a trend towards a younger age of onset and stricturing disease in patients carrying the JW1 mutation.

CONCLUSION

These findings suggest the presence of novel DPM in the NOD2/CARD15 gene in Asian patients with CD.

[Susceptibility genetic variants in Hungarian morbus Crohn and ulcerative colitis patients]

We examined several susceptibility genetic variants to inflammatory bowel disease (Crohn's disease, ulcerative colitis) in Hungarian population, such as the CARD15 R702W, G908R, 1007finsC genetic variants, the SLC22A4 C1672T and SLC22A5 G-207C variants and their determined TC haplotype, the CTLA4 gene A+49G genetic variant and the rs10889677 C/A, rs2201841 T/C, rs1884444 G/T variants of the IL23R gene. We examined 201 adult patients with Crohn's disease, 241 adult patients with ulcerative colitis and 19 pediatric patients with Crohn's disease. For control 235 adult and 49 pediatric subjects were used. The genotyping was carried out using PCR/RFLP methods and direct sequencing. From the CARD15 gene mutations in the adult Crohn's disease population the 1007finsC, while in the pediatric population the 1007finsC and the G908R were significantly associated with an increased risk for Crohn's disease. We found no significant differences comparing the results of the patients and the controls by the SLC22A4, SLC22A5 genetic variants and the TC haplotype. The A+49G variant of the CTLA4 gene was not an independent determinant to inflammatory bowel disease. We found that the IL23R gene variants, rs10889677 C/A and rs2201841 T/C appear to increase susceptibility to Crohn's disease. It depends on the different populations whether this genetic variant means an obligatory risk factor to inflammatory bowel disease.

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.

1007fs, G908R, R702W mutations and P268S, IVS8+158 polymorphisms of the CARD15 gene in Turkish inflammatory bowel disease patients and their relationship with disease-related surgery

INTRODUCTION

CARD15 gene mutations may present different frequencies in populations and sometimes surgical interventions may become a necessary therapy for inflammatory bowel disease patients. Mutations of 1007fs, G908R, R702W and polymorphisms of P268S, IVS8+158 of the CARD15 gene and their relation with disease-related surgery were investigated in Turkish inflammatory bowel disease patients in this study.

MATERIAL AND METHOD

1007fs, G908R, R702W mutations and P268S, IVS8+158 polymorphisms of CARD15 gene were analyzed in 130 inflammatory bowel disease patients (67 Crohn's disease, 63 ulcerative colitis) and 87 healthy controls. After obtaining DNA samples, genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Results were evaluated by statistical analysis and accepted as significant if P < 0.05.

RESULTS

R702W gene mutation was significantly lower in the inflammatory bowel disease group (1.5%) than the controls (4.8%) (P < 0.05). The overall allele frequency of mutations in the inflammatory bowel disease group (2.7%) was lower than in controls (6.6%) (P < 0.05). Disease-related surgery history was present in 20 Crohn's and 25 ulcerative colitis patients; familial history was present in four Crohn's and five ulcerative colitis patients. Statistically, no relationship was detected between disease-related surgeries and the investigated genetic tests.

CONCLUSION

In Turkish patients, no important relationship was detected between the investigated allele frequencies of the CARD15 gene and inflammatory bowel disease nor between disease-related surgeries and inflammatory bowel disease.

Special issues in pediatric inflammatory bowel disease

The incidence of pediatric inflammatory bowel disease (IBD) is rising and recent advances in diagnostics and therapeutics have improved the care provided to these children. There are distinguishing features worth noting between early onset and adult onset IBD. Physical and psychosocial development remains a critical target for the comprehensive management of pediatric IBD. Children are not just little adults and consideration must be given to the stages of development and how these stages impact disease presentation and management. The final stage will be the transition from pediatric care to that of adult oriented care and special consideration must be given to make this a successful process. This review highlights special considerations in the management of the child with IBD.

Epidemiology, genes and inflammatory bowel diseases in childhood

There is evidence that inflammatory bowel disease is immunologically mediated and that genetic factors play an important aetiological role. The identification of disease susceptibility genes has led to significant progress in our understanding of the pathogenesis of Crohn's disease. Genes linked to Crohn's disease play critical roles in the normal function of the innate immune system, and genes linked to epithelial integrity may play a role in the pathogenesis of inflammatory bowel disease as well. However, the dynamic epidemiology of both Crohn's disease and ulcerative colitis suggests that extrinsic environmental factors acting at the population level may be involved in their pathogenesis. These environmental factors may be responsible for the rising incidence of inflammatory bowel disease.

Pediatric onset Crohn's colitis is characterized by genotype-dependent age-related susceptibility

BACKGROUND

Pediatric onset Crohn's disease (CD) is associated with more colitis and less ileitis compared with adult onset CD. Differences in disease site by age may suggest a different genotype, or different host responses such as decreased ileal susceptibility or increased susceptibility of the colon.

METHODS

We evaluated 721 pediatric onset CD patients from 3 cohorts with a high allele frequency of NOD2/CARD15 mutations. Children with isolated upper intestinal disease were excluded. The remaining 678 patients were evaluated for interactions between age of onset, NOD2/CARD15, and disease location.

RESULTS

We found an age-related tendency for isolated colitis. Among pediatric onset patients without NOD2/CARD15 mutations, colitis without ileal involvement was significantly more common in first-decade onset patients (P = 4.57 x 10(-5), odds ratio [OR] 2.76, 95% confidence interval [CI] 1.72-4.43). This was not true for colonic disease with ileal involvement (P = 0.35), or for isolated colitis in patients with NOD2/CARD15 mutations (P = 0.61). Analysis of 229 patients with ileal or ileocolonic disease and a NOD2/CARD15 mutation disclosed that ileocolitis was more prevalent through age 10, while isolated ileitis was more prevalent above age 10 (P = 0.016). NOD2/CARD15 mutations were not associated with age of onset.

CONCLUSIONS

In early-onset pediatric CD, children with NOD2/CARD15 mutations demonstrate more ileocolitis and less isolated ileitis. Young children without NOD2/CARD15 mutations have an isolated colonic disease distribution, suggesting that this phenotype is associated with genes that lead to a specific phenotype of early-onset disease.

Genetic susceptibility has a more important role in pediatric-onset Crohn's disease than in adult-onset Crohn's disease

BACKGROUND

Genetic susceptibility may play a more important role in the etiology of early-onset inflammatory bowel disease (IBD) than in late-onset IBD, and therefore pediatric-onset IBD patients can be expected to have a higher frequency of gene mutations. We aimed to determine genotypes and phenotypes of patients with pediatric-onset IBD, to compare them with those of patients with adult-onset IBD and with controls, and to identify genotype-phenotype associations.

METHODS

Polymorphisms R702W, G908R, and 3020insC of CARD15 (caspase activating recruitment domain 15); Asp299Gly and Thr399Ile of TLR4; -207G-->C, 1672C-->T (L503F), rs3792876, rs274551, rs272893, and rs273900 of SLC22A4/5; and 113G-->A as well as rs2289311, rs1270912, and rs2165047 of DLG5 (Drosophila discs large homologue 5) were assessed in 103 pediatric-onset and 696 adult-onset IBD patients. Phenotypic classification was based on disease localization and behavior.

RESULTS

Homozygosity for 3020insC in CARD15 was significantly higher in patients with pediatric-onset Crohn's disease (CD) than in patients with adult-onset CD (4.2% versus 0.6%, 95% confidence interval [CI] 1.2-42.0). Homozygosity for single-nucleotide polymorphism (SNP) rs3792876 in SLC22A4/5 was significantly higher in patients with pediatric-onset CD than in patients with adult-onset CD (6.1% versus 1.1%, P=0.02). Polymorphism 3020insC in CARD15 was associated with ileal involvement (1.9% versus 13.3%, CI 1.0-53.8) and a positive family history (6.1% versus 20%, CI 1.2-9.0). DLG5 SNP rs2165047 was significantly associated with perianal disease (50% versus 21.2%, CI 1.4-4).

CONCLUSIONS

Polymorphisms 3020insC in CARD15 and SNP rs3792876 in SLC22A4/5 occurred statistically significantly more often in patients with pediatric-onset CD than in patients with adult-onset CD. Polymorphisms 3020insC in CARD15 and SNP rs2165047 in DLG5 were associated with specific phenotypes in this pediatric-onset CD cohort.

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 predisposition 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 parents (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 common in CD patients (1672TT 24%, -207CC 29%) than in HC (16% and 21%, respectively; P = 0.03), with an increased 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 more frequent (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 onset of CD. Polymorphisms of CARD15, OCTN, and DLG5 genes exert a weak influence on CD phenotype.

Polymorphisms of tumor necrosis factor-alpha but not MDR1 influence response to medical therapy in pediatric-onset inflammatory bowel disease

AIM

We investigated the contribution of variants of tumour necrosis factor (TNF)-alpha and MDR1 genes in the predisposition and response to medical therapy in a large pediatric cohort of patients with Crohn disease (CD) and ulcerative colitis (UC).

PATIENTS AND METHODS

In this study, 200 patients with CD, 186 patients with UC, 434 parents (217 trios), and 347 healthy unrelated controls were investigated. Single-nucleotide polymorphisms -G308A and -C857T of the TNF-alpha gene and C3435T of the MDR1 gene were investigated and correlated with clinical subphenotypes and efficacy of medical therapy.

RESULTS

The frequency of the -308A allele of the TNF-alpha gene was significantly increased in both patients with CD (15%; odds ratio [OR] = 2.79; P < 0.01) and patients with UC (11%; OR = 1.96; P < 0.003) compared with controls (6%). Carriers of this allele were 27% in CD (OR = 2.94; P < 0.01) and 19% in UC (OR = 1.86; P = 0.015) compared with 11% in healthy controls. No significant difference was found for both the -C857T and C3435T single-nucleotide polymorphisms. With the genotype/phenotype analysis, no correlation in patients with UC with the MDR1 gene was found. CD carriers of the -308A allele had a higher frequency of surgical resection (35% vs 20%; OR = 2.1; P = 0.035) and more frequent resistance to steroids (22% vs 8%; OR = 0.29; P = 0.032) compared with noncarriers. These findings were confirmed by stepwise logistic regression.

CONCLUSIONS

In our pediatric cohort, the promoter -308A polymorphism of TNF-alpha but not the MDR1 gene is significantly involved in the predisposition to both CD and UC. This polymorphism carries a significant reduction in response to steroid therapy, probably leading to a more frequent need for surgical resection.

Prevalence of SLC22A4, SLC22A5 and CARD15 gene mutations in Hungarian pediatric patients with Crohn’s disease

AIM: To investigate the frequency of the common NOD2/CARD15 susceptibility variants and two functional polymorphisms of OCTN cation transporter genes in Hungarian pediatric patients with Crohn’s disease (CD).

METHODS: A cohort of 19 unrelated pediatric and 55 unrelated adult patients with Crohn’s disease and 49 healthy controls were studied. Genotyping of the three common CD-associated CARD15 variants (Arg702Trp, Gly908Arg and 1007finsC changes) with the SLC22A4 1672C→T, and SLC22A5 -207G→C mutations was performed by direct sequencing of the specific regions of these genes.

RESULTS: At least one CARD15 mutation was present in 52.6% of the children and in 34.5% of the adults compared to 14.3% in controls. Surprisingly, strongly different mutation profile was detected in the pediatric versus adult patients. While the G908R and 1007finsC variants were 18.4% and 21.1% in the pediatric group, they were 1.82% and 11.8% in the adults, and were 1.02% and 3.06% in the controls, respectively. The R702W allele was increased approximately two-fold in the adult subjects, while in the pediatric group it was only approximately 64% of the controls (9.09% in the adults, 2.63% in pediatric patients, and 4.08% in the controls). No accumulation of the OCTN variants was observed in any patient group versus the controls.

CONCLUSION: The frequency of the NOD2/CARD15 susceptibility variants in the Hungarian pediatric CD population is high and the profile differs from the adult CD patients, whereas the results for SLC22A4 and SLC22A5 mutation screening do not confirm the assumption that the carriage of these genotypes means an obligatory susceptibility to CD.

Ileal lymphonodular hyperplasia is not associated with NOD2/CARD15 mutations

INTRODUCTION

Lymphonodular hyperplasia (LNH) is a mass of lymphoid tissue that has been described in the terminal ileum, colon and duodenum mainly in children. Controversy exists regarding the benign nature of LNH. The combination of chronic abdominal pain and hematochezia leads many of these patients to undergo investigations for inflammatory bowel diseases. NOD2/CARD15 on chromosome 16 has been identified as a susceptibility gene for Crohn disease (CD). No study has yet examined the possible association of NOD2/CARD15 mutations with patients with LNH. The purpose of this study was to investigate the presence of NOD2/CARD15 mutations in patients with clinically proven LNH.

METHODS

Children and young adults with gastrointestinal symptoms diagnosed as having terminal ileum LNH were eligible for the study.

RESULTS

The study group consisted of 32 patients (15 males and 17 females), age range 3-23 years, mean 13.1 +/- 5 years. Twenty-seven (84%) had abdominal pain, 3 (9%) had rectal bleeding. The duration of symptoms ranged from 1-60 months (17.9 +/- 14.5). Only 2 patients (6.2%) were found to be heterozygote for the NOD2/CARD15 mutation (1007 fs), whereas all of the others did not carry any of the 3 common mutant alleles. This number is significantly lower (P < 0.001) than the mutation prevalence demonstrated in both pediatric and adult Israeli CD patients.

CONCLUSIONS

NOD2/CARD15 mutations are not associated with LNH. This may strengthen the lack of association between CD and LNH that has been previously reported. We suggest that genotyping NOD2/CARD15 may help to distinguish LNH from inflammatory bowel diseases in selected patients.

NOD2: Ethnic and geographic differences

Investigations into the inheritance of the three risk alleles R702W, G908R and 1007fsInsC in NOD2 associated with susceptibility to Crohn’s disease have demonstrated a remarkable amount of heterogeneity across ethnicities and populations, with regional variation across Europe for example, suggesting local founder effects. In non-Caucasian populations Crohn's disease continues to increase in incidence but this increase appears not to be a consequence of variation in NOD2, further advancing the accumulating evidence for other susceptibility loci. Frequencies of the known alleles are compared across populations in health and disease and evidence for additional alleles in NOD2 is reviewed. Based on its position on chromosome 16 coincident with some other autoimmune disease susceptibility localizations, research has targeted NOD2 variation as the potential cause of other autoimmune disorders. While these investigations have mostly returned negative findings, two diseases, Blau Syndrome and Graft versus Host Disease, have been shown to be caused by risk alleles in NOD2. As is frequent in complex disease investigations, some results await validation, but the identification of NOD2 and the differences within and across population raises intriguing questions about the population genetics of the variation at this locus.

Relationship between CARD15, SLC22A4/5, and DLG5 polymorphisms and early-onset inflammatory bowel diseases: an Italian multicentric study

BACKGROUND

Inflammatory bowel disease (IBD) has been associated with several polymorphisms in genes likely involved in innate immune responses and integrity of epithelial mucosal barrier. A major role in adult Crohn's disease (CD) has been defined for 3 polymorphisms in the CARD15 gene, whereas variants in the SLC22A4, SLC22A5, and DLG5 genes could have a minor contribution to IBD susceptibility.

METHODS

We analyzed a panel of 6 polymorphisms within these genes in 227 Italian early-onset IBD patients (134 CD, 93 ulcerative colitis [UC]; age at diagnosis <or=18 years) and 166 unaffected control subjects.

RESULTS

Each CARD15 variant was found to be independently associated with CD. After the genotypes at the 3 polymorphisms were combined, 37.3% patients carried at least 1 variant compared with 9.2% control subjects (odds ratio, 5.87; 95% CI 3.11-11.1; P < 0.001). The combined frequency of CARD15 variants was also higher in UC children compared with control subjects (14% vs 9.2%), but this difference was not significant. However, CARD15 variants were associated with earlier onset of UC, and the mutation rate was significantly higher in UC patients with onset at or before 6 years of age compared with control subjects (27.6% vs 9.2%) (odds ratio = 3.76; 95% CI 1.42-9.94; P = 0.01). CARD15 variants also were associated with ileal CD involvement and a higher rate of extraintestinal manifestations in UC. Allele and genotype frequencies at SLC22A and DLG5 polymorphisms were not significantly different between cases and controls.

CONCLUSIONS

Our results demonstrate that in the Italian population, the major CARD15 polymorphisms are associated with susceptibility to early-onset CD and with ileal involvement and suggest a previously unreported association with very early-onset, severe UC.

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.

Molekulare Therapie in der Gastroenterologie und Hepatologie

During recent years, molecular techniques have significantly impacted our understanding and therapeutic concepts in gastrointestinal and liver disease. In a number of diseases, diagnostic work-up includes molecular data that supplements the phenotypical evaluation. This includes monogenic diseases as well as the identification of genetic risk factors (e. g. NOD2/CARD15 mutation in Crohn's disease) and viral disease. Attempts to replace liver transplantation in hereditary liver disease by targeted molecular interventions (e. g. via viral vectors) are still experimental, but the associated techniques have improved considerably. The molecular identification of therapeutic targets was followed by the development of specifically tailored therapeutics. These agents are mainly used in the treatment of chronic inflammatory bowel disease and gastrointestinal tumors.

Advances in the genetics of inflammatory bowel disease

Research efforts in the inflammatory bowel diseases have been uniquely successful in identifying genetic linkage regions likely containing susceptibility genes for Crohn's disease and ulcerative colitis. In two of these regions, definitive gene associations have been established, namely for the NOD2/CARD15 gene on chromosome 16 (IBD1) and the OCTN1/SLC22A4-OCT/SLC22A5 genes on chromosome 5q (IBD5), both conferring increased risk for developing Crohn's disease. Recently, significant gene associations have been reported for additional genes, including DLG5, MDR1, and TLR4 as well. The NOD2/CARD15 gene mutations are associated with ileal disease location and a modestly earlier age of onset compared with NOD2/CARD15 wild-type Crohn's disease patients. Future progress in the genetics of inflammatory bowel disease will likely involve systematic phenotyping, including the incorporation of clinical subtypes and novel biomarkers. The ultimate goal of genetic research in inflammatory bowel disease is to identify the earliest biologic pathways that are altered, resulting in disease pathogenesis. Identification of these key pathways will potentially highlight novel therapeutic targets.