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The NOD2 insC Risk Allele is Associated With Poor Pouch Outcome Following IPAA in Patients With Ulcerative Colitis (UC)
Sa1279 The NOD2 insC Risk Allele is Associated With Poor Pouch Outcome Following IPAA in Patients With Ulcerative Colitis (UC) Andrea D. Tyler, Raquel Milgrom, Wei Xu, Joanne M. Stempak, Aleixo M. Muise, John Brumell, Bo Shen, Walter A. Koltun, Gordon R. Greenberg, Robin S. McLeod, Zane Cohen, Mark S. Silverberg Background: Inflammation of the ileal reservoir following ileal pouch-anal anastomosis (IPAA) in patients with a confirmed pre-colectomy diagnosis of UC remains a common problem that is poorly understood. Previous small studies have tentatively associated genetic polymorphisms with pouch outcome, but results have not been replicated. This study evaluates possible genetic factors associated with ileal inflammation following IPAA for UC in a large Caucasian cohort. Methods: Patients with confirmed UC who had a colectomy and IPAA, with ileostomy closure ≥1 year prior to study enrollment were recruited from Mount Sinai Hospital (n=426), the Cleveland Clinic (n=177) and Hershey Medical Center (n=99). Retrospective clinical, endoscopic and histologic information was collected in order to classify patients into 3 groups: no pouchitis (NP), pouchitis (CP) and CD-like phenotype (CDL). Genomic DNA was obtained from peripheral or clotted blood at enrollment at each site and genotyped for IBD-related SNPs. Analysis of genetic results was performed in Caucasians only using Pearson chi-square tests and logistic regression, with p-values corrected using a Bonferroni adjustment. Results: 762 patients agreed to participate in the study (NP= 518, CP=125, CDL=119). 704 patients provided DNA of whom 659 were Caucasian (NP= 445, CP=112, CDL=102). The NOD2insC (rs2066847) risk variant was significantly associated with pouch outcome (pcorr =0.048) with minor allele frequencies of 0.016 in the NP, 0.062 CP and 0.064 CDL groups. In a pairwise comparison, this variant was associated with both CP and CDL when compared to NP (OR=3.2 and 4.3 respectively). Four additional SNPs showed a trend towards significance (puncorr <0.01) however this result did not survive correction for multiple testing. These included polymorphisms at the loci: NOX3 (2 SNPs), DAGLB (1 SNP), and NCF4 (1 SNP). Conclusions: The NOD2 insC mutation was significantly associated with pouch outcome among patients with UC and IPAA. Additional loci related to genes involved in innate immune pathways were also associated with outcome but may require larger sample sizes to confirm their significance. Further study may be necessary to confirm whether the associations which we have observed have utility in identifying and managing UC patients who are at risk of developing post-surgical complications following IPAA.
Sa1277 Genome-Wide Association Study of CD-Associated Anti-Microbial Antibodies Kent D. Taylor, Talin Haritunians, Dermot P. McGovern, Carol J. Landers, Andrew Ippoliti, Eric A. Vasiliauskas, Xiuqing Guo, Marla Dubinsky, Stephan R. Targan, Jerome I. Rotter BACKGROUND. We have previously reported that CD patients can be characterized by the association of disease phenotypes with the expression of antibodies to microbial antigens. For example CD associated serologies such as ASCA, I2, CBir1 and OMPc are associated with a more aggressive course of disease and an increased chance of surgery. We have also previously demonstrated the heritable nature of these IBD associated antibodies. AIM: The aim of this study was to conduct a genome-wide association study (GWAS) on 1544 CD subjects serotyped for CD-associated antibodies (ASCA, anti-CBir1, anti-I2, and anti-OMPC). METHODS: Serum antibody expression was measured by ELISA and levels were log transformed prior to analyses. Single nucleotide polymorphism (SNP) data were generated using Illumina technology (~550K SNPs with MAF>0.05) at Cedars-Sinai Medical Center. Adjustment for population stratification was carried out using two principal components as covariates in the analyses (Eigensoft). The significance of association was tested using logistic regression for antibody positive or negative and linear regression for antibody level after transformation. To overcome multiple testing issues we defined significance to be p < 2e-07. RESULTS: At the pre-defined level of significance, we observed two significant associations: 1) Expression of anti-I2 was significantly associated with 3 SNPs spanning 90kb of chr. 15 that included the 3'region of human EST BF729345, among other ESTs (rs246336, OR for G allele and anti-I2 positivity, 1.8; p (logistic regression)=8.6e-08); and 2) Expression of anti-OMPC was significantly associated with rs6566234 on chr. 18 (beta coefficient for G allele was -0.28, p (linear regression)=1.4e-07), potentially in LD with CDH19. In addition, 3) anti-Cbir1 positivity was associated with gene AK097193 on chr. 1 (rs1022265 G allele OR for anti-CBir positivity 0.68 p (logistic regression)=7.6 e-07); and 4) ASCA positivity was associated with two SNPs on chr. 3 (rs291528 & rs291523, OR 1.9, p (logistic regression)=5e07). CONCLUSIONS: These results suggest that GWAS of serum expression to microbial antibodies may lead to discovery of novel loci affecting CD course and thus suggest targets for therapies for aggressive CD.
Sa1280 Genetics of Inflammatory Bowel Disease in Asia: Systematic Review and MetaAnalysis Siew C. Ng, Kelvin K. Tsoi, Michael A. Kamm, Bing Xia, Justin C. Wu, Francis K. L. Chan, Joseph J. Sung BACKGROUND AND AIMS: Inflammatory bowel diseases (IBD) result from an interaction between genetic and environmental factors. Preliminary findings suggest that susceptibility genes differ between IBD patients in Asia and the West. We aimed to evaluate diseasepredisposing genes in Asian IBD patients. METHODS: A systematic review and meta-analysis were performed of published studies from 1950 to 2010 using keyword searches in MEDLINE, EMBASE, EBM Reviews and BIOSIS Previews. RESULTS: 477 abstracts were identified and data extracted from 103 studies, comprising 17,976 IBD patients and 27,350 age- and sex-matched controls. Major nucleotide oligomerization domain (NOD)-2 variants in Western Crohn's disease (CD) patients were not associated with CD in Han Chinese, Japanese, South Korean, Indian and Malaysian populations. New NOD2 mutations were, however, associated with CD in Malaysians (JW1 mutation), Han Chinese and Indians (P268S). Autophagyrelated protein16-liked 1(ATG16L1) was not associated with CD in East Asians (OR 0.97; 95% CI 0.84-1.13). Interleukin (IL)-23R was associated with CD in South Koreans (OR 1.8; 95% CI 1.16-2.82) and a single nucleotide polymorphism in IL-23R, Gly149Arg, was protective of CD in Han Chinese (OR 0.3; 95% CI 0.15-0.60). Tumour necrosis factor (TNF)-SF15 polymorphisms were associated with CD (OR 2.68; 95% CI 1.86-3.86), while TNF-308 polymorphisms (OR 1.82; 95% CI 1.15-2.9), cytotoxic T lymphocyte antigen (CTLA)-4 (OR 2.75; 95% CI 1.22-6.22) and MICA allele (OR 2.41; 95% CI 1.89-3.07) were associated with ulcerative colitis (UC) in Asians. CONCLUSION: Genetic mutations of IBD in Asians differ from Caucasians. Novel genes identified in Asian IBD patients provide an opportunity to explore new disease-associated mechanisms in this population of rising incidence. Table 1: Major Findings of IBD Susceptibility Genes in Asia
Sa1278 New Genetic Associations Detected in an Exome-Wide Association Study for Toxicity Related to Thiopurine Treatments in Inflammatory Bowel Disease Maria Chaparro, William Zabala-Fernandez, Manuel Barreiro-De Acosta, Julian Panes, Maria Esteve, Montserrat Andreu, Esther Garcia-Planella, Eugeni Domènech, Ana Echarri, Daniel Carpio, Raquel Cruz, Francisco Barros, Javier P. Gisbert Background: Thiopurines are widely used to treat inflammatory bowel disease (IBD) patients but its benefits are limited by toxicity, which occurs in up to 15-30% of the patients. Several factors have been implicated in determining this adverse affects, mainly individual differences in formation of active metabolites, at least partly caused by genetic variation in the genes encoding thiopurine metabolism enzymes as TPMT. Aim: To conduct a two-stage exomewide association study to identify new genes involved in the rising of adverse effects after thiopurine treatment. Methods: 20,000 codificant single-nucleotide polymorphisms (cSNPs) in 10,000 genes were performed in a Galician (EIGA) cohort of 223 individuals diagnosed with IBD and treated with 2-2.5 mg/kg/day of azathioprine or 1-1.5 mg/kg/day of mercaptopuine, where 76 developed adverse effects versus 157 individuals displaying no side effects, a mean of 18 months after starting treatment. A second stage study that included an independent ENEIDA cohort of 344 individuals with IBD and the same treatment (85 individuals with adverse effects and 259 without side effects) was performed, genotyping by a MALDI-TOF methodology 60 cSNPs identified in the first stage with p<0.001. Results: Two SNPs in two genes showed a significant association in the combined analysis (Cochran Mantel Haenszel test): rs2228043 (p-value combined=9.59 x 10(-5); OR (95%CI)=3.74 (1.86-7.52) and rs1800124 (P-value combined=7.24 x 10(-5); OR (95%CI)=5.51 (2.1214.30). rs2228043 is in the exon 10 of the interleukin 6 signal transducer (gp130, oncostatin M receptor or IL6ST) gene, and was associated with risk of leucopenia. rs1800124 is in the exon 11 of excision repair cross-complementing rodent repair deficiency, complementation group 4 (ERCC4) gene, and was associated with pancreatitis. Conclusions: An exome-wide association study identified two new associations outside thiopurine metabolism pathways. Genetic variants in ILST and ERCC4 genes were associated with leucopenia and pancreatitis in patients treated with thiopurines. These findings might help to understand the biological reasons behind thiopurine toxicity, although they should be validated in larger and more diverse cohorts
NS: not studied + Associated - Not associated
S-271
AGA Abstracts
AGA Abstracts
1.97x10-7, OR=1.77). An additional three SNPs within this region are also found to be associated with nominal significance (p<10-5); and (2) at a second region on chr.4, ~37 Mb away, with the combined ASCA, I2, CBir1 and Ompc Z-score (rs2995965 plinear= 1.35x10-9, β=0.82; rs1863284 plinear=1.71x10-7, β=0.85; rs2911920 plinear=6.29x10-6, β=0.61). RELL1, a homologue of RELT the TNF receptor that induces epithelial cell apoptosis is located at this locus. Conclusions: These observations suggest that these two loci contribute to the phenotypic difference of UC patients, one for UC severity as typified by ANCA level, the other for the expression of antibodies more characteristic of CD. Studies to assess the phenotypic differences tagged by these SNPs within the UC population are in progress.
Sa1277 Genome-Wide Association Study of CD-Associated Anti-Microbial Antibodies Kent D. Taylor, Talin Haritunians, Dermot P. McGovern, Carol J. Landers, Andrew Ippoliti, Eric A. Vasiliauskas, Xiuqing Guo, Marla Dubinsky, Stephan R. Targan, Jerome I. Rotter BACKGROUND. We have previously reported that CD patients can be characterized by the association of disease phenotypes with the expression of antibodies to microbial antigens. For example CD associated serologies such as ASCA, I2, CBir1 and OMPc are associated with a more aggressive course of disease and an increased chance of surgery. We have also previously demonstrated the heritable nature of these IBD associated antibodies. AIM: The aim of this study was to conduct a genome-wide association study (GWAS) on 1544 CD subjects serotyped for CD-associated antibodies (ASCA, anti-CBir1, anti-I2, and anti-OMPC). METHODS: Serum antibody expression was measured by ELISA and levels were log transformed prior to analyses. Single nucleotide polymorphism (SNP) data were generated using Illumina technology (~550K SNPs with MAF>0.05) at Cedars-Sinai Medical Center. Adjustment for population stratification was carried out using two principal components as covariates in the analyses (Eigensoft). The significance of association was tested using logistic regression for antibody positive or negative and linear regression for antibody level after transformation. To overcome multiple testing issues we defined significance to be p < 2e-07. RESULTS: At the pre-defined level of significance, we observed two significant associations: 1) Expression of anti-I2 was significantly associated with 3 SNPs spanning 90kb of chr. 15 that included the 3'region of human EST BF729345, among other ESTs (rs246336, OR for G allele and anti-I2 positivity, 1.8; p (logistic regression)=8.6e-08); and 2) Expression of anti-OMPC was significantly associated with rs6566234 on chr. 18 (beta coefficient for G allele was -0.28, p (linear regression)=1.4e-07), potentially in LD with CDH19. In addition, 3) anti-Cbir1 positivity was associated with gene AK097193 on chr. 1 (rs1022265 G allele OR for anti-CBir positivity 0.68 p (logistic regression)=7.6 e-07); and 4) ASCA positivity was associated with two SNPs on chr. 3 (rs291528 & rs291523, OR 1.9, p (logistic regression)=5e07). CONCLUSIONS: These results suggest that GWAS of serum expression to microbial antibodies may lead to discovery of novel loci affecting CD course and thus suggest targets for therapies for aggressive CD.
Sa1280 Genetics of Inflammatory Bowel Disease in Asia: Systematic Review and MetaAnalysis Siew C. Ng, Kelvin K. Tsoi, Michael A. Kamm, Bing Xia, Justin C. Wu, Francis K. L. Chan, Joseph J. Sung BACKGROUND AND AIMS: Inflammatory bowel diseases (IBD) result from an interaction between genetic and environmental factors. Preliminary findings suggest that susceptibility genes differ between IBD patients in Asia and the West. We aimed to evaluate diseasepredisposing genes in Asian IBD patients. METHODS: A systematic review and meta-analysis were performed of published studies from 1950 to 2010 using keyword searches in MEDLINE, EMBASE, EBM Reviews and BIOSIS Previews. RESULTS: 477 abstracts were identified and data extracted from 103 studies, comprising 17,976 IBD patients and 27,350 age- and sex-matched controls. Major nucleotide oligomerization domain (NOD)-2 variants in Western Crohn's disease (CD) patients were not associated with CD in Han Chinese, Japanese, South Korean, Indian and Malaysian populations. New NOD2 mutations were, however, associated with CD in Malaysians (JW1 mutation), Han Chinese and Indians (P268S). Autophagyrelated protein16-liked 1(ATG16L1) was not associated with CD in East Asians (OR 0.97; 95% CI 0.84-1.13). Interleukin (IL)-23R was associated with CD in South Koreans (OR 1.8; 95% CI 1.16-2.82) and a single nucleotide polymorphism in IL-23R, Gly149Arg, was protective of CD in Han Chinese (OR 0.3; 95% CI 0.15-0.60). Tumour necrosis factor (TNF)-SF15 polymorphisms were associated with CD (OR 2.68; 95% CI 1.86-3.86), while TNF-308 polymorphisms (OR 1.82; 95% CI 1.15-2.9), cytotoxic T lymphocyte antigen (CTLA)-4 (OR 2.75; 95% CI 1.22-6.22) and MICA allele (OR 2.41; 95% CI 1.89-3.07) were associated with ulcerative colitis (UC) in Asians. CONCLUSION: Genetic mutations of IBD in Asians differ from Caucasians. Novel genes identified in Asian IBD patients provide an opportunity to explore new disease-associated mechanisms in this population of rising incidence. Table 1: Major Findings of IBD Susceptibility Genes in Asia
Sa1278 New Genetic Associations Detected in an Exome-Wide Association Study for Toxicity Related to Thiopurine Treatments in Inflammatory Bowel Disease Maria Chaparro, William Zabala-Fernandez, Manuel Barreiro-De Acosta, Julian Panes, Maria Esteve, Montserrat Andreu, Esther Garcia-Planella, Eugeni Domènech, Ana Echarri, Daniel Carpio, Raquel Cruz, Francisco Barros, Javier P. Gisbert Background: Thiopurines are widely used to treat inflammatory bowel disease (IBD) patients but its benefits are limited by toxicity, which occurs in up to 15-30% of the patients. Several factors have been implicated in determining this adverse affects, mainly individual differences in formation of active metabolites, at least partly caused by genetic variation in the genes encoding thiopurine metabolism enzymes as TPMT. Aim: To conduct a two-stage exomewide association study to identify new genes involved in the rising of adverse effects after thiopurine treatment. Methods: 20,000 codificant single-nucleotide polymorphisms (cSNPs) in 10,000 genes were performed in a Galician (EIGA) cohort of 223 individuals diagnosed with IBD and treated with 2-2.5 mg/kg/day of azathioprine or 1-1.5 mg/kg/day of mercaptopuine, where 76 developed adverse effects versus 157 individuals displaying no side effects, a mean of 18 months after starting treatment. A second stage study that included an independent ENEIDA cohort of 344 individuals with IBD and the same treatment (85 individuals with adverse effects and 259 without side effects) was performed, genotyping by a MALDI-TOF methodology 60 cSNPs identified in the first stage with p<0.001. Results: Two SNPs in two genes showed a significant association in the combined analysis (Cochran Mantel Haenszel test): rs2228043 (p-value combined=9.59 x 10(-5); OR (95%CI)=3.74 (1.86-7.52) and rs1800124 (P-value combined=7.24 x 10(-5); OR (95%CI)=5.51 (2.1214.30). rs2228043 is in the exon 10 of the interleukin 6 signal transducer (gp130, oncostatin M receptor or IL6ST) gene, and was associated with risk of leucopenia. rs1800124 is in the exon 11 of excision repair cross-complementing rodent repair deficiency, complementation group 4 (ERCC4) gene, and was associated with pancreatitis. Conclusions: An exome-wide association study identified two new associations outside thiopurine metabolism pathways. Genetic variants in ILST and ERCC4 genes were associated with leucopenia and pancreatitis in patients treated with thiopurines. These findings might help to understand the biological reasons behind thiopurine toxicity, although they should be validated in larger and more diverse cohorts
NS: not studied + Associated - Not associated
S-271
AGA Abstracts
AGA Abstracts
1.97x10-7, OR=1.77). An additional three SNPs within this region are also found to be associated with nominal significance (p<10-5); and (2) at a second region on chr.4, ~37 Mb away, with the combined ASCA, I2, CBir1 and Ompc Z-score (rs2995965 plinear= 1.35x10-9, β=0.82; rs1863284 plinear=1.71x10-7, β=0.85; rs2911920 plinear=6.29x10-6, β=0.61). RELL1, a homologue of RELT the TNF receptor that induces epithelial cell apoptosis is located at this locus. Conclusions: These observations suggest that these two loci contribute to the phenotypic difference of UC patients, one for UC severity as typified by ANCA level, the other for the expression of antibodies more characteristic of CD. Studies to assess the phenotypic differences tagged by these SNPs within the UC population are in progress.