Two-stage genome-wide methylation profiling in childhood-onset Crohn's Disease implicates epigenetic alterations at the VMP1/MIR21 and HLA loci.

BACKGROUND: As a result of technological and analytical advances, genome-wide characterization of key epigenetic alterations is now feasible in complex diseases. We hypothesized that this may provide important insights into gene-environmental interactions in Crohn's disease (CD) and is especially pertinent to early onset disease. METHODS: The Illumina 450K platform was applied to assess epigenome-wide methylation profiles in circulating leukocyte DNA in discovery and replication pediatric CD cohorts and controls. Data were corrected for differential leukocyte proportions. Targeted replication was performed in adults using pyrosequencing. Methylation changes were correlated with gene expression in blood and intestinal mucosa. RESULTS: We identified 65 individual CpG sites with methylation alterations achieving epigenome-wide significance after Bonferroni correction (P < 1.1 × 10(-7)), and 19 differently methylated regions displaying unidirectional methylation change. There was a highly significant enrichment of methylation changes around GWAS single nucleotide polymorphisms (P = 3.7 × 10(-7)), notably the HLA region and MIR21. Two-locus discriminant analysis in the discovery cohort predicted disease in the pediatric replication cohort with high accuracy (area under the curve, 0.98). The findings strongly implicate the transcriptional start site of MIR21 as a region of extended epigenetic alteration, containing the most significant individual probes (P = 1.97 × 10(-15)) within a GWAS risk locus. In extension studies, we confirmed hypomethylation of MIR21 in adults (P = 6.6 × 10(-5), n = 172) and show increased mRNA expression in leukocytes (P < 0.005, n = 66) and in the inflamed intestine (P = 1.4 × 10(-6), n = 99). CONCLUSIONS: We demonstrate highly significant and replicable differences in DNA methylation in CD, defining the disease-associated epigenome. The data strongly implicate known GWAS loci, with compelling evidence implicating MIR21 and the HLA region.

Genome-wide methylation profiling in Crohn's disease identifies altered epigenetic regulation of key host defense mechanisms including the Th17 pathway.

BACKGROUND: Germline variation in the 71 Crohn's disease (CD) loci implicated by genome-wide association studies (GWAS) only accounts for approximately 25% of estimated heritability. The contribution of epigenetic alterations to disease pathogenesis is emerging as a research priority. MATERIALS AND METHODS: The methylation status of 27,578 CpG sites across the genome was analyzed using the Illumina Human Methylation27 assay in DNA extracted from whole blood samples from 40 adult females (21 ileal CD, 19 healthy controls) and 16 girls with childhood-onset CD, all nonsmokers. Our primary analysis compared methylation profiles in adult cases and controls. RESULTS: Our data define a global methylation profile characteristic of ileal CD. In all, 1117 sites were differentially methylated (corrected P < 0.01); 50 showed significantly altered methylation in cases compared with controls (uncorrected P < 10(-6), corrected P < 0.0006), including genes altering immune activation: MAPK13, FASLG, PRF1, S100A13, RIPK3, and IL-21R. Gene ontology analyses implicated immunity-related pathways as targets of epigenetic modification (immune system processes [P = 1.3 × 10(-22)], immune response [P = 8.1 × 10(-16)], defense responses to bacteria [P = 1.8 × 10(-15)]). Ingenuity canonical pathway analyses implicated dendritic cell activity (P = 2.4 × 10(-8)) and differential regulation of cytokines by interleukin (IL)-17A and IL-17F (P = 5.8 × 10(-7)). We identified a significant enrichment of methylation changes within 50 kb of CD GWAS loci (8.6-fold [P = 0.021] in adults; 2.4-fold [P = 0.009] in adults and children combined), including IL-27, IL-19, TNF, MST1, and NOD2. Methylation status was predictive of disease status (sensitivity 0.71, specificity 0.83). Disease activity, drug therapy, NOD2 and DNMT3A genotypes were not associated with methylation changes. CONCLUSIONS: These data provide an important insight into the impact of epigenetic mechanisms in the pathogenesis of CD.

Rising incidence of pediatric inflammatory bowel disease in Scotland.

BACKGROUND: An accurate indication of the changing incidence of pediatric inflammatory bowel disease (PIBD) within a population is useful in understanding concurrent etiological factors. We aimed to compare the current incidence and other demographic attributes of PIBD in the Scottish population to previous data. METHODS: A national cohort of prospectively and retrospectively acquired incident cases of PIBD diagnosed less than 16 years old in pediatric services in Scotland was captured for the period 2003-2008; historical Scottish data were used for comparison (1990-1995). Age/sex-adjusted incidences were calculated and statistical comparisons made using Poisson regression. RESULTS: During the 2003-2008 study period 436 patients were diagnosed with PIBD in Scotland, giving an adjusted incidence of 7.82/100,000/year. The incidence of Crohn's disease (CD) was 4.75/100,000/year, ulcerative colitis (UC) 2.06/100,000/year, and inflammatory bowel disease-unclassified (IBDU) 1.01/100,000/year. Compared with data from 1990-1995 when 260 IBD patients were diagnosed, significant rises in the incidence of IBD (from 4.45/100,000/year, P < 0.0001), CD (from 2.86/100,000/year, P < 0.0001), and UC (from 1.59/100,000/year, P = 0.023) were seen. There was also a significant reduction in the median age at IBD diagnosis from 12.7 years to 11.9 years between the periods (P = 0.003), with a continued male preponderance. CONCLUSIONS: The number of Scottish children diagnosed with IBD continues to rise, with a statistically significant 76% increase since the mid-1990 s. Furthermore, PIBD is now being diagnosed at a younger age. The reason for this continued rise is not yet clear; however, new hypotheses regarding disease pathogenesis and other population trends may provide further insights in future years.

TLE1 modifies the effects of NOD2 in the pathogenesis of Crohn's disease.

BACKGROUND & AIMS: The mechanisms by which specific mutations in NOD2/CARD15 increase the risk for Crohn's disease (CD) are unclear. We identified proteins that interact with NOD2 and investigated them by expression, genetic, and functional analyses. METHODS: By using a yeast 2-hybrid screen of an intestinal epithelial library, we identified proteins that interact with NOD2 and confirmed the interactions in mammalian cells using co-immunoprecipitation. We used microarray analysis to analyze gene expression patterns in 302 intestinal biopsy samples (129 from patients with ulcerative colitis [UC], 106 with CD, and 67 controls). Eighty single-nucleotide polymorphisms within the genes that encoded 6 interacting proteins were genotyped in a discovery cohort (869 cases of inflammatory bowel disease [IBD], 885 controls) and a replication cohort (504 patients with IBD, 713 controls). We investigated interaction between transducin-like enhancer of split 1 (TLE1) and NOD2 in HEK293 cells. RESULTS: We identified 6 NOD2-interacting proteins (TLE1, UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 2 [GALNT2], HIV-1 Tat interactive protein [HTATIP], Vimentin, fission 1 (mitochondrial outer membrane) homolog [FIS1], and protein phosphatase 2, regulatory subunit B', epsilon isoform [PPP2R5E]). Of these, expression of GALNT2 (CD, P = .004) and vimentin (CD, P = .006; UC, P = .0025) was altered in patients with IBD compared with controls. Single-nucleotide polymorphisms within TLE1 were associated with susceptibility to CD, specifically with ileal disease (rs6559629, P = 3.1 × 10⁻5; odds ratio, 1.45). The TLE1 risk allele is required for susceptibility to CD in carriers of NOD2 mutations. In cells, TLE1 and NOD2 co-localized around the nuclear membrane and TLE1 inhibited activation of nuclear factor-κB by NOD2. CONCLUSIONS: Epistatic and biological interactions between TLE1 and NOD2 are involved in IBD pathogenesis. NOD2 might be involved in a series of pathways such as epigenetic regulation of expression (via TLE1 and HTATIP), biosynthesis of mucin (via GALNT2), apoptosis (via PPP2R5E and FIS1), and integrity of the intracellular cytoskeleton (vimentin).

Genome-wide association study of CNVs in 16,000 cases of eight common diseases and 3,000 shared controls.

Copy number variants (CNVs) account for a major proportion of human genetic polymorphism and have been predicted to have an important role in genetic susceptibility to common disease. To address this we undertook a large, direct genome-wide study of association between CNVs and eight common human diseases. Using a purpose-designed array we typed approximately 19,000 individuals into distinct copy-number classes at 3,432 polymorphic CNVs, including an estimated approximately 50% of all common CNVs larger than 500 base pairs. We identified several biological artefacts that lead to false-positive associations, including systematic CNV differences between DNAs derived from blood and cell lines. Association testing and follow-up replication analyses confirmed three loci where CNVs were associated with disease-IRGM for Crohn's disease, HLA for Crohn's disease, rheumatoid arthritis and type 1 diabetes, and TSPAN8 for type 2 diabetes-although in each case the locus had previously been identified in single nucleotide polymorphism (SNP)-based studies, reflecting our observation that most common CNVs that are well-typed on our array are well tagged by SNPs and so have been indirectly explored through SNP studies. We conclude that common CNVs that can be typed on existing platforms are unlikely to contribute greatly to the genetic basis of common human diseases.

Fecal calprotectin complements routine laboratory investigations in diagnosing childhood inflammatory bowel disease.

BACKGROUND: We aimed to study fecal calprotectin in Scottish children with inflammatory bowel disease (IBD) and compare its diagnostic accuracy with blood parameters. METHODS: Stool samples from 48 Scottish children (29 males, 19 females) had calprotectin measured at IBD diagnosis. The median age at diagnosis was 11.2 years (interquartile range [IQR] 8.7-13.0 years). There were 33 patients with Crohn's disease, 5 with ulcerative colitis, and 10 with IBD type unspecified. IBD was diagnosed by standard criteria. Calprotectin was measured using a commercially available kit (PhiCal Test) and 47/48 patients had comparative blood results available at diagnosis. RESULTS: The fecal calprotectin concentrations were raised in 96% (46/48) of patients studied. The median calprotectin value was 750 microg/g (IQR 235.8-1251 microug/g). In comparison with standard blood tests, 32/45 (71.1%) had abnormal erythrocyte sedimentation rate, 19/38 (50.0%) had abnormal C-reactive protein, 29/46 (63.0%) had raised platelets, 12/45 (26.7%) had hypoalbuminemia, and 38/46 (82.6%) had abnormal hemoglobin. We identified 7/47 (14.9%) patients with raised calprotectin at diagnosis who did not have any abnormalities detected in the blood tests performed. All 48 patients (100%) had at least 1 abnormal blood test and/or raised calprotectin at diagnosis. CONCLUSIONS: Calprotectin is significantly more likely to be raised than any commonly employed blood tests at IBD diagnosis. When used in combination with these bloods tests an abnormality was demonstrated in 1 or both tests in all patients at diagnosis in this study. Fecal calprotectin measurement is a significant advance when used contemporaneously and in addition to a routine panel of blood tests in the diagnosis of pediatric IBD.

Analysis of germline GLI1 variation implicates hedgehog signalling in the regulation of intestinal inflammatory pathways.

BACKGROUND: Ulcerative colitis (UC) and Crohn's disease (CD) are polygenic chronic inflammatory bowel diseases (IBD) of high prevalence that are associated with considerable morbidity. The hedgehog (HH) signalling pathway, which includes the transcription factor glioma-associated oncogene homolog 1 (GLI1), plays vital roles in gastrointestinal tract development, homeostasis, and malignancy. We identified a germline variation in GLI1 (within the IBD2 linkage region, 12q13) in patients with IBD. Since this IBD-associated variant encodes a GLI1 protein with reduced function and our expression studies demonstrated down-regulation of the HH response in IBD, we tested whether mice with reduced Gli1 activity demonstrate increased susceptibility to chemically induced colitis. METHODS AND FINDINGS: Using a gene-wide haplotype-tagging approach, germline GLI1 variation was examined in three independent populations of IBD patients and healthy controls from Northern Europe (Scotland, England, and Sweden) totalling over 5,000 individuals. On log-likelihood analysis, GLI1 was associated with IBD, predominantly UC, in Scotland and England (p < 0.0001). A nonsynonymous SNP (rs2228226C-->G), in exon 12 of GLI1 (Q1100E) was strongly implicated, with pooled odds ratio of 1.194 (confidence interval = 1.09-1.31, p = 0.0002). GLI1 variants were tested in vitro for transcriptional activity in luciferase assays. Q1100E falls within a conserved motif near the C terminus of GLI1; the variant GLI protein exhibited reduced transactivation function in vitro. In complementary expression studies, we noted the colonic HH response, including GLI1, patched (PTCH), and hedgehog-interacting protein (HHIP), to be down-regulated in patients with UC. Finally, Gli1(+/lacZ) mice were tested for susceptibility to dextran sodium sulphate (DSS)-induced colitis. Clinical response, histology, and expression of inflammatory cytokines and chemokines were recorded. Gli1(+/lacZ) mice rapidly developed severe intestinal inflammation, with considerable morbidity and mortality compared with wild type. Local myeloid cells were shown to be direct targets of HH signals and cytokine expression studies revealed robust up-regulation of IL-12, IL-17, and IL-23 in this model. CONCLUSIONS: HH signalling through GLI1 is required for appropriate modulation of the intestinal response to acute inflammatory challenge. Reduced GLI1 function predisposes to a heightened myeloid response to inflammatory stimuli, potentially leading to IBD.

Definition of phenotypic characteristics of childhood-onset inflammatory bowel disease.

BACKGROUND & AIMS: Childhood-onset inflammatory bowel disease (IBD) might be etiologically different from adult-onset IBD. We analyzed disease phenotypes and progression of childhood-onset disease and compared them with characteristics of adult-onset disease in patients in Scotland. METHODS: Anatomic locations and behaviors were assessed in 416 patients with childhood-onset (276 Crohn's disease [CD], 99 ulcerative colitis [UC], 41 IBD type unclassified [IBDU] diagnosed before seventeenth birthday) and 1297 patients with adult-onset (596 CD, 701 UC) IBD using the Montreal classification. RESULTS: At the time of diagnosis in children, CD involved small bowel and colon (L3) in 51% (138/273), colon (L2) in 36%, and ileum (L1) in 6%; the upper gastrointestinal (GI) tract (L4) was also affected in 51%. In 39%, the anatomic extent increased within 2 years. Behavioral characteristics progressed; 24% of children developed stricturing or penetrating complications within 4 years (vs 9% at diagnosis; P < .0001; odds ratio [OR], 3.32; 95% confidence interval [CI], 1.86-5.92). Compared with adults, childhood-onset disease was characterized by a "panenteric" phenotype (ileocolonic plus upper GI [L3+L4]; 43% vs 3%; P < .0001; OR, 23.36; 95% CI, 13.45-40.59) with less isolated ileal (L1; 2% vs 31%; P < .0001; OR, 0.06; 95% CI, 0.03-0.12) or colonic disease (L2; 15% vs 36%; P < .0001; OR, 0.31; 95% CI, 0.21-0.46). UC was extensive in 82% of the children at diagnosis, versus 48% of adults (P < .0001; OR, 5.08; 95% CI, 2.73-9.45); 46% of the children progressed to develop extensive colitis during follow-up. Forty-six percent of children with CD and 35% with UC required immunomodulatory therapy within 12 months of diagnosis. The median time to first surgery was longer in childhood-onset than adult-onset patients with CD (13.7 vs 7.8 years; P < .001); the reverse was true for UC. CONCLUSIONS: Childhood-onset IBD is characterized by extensive intestinal involvement and rapid early progression.

Investigation of NOD1/CARD4 variation in inflammatory bowel disease using a haplotype-tagging strategy.

Both NOD1/CARD4 and NOD2/CARD15 are intracellular pattern-recognition receptors involved in the innate immune response. Germline NOD2/CARD15 variation has a definite effect on susceptibility to Crohn's disease (CD) and phenotype, although this contribution is weak in Scotland and Scandinavia. The NOD1/CARD4 gene lies within the putative inflammatory bowel disease (IBD) locus at 7p14.3. We have assessed, in detail, the influence of germline NOD1/CARD4 variation on IBD susceptibility and phenotype in the Scottish population. Two thousand two hundred and ninety-six subjects, including 356 children with IBD, were involved in parallel case-control and family-based association studies. Nine tagging single-nucleotide polymorphisms (SNPs) were selected based on HapMap data spanning the whole of the NOD1/CARD4 gene. Our case-control SNP analysis was powered to detect an effect size with OR 1.5 for IBD and OR 1.6 for CD. No significant associations were observed between any of nine the NOD1/CARD4 SNPs studied and IBD, CD or ulcerative colitis (UC) (P > 0.05 for all). Haplotype case-control analysis was also negative (P > 0.05 in IBD, CD and UC). Multimarker transmission disequilibrium testing analysis was negative (P > 0.05 in IBD, CD and UC). NOD2/CARD15 variant carriage had no influence on NOD1/CARD4 effect on IBD susceptibility. This study represents the first application of a gene -wide haplotype-tagging approach to assess, in detail, the contribution of NOD1/CARD4 in IBD.

Does cigarette smoking influence the phenotype of Crohn's disease? Analysis using the Montreal classification.

OBJECTIVES: The clinical subclassification of Crohn's disease by phenotype has recently been reevaluated. We have investigated the relationships between smoking habit, age at diagnosis, disease location, and progression to stricturing or penetrating complications using the Montreal classification. METHODS: 408 patients (157 male, median age 29.4 yr) were assessed. Data were collected on smoking habit, age at diagnosis, anatomical distribution, and disease behavior. Follow-up data were available on all patients (median 10 yr). RESULTS: At diagnosis, ex-smokers (N = 53) were older than nonsmokers (N = 177) or current smokers (N = 178, medians 43.2 vs 28.3 or 28.9 yr, respectively, P < 0.001). Disease location differed according to smoking habit at diagnosis (chi(2)= 24.1, P= 0.02) as current smokers had less colonic (L2) disease than nonsmokers or ex-smokers (30%vs 45%, 50%, respectively). In univariate Kaplan-Meier survival analysis, smoking habit at diagnosis was not associated with time to development of stricturing disease, internal penetrating disease, perianal penetrating disease, or time to first surgery. Patients with isolated colonic (L2) disease were slower to develop strictures (P < 0.001) or internal penetrating disease (P= 0.001) and to require surgery (P < 0.001). Cox models with smoking habit as time-dependent covariates showed that, relative to ileal (L1) location of disease, progression to stricturing disease was less rapid for patients with colonic (L2) disease (HR 0.140, P < 0.001), but not independently affected by smoking habit. Progression to surgery was also slower for colonic (L2) than ileal (L1) disease location (HR 0.273, P < 0.001), but was independent of smoking habit. CONCLUSIONS: Smoking habit was associated with age at diagnosis and disease location in Crohn's disease, while disease location was associated with the rate of development of stricturing complications and requirement for surgery. The pathogenic basis of these observations needs to be explained.

Smoking habit and load influence age at diagnosis and disease extent in ulcerative colitis.

INTRODUCTION: Cigarette smoking affects susceptibility to ulcerative colitis (UC), but its effects on age at diagnosis, disease extent, and need for surgery are less well defined. We examined these parameters in a detailed retrospective analysis of a large cohort of well-characterized UC patients. METHODS: 499 UC patients (254 male, median age 34.3 yr) were studied. Data were collected on smoking habits, smoking load (pack-years), age at recruitment, age at diagnosis, surgery, and disease extent. Colonoscopic and histological data at both diagnosis and follow-up (median follow-up time 4.6 yr) were available on 349 patients. RESULTS: Ex-smokers were older at diagnosis than current or nonsmokers, (46.5 yr vs 31.1 or 29.4 yr, respectively, P < 0.001). Before diagnosis, ex-smokers had a higher smoking load than current smokers (13.0 vs 6.94 pack-years, P < 0.001). A Cox model for age at diagnosis, with smoking as a time-dependent covariate, showed that at any age, ex-smokers were significantly more likely to develop UC than current smokers (hazard ratio 1.8, 95% CI 1.41-2.44, P < 0.001). For current smokers at latest colonoscopy, those with extensive disease were the lightest smokers (median 0.320 pack-years), whereas those with healthy colons were the heaviest smokers (median 9.18 pack-years, P= 0.006). At 5 yr, regression of extensive disease was more frequent in current than ex-smokers or nonsmokers (30% current smokers vs 8% nonsmokers and 5% ex-smokers, chi(2)= 30.4, P < 0.001) but these differences were not maintained over a longer time period. CONCLUSIONS: Smoking habit influences the age at diagnosis and changes in disease extent in UC. Mechanisms are likely to be complex and require further investigation.

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.

Sero-reactivity to microbial components in Crohn's disease is associated with disease severity and progression, but not NOD2/CARD15 genotype.

BACKGROUND AND AIMS: Antibodies directed against the porin protein C of Escherichia coli (anti-OmpC) and Pseudomonas fluorescens (anti-I2) have recently been described in Crohn's disease (CD). Those directed against Saccharomyces cerevisiae (ASCA) and the perinuclear component of neutrophils (pANCA) have been more widely studied and may be of diagnostic importance. We aimed to assess the frequency of anti-OmpC, anti-I2, ASCA, and pANCA, in an independent Scottish CD cohort, establish phenotypic associations, and compare with a U.S. cohort. METHODS: One hundred and forty-two well-characterized CD patients (76 females, median age 39 yr (17-88)) were studied. CD was classified by the Vienna classification. Sera were assayed for anti-OmpC, anti-I2, ASCA, and pANCA. Allele specific primers were used for NOD2/CARD15 genotyping. RESULTS: Anti-OmpC, anti-I2, ASCA, and pANCA were present in sera from 37%, 52%, 39%, and 14% of CD patients, respectively. Multivariate analysis demonstrated independent associations of anti-OmpC to be progression of disease type (p= 0.005) and long disease duration (p= 0.002), and those of anti-I2 to be long disease duration (p= 0.002) and the need for surgery (p= 0.033). ASCA were associated with disease progression (p < 0.001). When the presence and magnitude of all antibody responses were considered, reactivity to microbial components was associated with long disease duration (p < 0.001), progression of disease type (p < 0.001), penetrating disease (p= 0.008), small bowel disease (p < 0.02), and the need for surgery (p < 0.001). There was no association of antibody status to NOD2/CARD15 genotype. CONCLUSION: Reactivity to microbial components is associated with severe CD characterized by small bowel involvement, frequent disease progression, longer disease duration, and greater need for intestinal surgery.

Disease location, anti-Saccharomyces cerevisiae antibody, and NOD2/CARD15 genotype influence the progression of disease behavior in Crohn's disease.

BACKGROUND: Crohn's disease (CD) is characterized by heterogeneity of phenotype. The Vienna classification can be used to classify CD, and recent data illustrate that behavior evolves over the course of the disease. Clinical and biological influences on disease progression remain unclear. We examined the associations of CD disease progression at diagnosis and for up to 20 years of follow-up. METHODS: Two hundred thirty-one well-characterized CD patients were studied. Demographic, clinical, and NOD2/CARD15 data were collected. Disease behavior according to the Vienna classification was assessed at diagnosis and for up to 20 years following diagnosis. RESULTS: At diagnosis, 70% of patients had inflammatory disease, 9% stricturing, and 21% penetrating. Early age at diagnosis was associated with ileocolonic and upper GI disease (p = 0.015), and positive anti-Saccharomyces cerevisiae antibody (ASCA) was associated with ileal involvement (p = 0.008). Smoking was relatively protective against colonic, rather than ileal involvement at diagnosis (p < 0.02). At 20 years, 92% had progressed to a more severe disease type. Patients who progress to a more severe disease type require more frequent surgery (p < 0.00001). Multivariate analysis found disease progression to be associated with ileal disease location (p = 0.001) and positive ASCA (p = 0.003). Variant NOD2/CARD15 alleles were protective against rapid progression of disease phenotype (p = 0.04). The presence of perianal disease was independent of intestinal penetrating disease. CONCLUSIONS: The progression of disease type in CD is associated with the need for more frequent surgery. Rapid progression is associated with ileal disease and positive ASCA, and delayed progression is associated with variant NOD2/CARD15 alleles. Consideration should be given to a separate Vienna classification for perianal disease.

Incidence of juvenile-onset Crohn's disease in Scotland: association with northern latitude and affluence.

BACKGROUND & AIMS: The incidence of Crohn's disease in Scottish children has increased steadily over 30 years. Many studies have investigated genetic influence or possible links with childhood events. We aimed to study sociodemographic and/or geographic distribution of juvenile=onset Crohn's disease in Scotland. METHODS: Using a previously established and validated database covering the entire Scottish population, 580 Scottish children (<16 years of age at symptom onset) with inflammatory bowel disease incident between 1981 and 1995 were identified. Postcodes of incident cases were classed for geographic location and material deprivation. Incidence rates (/100,000/year) were sex standardized to the 1991 census population. The effects of sex, geographic location, time, and deprivation category were estimated from a multifactorial Poisson regression model. RESULTS: The incidence of juvenile-onset Crohn's disease was 2.3 (95% CI: 2.0-2.5) for the time period 1981 to 1995 and was significantly higher in northern (3.1, 95% CI: 2.6-3.8) than in southern Scotland (2.1, 95% CI: 1.9-2.4, P < 0.001). The incidence of juvenile-onset ulcerative colitis did not show north/south variation ( P = 0.677). The relative risks of developing CD were significantly lower in postcode areas with deprivation categories 2-7 as compared with deprivation score 1 (most affluent, P = 0.033). This pattern was not seen for UC. CONCLUSIONS: There was an increased incidence of juvenile-onset Crohn's disease in northern compared with southern Scotland. Children from more affluent areas had a higher relative risk of developing Crohn's disease. Juvenile onset ulcerative colitis did not show north/south variation in incidence or association with affluence.