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Alain Bitton

Publications and source records attributed to Alain Bitton.

17 recordsLinked to original sources
PubMed2006

A genome-wide association study identifies IL23R as an inflammatory bowel disease gene.

The inflammatory bowel diseases Crohn's disease and ulcerative colitis are common, chronic disorders that cause abdominal pain, diarrhea, and gastrointestinal bleeding. To identify genetic factors that might contribute to these disorders, we performed a genome-wide association study. We found a highly significant association between Crohn's disease and the IL23R gene on chromosome 1p31, which encodes a subunit of the receptor for the proinflammatory cytokine interleukin-23. An uncommon coding variant (rs11209026, c.1142G>A, p.Arg381Gln) confers strong protection against Crohn's disease, and additional noncoding IL23R variants are independently associated. Replication studies confirmed IL23R associations in independent cohorts of patients with Crohn's disease or ulcerative colitis. These results and previous studies on the proinflammatory role of IL-23 prioritize this signaling pathway as a therapeutic target in inflammatory bowel disease.

Alleles↗
PubMed2006

Genetic variation in myosin IXB is associated with ulcerative colitis.

BACKGROUND & AIMS: Common germline genetic variation in the 3' region of myosin IXB (MYO9B) has been associated recently with susceptibility to celiac disease, with a hypothesis that MYO9B variants might influence intestinal permeability. These findings suggested the current study investigating a possible further role for MYO9B variation in inflammatory bowel disease. METHODS: Eight single-nucleotide polymorphisms (SNPs) were selected to tag common haplotypes from the 35-kb 3' region of MYO9B. These included the strongest celiac disease-associated variants reported in a Dutch cohort. These SNPs were studied in 3 independently collected and genotyped case-control cohorts of European descent (UK, Dutch, and Canadian/Italian), comprising in total 2717 inflammatory bowel disease patients (1197 with Crohn's disease, 1520 with ulcerative colitis) and 4440 controls. RESULTS: Common variation in MYO9B was associated with susceptibility to inflammatory bowel disease in all 3 cohorts examined (most associated SNP, rs1545620; meta-analysis P = 1.9 x 10(-6); odds ratio, 1.2), with the same alleles showing association as reported for celiac disease. CONCLUSIONS: MYO9B genetic variants predispose to inflammatory bowel disease. Interestingly, rs1545620 is a nonsynonymous variant leading to an amino acid change (Ala1011Ser) in the third calmodulin binding IQ domain of MYO9B. Unlike previous variants (in other genes) reported to predispose to inflammatory bowel disease, the association at MYO9B was considerably stronger with ulcerative colitis, although weaker association with Crohn's disease also was observed. These data imply shared causal mechanisms underlying intestinal inflammatory diseases.

Adolescent↗
PubMed2006

Evaluating the role of the 620W allele of protein tyrosine phosphatase PTPN22 in Crohn's disease and multiple sclerosis.

The 620W allele of PTPN22 has been associated with susceptibility to several different forms of chronic inflammatory disease, including Type 1 diabetes (T1D), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and autoimmune thyroiditis (AIT). We set out to explore its possible role in two other inflammatory diseases: multiple sclerosis (MS) and Crohn's disease (CD). In our cohort of 496 MS trios from the United Kingdom, we observed reduced transmission of the PTPN22 620W allele. The CD sample consisted of 169 trios as well as 249 cases of CD with their 207 matched control subjects collected in the province of Québec, Canada; there was also no evidence of association between the PTPN22 620W allele and susceptibility for CD. Pooled analyses combining our data with published data assessed a total of 1496 cases of MS and 1019 cases of CD but demonstrated no evidence of association with either disease. Given the modest odds ratios of known risk alleles for inflammatory diseases, these analyses do not exclude a role for the PTPN22 allele in susceptibility to CD or MS, but they do suggest that such a putative role would probably be more modest than that reported so far in T1D, RA, SLE, and AIT.

Alleles↗
PubMed2006

Inflammatory bowel disease characteristics among African Americans, Hispanics, and non-Hispanic Whites: characterization of a large North American cohort.

OBJECTIVES: Inflammatory bowel disease (IBD), comprising primarily of Crohn's disease (CD) and ulcerative colitis (UC), is increasingly prevalent in racial and ethnic minorities. This study was undertaken to characterize racial differences in disease phenotype in a predominantly adult population. METHODS: Phenotype data on 830 non-Hispanic white, 127 non-Hispanic African American, and 169 Hispanic IBD patients, recruited from six academic centers, were abstracted from medical records and compiled in the NIDDK-IBD Genetics Consortium repository. We characterized racial differences in family history, disease location and behavior, surgical history, and extraintestinal manifestations (EIMs) using standardized definitions. RESULTS: African American CD patients were more likely than whites to develop esophagogastroduodenal CD (OR = 2.8; 95% CI: 1.4-5.5), colorectal disease (OR = 1.9; 95% CI: 1.1-3.4), perianal disease (OR = 1.7; 95% CI: 1.03-2.8), but less likely to have ileal involvement (OR = 0.55; 95% CI: 0.32-0.96). They were also at higher risk for uveitis (OR = 5.5; 95% CI: 2.3-13.0) and sacroiliitis (OR = 4.0; 95% CI: 1.55-10.1). Hispanics had higher prevalence of perianal CD (OR = 2.9; 95% CI: 1.8-4.6) and erythema nodosum (3.3; 95% CI: 1.7-6.4). Among UC patients, Hispanics had more proximal disease extent. Both African American and Hispanic CD patients, but not UC patients, had lower prevalences of family history of IBD than their white counterparts. CONCLUSIONS: There are racial differences in IBD family history, disease location, and EIMs that may reflect underlying genetic variations and have important implications for diagnosis and management of disease. These findings underscore the need for further studies in minority populations.

Adult↗
PubMed2006

Dermatomyositis associated with celiac disease: response to a gluten-free diet.

The association between dermatomyositis and celiac disease in children has been well documented. In the adult population, however, the association has not been clearly established. A rare case of concomitant dermatomyositis and celiac disease in a 40-year-old woman is presented. After having been diagnosed with dermatomyositis and iron deficiency anemia, this patient was referred to the gastroenterology clinic to exclude a gastrointestinal malignancy. Blood tests revealed various vitamin deficiencies consistent with malabsorption. The results of gastroscopy with duodenal biopsy were consistent with celiac disease. After she was put on a strict gluten-free diet, both nutritional deficiencies and the dermatomyositis resolved. The patient's human leukocyte antigen haplotype study was positive for DR3 and DQ2, which have been shown to be associated with both juvenile dermatomyositis and celiac disease. It is suggested that patients with newly diagnosed dermatomyositis be investigated for concomitant celiac disease even in the absence of gastrointestinal symptoms.

Adult↗
PubMed2005

Association of DLG5 R30Q variant with inflammatory bowel disease.

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the gastrointestinal system known as the inflammatory bowel diseases (IBD). Recently, Stoll and colleagues reported a novel finding of genetic variation in the DLG5 gene that is associated with IBD (CD and UC combined). We present here a study of the genetic variation described in that report in two well-powered, independent case-control cohorts and one family-based collection, and confirm the proposed association between IBD and the R30Q variant of DLG5 in two of the three studies. We are, however, unable to replicate the other proposed association to the common haplotype described in Stoll et al and suggest that this other finding could conceivably have been partially a statistical fluctuation and partially a result of LD with the replicated R30Q association. This study provides support for the hypothesis that DLG5 constitutes a true IBD risk factor of modest effect.

Case-Control Studies↗
PubMed2005

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

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

Adenine↗
PubMed2004

Newer disease-modifying antirheumatic drugs and the risk of serious hepatic adverse events in patients with rheumatoid arthritis.

BACKGROUND: Spontaneous cases of hepatic adverse events have been reported in patients with rheumatoid arthritis who were being treated with leflunomide, one of the newer disease-modifying antirheumatic drugs (DMARDs). We assessed the risk of hepatic events associated with the use of leflunomide and other DMARDs. METHODS: Two cohorts comprising 41,885 patients with rheumatoid arthritis who had been dispensed a DMARD between September 1, 1998, and December 31, 2001, were formed using claims databases. Follow-up was from the first dispensing date to the occurrence of a serious or nonserious hepatic event. A nested case-control approach was used to estimate adjusted rate ratios of hepatic events associated with DMARDs dispensed during the prior year, as compared with methotrexate monotherapy. RESULTS: There were 25 cases of serious hepatic events (rate, 4.9 per 10,000 per year) and 411 nonserious hepatic events (rate, 80.0 per 10,000 per year). There was no increase in the rate of serious hepatic events with either leflunomide (rate ratio [RR] = 0.9; 95% confidence interval [CI]: 0.2 to 4.9) or traditional DMARDs (RR = 2.3; 95% CI: 0.8 to 6.5). However, the rate was increased with biologic DMARDs (RR = 5.5; 95% CI: 1.2 to 24.6). The rate of nonserious hepatic events was also increased with biologic DMARDs (RR = 1.5; 95% CI: 1.0 to 2.3), but not with leflunomide (RR = 0.9; 95% CI: 0.7 to 1.3) and traditional DMARDs (RR = 1.1; 95% CI: 0.8 to 1.4). CONCLUSIONS: We found no evidence of an excess risk of serious or nonserious hepatic events with the use of leflunomide as compared with methotrexate. Still, the increased risk observed with the new biologic DMARDs should be investigated further.

Adult↗
PubMed2003

Patient nonadherence to medication in inflammatory bowel disease.

OBJECTIVE: The aim of this study was to identify determinants of nonadherence to medication in outpatients with established inflammatory bowel disease (IBD). METHODS: Ten gastroenterologists and 153 of their IBD patients participated in this prospective study. Demographic, clinical, and psychosocial characteristics, as well as patient-physician discordance, were assessed at an office visit. Nonadherence to medication was assessed 2 wk later. Separate generalized estimating equations were used to identify determinants of nonadherence. RESULTS: Physicians averaged 47.9 yr in age (range 30.1-57.5 yr), and 90% were male. Patients averaged 37.0 yr (SD = 15.1), and 87 (56.9%) were female. In all, 63 patients (41.2%) were nonadherent to medication; of these, 51 (81.0%) indicated unintentional nonadherence, 23 (36.5%) intentional nonadherence, and 11 (17.5%) both. Overall nonadherence was predicted by disease activity (OR = 0.55, p = 0.0022), new patient status (OR = 2.14, p = 0.0394), disease duration (OR = 0.50, p = 0.0001), and scheduling a follow-up appointment (OR = 0.30, p = 0.0059), whereas higher discordance on well-being was predictive only in psychologically nondistressed patients (p = 0.0026 for interaction). Unintentional nonadherence was predicted by age (OR = 0.97, p = 0.0072), new patient status (OR = 2.80, p = 0239), and higher discordance on well-being in psychologically nondistressed patients (p = 0.0504). Intentional nonadherence was predicted by disease duration (OR = 0.55, p = 0032), scheduling a follow-up appointment (OR = 0.12, p = 0.0001), certainty that medication would be helpful (OR = 0.99, p = 0.0409), and total patient-physician discordance (OR = 1.59, p =.0120). CONCLUSIONS: These findings suggest that the therapeutic relationship, as well as individual clinical and psychosocial characteristics, influence adherence to medication.

Adult↗
PubMed2003

Psychosocial determinants of relapse in ulcerative colitis: a longitudinal study.

OBJECTIVES: To determine the association between psychosocial characteristics and time to relapse in patients with inactive ulcerative colitis. METHODS: Sixty patients with clinically and endoscopically inactive ulcerative colitis were followed for 1 yr, or less if they relapsed. Demographic, psychosocial, and clinical data were obtained. Stressful life events (Psychiatric Epidemiology Research Interview Life Events Scale), psychological distress (Symptom Checklist-90R), and perceived stress (Perceived Stress Scale) were recorded monthly by self-report. Multivariate time-dependent Cox regression was used to identify the independent determinants of earlier time to clinical relapse. RESULTS: The patients' mean age was 39 yr (SD = 9.4), 37 (62%) were female, and 22 (37%) relapsed during the 1-yr follow-up. Univariate Cox regression indicated a weak association between number of stressful events in the preceding month and time to relapse (p = 0.09). This association strengthened in multivariate analysis (p = 0.02, hazard ratio = 1.26 per event, 95% CI = 1.04-1.53) after adjustment for significant covariates. CONCLUSIONS: After controlling for demographic and clinical variables, more recent stressful events were associated with earlier time to relapse. These findings, which support a biopsychosocial model of disease, might help clinicians identify patients who might benefit from more intensive maintenance medical therapy and behavioral medicine interventions to reduce stress and improve coping.

Adult↗
PubMed2002

CARD15 genetic variation in a Quebec population: prevalence, genotype-phenotype relationship, and haplotype structure.

The caspase recruitment domain gene (CARD15) was recently identified as the underlying gene associated with the IBD1 locus that confers susceptibility to Crohn disease (CD). CARD15 is related to the NOD1/Apaf-1 family of apoptosis regulators, and three sequence variants (Arg702Trp, Gly908Arg, and Leu1007fsinsC) in the gene were demonstrated to be associated with CD. We collected a cohort of 231 patients with CD and 71 healthy control individuals from the Canadian province of Quebec, to determine the prevalence of these sequence variants in an independent population. Clinical records of all patients were systematically reviewed, and detailed phenotypic information was obtained. All patient DNA samples were genotyped for the three variants, thus enabling an analysis of genotype-phenotype correlations. In this cohort, 45.0% of patients with CD carried at least one variant in the CARD15 gene, compared with 9.0% of control individuals (P<10-7). Allele frequencies of Arg702Trp, Gly908Arg, and Leu1007fsinsC were 12.9%, 5.2%, and 10.3% in patients with CD, compared with 4.2%, 0.7%, and 0.7% in control individuals, respectively. Importantly, CARD15 mutants were seen with equal frequency in patients with familial and sporadic CD. Analysis of the relationship between genotype and phenotype convincingly demonstrates that CARD15 variants are significantly associated with ileal disease involvement, as opposed to strictly colonic disease (P<.001). Moreover, we were able to determine the haplotype structure surrounding this disease gene by genotyping 45 single-nucleotide polymorphisms (SNPs) in a 177-kb region that contained the CARD15 gene. This structure helps clarify the history of these causal mutations. Finally, this analysis shows that CARD15 involvement with CD is detectable by use of publicly available SNPs alone.

Adult↗
PubMed2002

The atypical colitides.

Collagenous and lymphocytic colitis are atypical colitides that should be considered in elderly patients with unexplained diarrhea. The lack of natural history data and apparent underreporting of these disorders have made the determination of true incidence difficult. Better insight into the pathogenesis and heightened awareness of these conditions will lead to earlier diagnosis and more effective treatment.

Aged↗
PubMed2002

The role of endoscopy in the evaluation of pouches and ostomies.

Patients with ileal pouches and ostomies present with management issues that are challenging to the clinician. Endoscopy plays a significant role in diagnosing and guiding therapy in such patients. Unfortunately, there are very few prospective studies that evaluates endoscopy in these situations. Nevertheless, it is clear that endoscopy remains a powerful tool that is important for diagnosis and therapy of complications unique to these surgical procedures. It seems prudent to advocate endoscopic cancer surveillance for patients with pouches and ostomies; however, it remains to be seen whether these efforts will ultimately have an impact on long-term patient morbidity and mortality.

Colonic Pouches↗
PubMed2002

Combined budesonide and antibiotic therapy for active Crohn's disease: a randomized controlled trial.

BACKGROUND & AIMS: Although antibiotics are frequently used to treat Crohn's disease, this practice is not supported by strong evidence from randomized trials. METHODS: We conducted a double-blind multicenter study of patients with active Crohn's disease of the ileum, right colon, or both. Patients were randomized to receive oral ciprofloxacin and metronidazole, both 500 mg twice daily, or placebo for 8 weeks. All patients received oral budesonide 9 mg once daily. The primary efficacy measure was the proportion of patients in remission at week 8. RESULTS: Of the 134 patients who were randomized, 130 were evaluated for efficacy; 66 received placebo, and 64 received antibiotics. At week 8, 21 patients (33%) assigned to antibiotics were in remission as compared with 25 patients (38%) in the placebo group (P = 0.55; absolute difference, -5%; 95% confidence interval, -21% to 11%). An interaction (P = 0.025) between treatment allocation and disease location on treatment response was identified. Among patients with disease of the colon, 9 of 17 (53%) were in remission after treatment with antibiotics, compared with 4 of 16 (25%) of those who received placebo (P = 0.10). Discontinuation of therapy because of adverse events occurred in 13 of 66 (20%) patients treated with antibiotics, compared with 0 of 68 in the group who received placebo (P < 0.001). CONCLUSIONS: In patients with active Crohn's disease of the ileum, the addition of ciprofloxacin and metronidazole to budesonide is an ineffective intervention, but this antibiotic combination may improve outcome when there is involvement of the colon.

Administration, Oral↗
PubMed2002

Psychosocial correlates of patient-physician discordance in inflammatory bowel disease.

OBJECTIVE: The aim of this study was to identify the independent psychosocial correlates of patient-physician discordance in adult outpatients with inflammatory bowel disease. METHODS: This cross-sectional study was conducted in three university-affiliated tertiary care settings. Psychological distress, social support, perceived stress, and negative life events were assessed, as were demographic, lifestyle, and clinical characteristics. Patient-physician discordance was assessed with 10-item questionnaires. RESULTS: Ten gastroenterologists and 200 of their patients participated. Patients and their physicians disagreed most on discussion of personal issues. Patients with Crohn's disease had statistically significantly higher discordance on disease activity and physical limitation, as well as higher average overall discordance scores than patients with ulcerative colitis. Mean discordance levels were similar across different physicians. Higher psychological distress and more perceived stress were independently associated with higher discordance after controlling for Crohn's disease, active disease, being with the treating physician for less than 1 yr, and recommendation for further medical investigation. Psychological distress was the most important correlate of overall discordance. CONCLUSIONS: Increased physician awareness that psychologically distressed patients have difficulty processing of clinically relevant information may lead to improved doctor-patient communication during an office visit.

Adult↗