Orazio Palmieri

Genome-wide association identifies multiple ulcerative colitis susceptibility loci

Ulcerative colitis is a chronic, relapsing inflammatory condition of the gastrointestinal tract with a complex genetic and environmental etiology. In an effort to identify genetic variation underlying ulcerative colitis risk, we present two distinct genome-wide association studies of ulcerative colitis and their joint analysis with a previously published scan, comprising, in aggregate, 2,693 individuals with ulcerative colitis and 6,791 control subjects. Fifty-nine SNPs from 14 independent loci attained an association significance of P < 10−5. Seven of these loci exceeded genome-wide significance (P < 5 × 10−8). After testing an independent cohort of 2,009 cases of ulcerative colitis and 1,580 controls, we identified 13 loci that were significantly associated with ulcerative colitis (P < 5 × 10−8), including the immunoglobulin receptor gene FCGR2A, 5p15, 2p16 and ORMDL3 (orosomucoid1-like 3). We confirmed association with 14 previously identified ulcerative colitis susceptibility loci, and an analysis of acknowledged Crohns disease loci showed that roughly half of the known Crohns disease associations are shared with ulcerative colitis. These data implicate approximately 30 loci in ulcerative colitis, thereby providing insight into disease pathogenesis.

A meta-analysis of genome-wide association scans identifies IL18RAP, PTPN2, TAGAP, and PUS10 as shared risk loci for Crohn's disease and celiac disease

Crohns disease (CD) and celiac disease (CelD) are chronic intestinal inflammatory diseases, involving genetic and environmental factors in their pathogenesis. The two diseases can co-occur within families, and studies suggest that CelD patients have a higher risk to develop CD than the general population. These observations suggest that CD and CelD may share common genetic risk loci. Two such shared loci, IL18RAP and PTPN2, have already been identified independently in these two diseases. The aim of our study was to explicitly identify shared risk loci for these diseases by combining results from genome-wide association study (GWAS) datasets of CD and CelD. Specifically, GWAS results from CelD (768 cases, 1,422 controls) and CD (3,230 cases, 4,829 controls) were combined in a meta-analysis. Nine independent regions had nominal association p-value <1.0×10−5 in this meta-analysis and showed evidence of association to the individual diseases in the original scans (p-value <1×10−2 in CelD and <1×10−3 in CD). These include the two previously reported shared loci, IL18RAP and PTPN2, with p-values of 3.37×10−8 and 6.39×10−9, respectively, in the meta-analysis. The other seven had not been reported as shared loci and thus were tested in additional CelD (3,149 cases and 4,714 controls) and CD (1,835 cases and 1,669 controls) cohorts. Two of these loci, TAGAP and PUS10, showed significant evidence of replication (Bonferroni corrected p-values <0.0071) in the combined CelD and CD replication cohorts and were firmly established as shared risk loci of genome-wide significance, with overall combined p-values of 1.55×10−10 and 1.38×10−11 respectively. Through a meta-analysis of GWAS data from CD and CelD, we have identified four shared risk loci: PTPN2, IL18RAP, TAGAP, and PUS10. The combined analysis of the two datasets provided the power, lacking in the individual GWAS for single diseases, to detect shared loci with a relatively small effect.

Genetic variants in the region harbouring IL2/IL21 associated with ulcerative colitis

Objectives: Genetic susceptibility is known to play a large part in the predisposition to the inflammatory bowel diseases (IBDs) known as Crohn’s disease (CD) and ulcerative colitis (UC). The IL2/IL21 locus on 4q27 is known to be a common risk locus for inflammatory disease (shown in coeliac disease, type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus and psoriasis), while the roles that interleukin 2 (IL2) and IL21 play in the immune response also make them attractive candidates for IBD. The objective of this study was to test for association between the IL2/IL21 locus and the IBDs. Methods: The four single nucleotide polymorphisms (SNPs) in the IL2/IL21 locus most associated with coeliac disease were genotyped in 1590 subjects with IBD and 929 controls from The Netherlands, and then replicated in a North American cohort (2387 cases and 1266 controls) and an Italian cohort (805 cases and 421 controls), yielding a total of 4782 cases (3194 UC, 1588 CD) and 2616 controls. Allelic association testing and a pooled analysis using a Cochran–Mantel–Haenszel test were performed. Results: All four SNPs were strongly associated with UC in all three cohorts and reached genome-wide significance in the pooled analysis (rs13151961 p = 1.35×10−10, rs13119723 p = 8.60×10−8, rs6840978 p = 3.07×10−8, rs6822844 p = 2.77×10−9). A moderate association with CD was also found in the pooled analysis (p value range 0.0016–9.86×10−5). Conclusions: A strong association for the IL2/IL21 locus with UC was found, which also confirms it as a general susceptibility locus for inflammatory disease.

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

BACKGROUND:Three major variants of the CARD15 gene confer susceptibility to Crohns disease (CD). Whether or not these variants correlate with specific clinical features of the disease is under evaluation.AIM:We investigated the possible association of CARD15 variants with specific clinical characteristics, including the occurrence of anti-Saccharomyces cerevisiae antibodies (ASCA) and antineutrophil cytoplasmic antibodies (ANCA), in a large cohort of inflammatory bowel disease (IBD) patients and their unaffected relatives.METHODS:Three hundred and sixteen CD patients (156 with positive family history), 408 ulcerative colitis (UC) patients (206 with positive family history), 588 unaffected relatives, and 205 unrelated healthy controls (HC) were studied. Single nucleotide polymorphisms (SNPs) R702W, G908R, and L1007finsC of the CARD15 gene were investigated and correlated to age at diagnosis, gender, family history, localization, extraintestinal manifestations, previous resective surgery, stenosing/fistulizing pattern, ANCA, and ASCA.RESULTS:Compared to HC, the frequencies of all three variants in CD were significantly increased: 8.7%versus 4.1% for R702W (p < 0.006), 7.3%versus 2.7% for G908R (p < 0.002), 9.3%versus 0.7% for L1007finsC (p < 0.00001). At least one risk allele was found in 38.2% (p < 0.0001, compared to HC), 13.7% (NS), and 15.1% of CD, UC, and HC, respectively. The L1007finsC risk allele was also significantly increased in unaffected relatives of familial (9.5%; p < 0.00001), and sporadic CD (9%; p < 0.00001), compared to HC (0.7%). Sixteen healthy relatives, carriers of two risk alleles, were asymptomatic after 5–8 yr of follow-up. CD carriers of at least one variant were younger (p= 0.03), more likely to have ileal localization (p= 0.0001), stenosing pattern (p= 0.01), previous resective surgery (p= 0.0001), and presence of ASCA (p= 0.0001). No difference in SNPs frequency between familial and sporadic cases of CD was found.CONCLUSIONS:In our population, both familial and sporadic CD patients carrying at least one major variant of CARD15 had an aggressive clinical course.

Polymorphisms of tumor necrosis factor-α 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)-α 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-α 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-α 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-α 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.

Variants of OCTN1-2 cation transporter genes are associated with both Crohn's disease and ulcerative colitis

Background  Two variants in the organic cation transporter gene cluster have been recently reported to confer susceptibility to Crohns disease (CD).

Multidrug resistance 1 gene polymorphisms are not associated with inflammatory bowel disease and response to therapy in Italian patients

Background : Host genetic factors may be important in determining not only disease susceptibility, but also disease behaviour and response to therapy in inflammatory bowel disease. Two polymorphisms (C3435T and G2677T/A) of the multidrug resistance 1 gene have been correlated with the altered P‐glycoprotein expression and function in humans, and associated with predisposition to ulcerative colitis and Crohns disease.

Erythrocyte-Mediated Delivery of Dexamethasone in Patients With Mild-to-Moderate Ulcerative Colitis, Refractory to Mesalamine: A Randomized, Controlled Study

BACKGROUND AND AIM:Nearly 25% of patients with ulcerative colitis (UC) requiring steroids therapy become steroid-dependent after 1 yr, and virtually all develop steroid-related adverse events. We planned a controlled study to investigate the efficacy and safety of dexamethasone 21-P (Dex 21-P) encapsulated into erythrocytes (DEE).MATERIALS AND METHODS: Forty patients with mild-to-moderate UC, refractory to mesalamine, were randomly assigned to one of the following three treatments: two DEE infusions 14 days apart (group A, N = 20), oral prednisolone (0.5 mg/kg for 14 days followed by a 6 mg/weekly tapering (group B, N = 10), and sham infusions (group C, N = 10). The clinical, biochemical, and endoscopic parameters were monitored at inclusion and after 8 wk.RESULTS:In group A, a mean dose of 9.9 ± 4.1 mg Dex 21-P was loaded into autologous erythrocytes at each infusion. At 8 wk, 15 patients in group A (75%), 8 in group B (80%), and 1 in group C (10%, P < 0.001 vs A and B) were in clinical and endoscopic remission. When compared with the baseline values, C-reactive protein (CRP) dropped in groups A (1.6 mg/dL vs 0.4 mg/dL, P= 0.006) and B (1.0 vs 0.5, P= 0.02), but not in group C. No steroid-related adverse events were apparent in the patient treated with DEE, compared with 8 out of 10 patients on oral steroids (P≤ 0.01).CONCLUSION:Low doses of Dex (mean total dose ± 20 mg) loaded into autologous erythrocytes were significantly more effective than sham infusions in terms of symptoms relief, endoscopic, and biochemical improvements in UC patients refractory to mesalamine. In addition, in contrast to oral prednisolone (mean total dose ± 1 g), no steroid-related adverse events were induced.

Gender-stratified analysis of DLG5 R30Q in 4707 patients with Crohn disease and 4973 controls from 12 Caucasian cohorts

Background: DLG5 p.R30Q has been reported to be associated with Crohn disease (CD), but this association has not been replicated in most studies. A recent analysis of gender-stratified data from two case–control studies and two population cohorts found an association of DLG5 30Q with increased risk of CD in men but not in women and found differences between 30Q population frequencies for males and females. Male–female differences in population allele frequencies and male-specific risk could explain the difficulty in replicating the association with CD. Methods: DLG5 R30Q genotype data were collected for patients with CD and controls from 11 studies that did not include gender-stratified allele counts in their published reports and tested for male–female frequency differences in controls and for case–control frequency differences in men and in women. Results: The data showed no male–female allele frequency differences in controls. An exact conditional test gave marginal evidence that 30Q is associated with decreased risk of CD in women (p = 0.049, OR = 0.87, 95% CI 0.77 to 1.00). There was also a trend towards reduced 30Q frequencies in male patients with CD compared with male controls, but this was not significant at the 0.05 level (p = 0.058, OR = 0.87, 95% CI 0.74 to 1.01). When data from this study were combined with previously published, gender-stratified data, the 30Q allele was found to be associated with decreased risk of CD in women (p = 0.010, OR = 0.86, 95% CI 0.76 to 0.97), but not in men. Conclusion: DLG5 30Q is associated with a small reduction in risk of CD in women.

Investigation of Multiple Susceptibility Loci for Inflammatory Bowel Disease in an Italian Cohort of Patients

Background Recent GWAs and meta-analyses have outlined about 100 susceptibility genes/loci for inflammatory bowel diseases (IBD). In this study we aimed to investigate the influence of SNPs tagging the genes/loci PTGER4, TNFSF15, NKX2-3, ZNF365, IFNG, PTPN2, PSMG1, and HLA in a large pediatric- and adult-onset IBD Italian cohort. Methods Eight SNPs were assessed in 1,070 Crohns disease (CD), 1,213 ulcerative colitis (UC), 557 of whom being diagnosed at the age of ≤16 years, and 789 healthy controls. Correlations with sub-phenotypes and major variants of NOD2 gene were investigated. Results The SNPs tagging the TNFSF15, NKX2-3, ZNF365, and PTPN2 genes were associated with CD (P values ranging from 0.037 to 7×10−6). The SNPs tagging the PTGER4, NKX2-3, ZNF365, IFNG, PSMG1, and HLA area were associated with UC (P values 0.047 to 4×10−5). In the pediatric cohort the associations of TNFSF15, NKX2-3 with CD, and PTGER4, NKX2-3, ZNF365, IFNG, PSMG1 with UC, were confirmed. Association with TNFSF15 and pediatric UC was also reported. A correlation with NKX2-3 and need for surgery (P  =  0.038), and with HLA and steroid-responsiveness (P  =  0.024) in UC patients was observed. Moreover, significant association in our CD cohort with TNFSF15 SNP and colonic involvement (P  =  0.021), and with ZNF365 and ileal location (P  =  0.024) was demonstrated. Conclusions We confirmed in a large Italian cohort the associations with CD and UC of newly identified genes, both in adult and pediatric cohort of patients, with some influence on sub-phenotypes.