Distribution of common CARD15 variants in patients with sporadic Crohn's disease: cases from Turkey

Bactericidal permeability increasing protein gene polymorphism is associated with inflammatory bowel diseases in the Turkish population

BACKGROUND/AIMS

Inflammatory bowel disease, a chronic inflammatory disease with unknown etiology, affects the small and large bowel at different levels. It is increasingly considered that innate immune system may have a central position in the pathogenesis of the disease. As a part of the innate immune system, bactericidal permeability increasing protein has an important role in the recognition and neutralization of gram-negative bacteria. The aim of our study was to investigate the involvement of bactericidal permeability increasing protein gene polymorphism (bactericidal permeability increasing protein Lys216Glu) in inflammatory bowel disease in a large group of Turkish patients.

PATIENTS AND METHODS

The present study included 528 inflammatory bowel disease patients, 224 with Crohn's disease and 304 with ulcerative colitis, and 339 healthy controls.

RESULTS

Bactericidal permeability increasing protein Lys216Glu polymorphism was found to be associated with both Crohn's disease and ulcerative colitis (P = 0.0001). The frequency of the Glu/Glu genotype was significantly lower in patients using steroids and in those with steroid dependence (P = 0.012, OR, 0.80; 95% confidence interval [CI]: 0.68-0.94; P = 0.0286, OR, 0.75; 95% CI: 0.66-0.86, respectively). There was no other association between bactericidal permeability increasing protein gene polymorphism and phenotypes of inflammatory bowel disease.

CONCLUSIONS

Bactericidal permeability increasing protein Lys216Glu polymorphism is associated with both Crohn's disease and ulcerative colitis. This is the first study reporting the association of bactericidal permeability increasing protein gene polymorphism with steroid use and dependence in Crohn's disease.

Association of the MEFV gene variations with inflammatory bowel disease in Turkey

BACKGROUND

Association of NOD2 (CARD15) gene mutations with inflammatory bowel diseases (IBD) is well known. We herein aimed to investigate the role of familial Mediterranean fever-associated MEFV variations in IBD patients as additional regional-specific risk factor.

STUDY

One hundred thirty-seven (78 female, 56.9%) IBD patients [62 Crohn's disease (CD), 75 ulcerative colitis (UC)] were enrolled into the study. The diagnosis of all patients was confirmed by colonoscopy, histopathology, and the clinical findings. One hundred one healthy donors' samples were used as healthy controls. All patients were genotyped for the most common E148Q, M608I, M694V, and V726A variations of the MEFV and R702W, G908R, and 1007fs of the NOD2.

RESULTS

The overall MEFV variation frequency was found to be higher in the IBD (25.5%) patients (28% in UC, 22.6% in CD) compared with controls (9.9%, P=0.006). This association was stronger with the penetrant exon 10 variations (M694V, M680I, V726A; odds ratio =4.5, P=0.001). Contribution of M694V was higher compared with the other variations (14.5% in CD, 17.3% in UC and 3% in controls, odds ratio =6.039, 95% confidence intervals, 1.7-20.7, P=0.002). The overall frequency of 3 NOD2 variants in the IBD group was not different from that of controls.

CONCLUSIONS

The results of this study suggest that the MEFV variations may be an additional susceptibility factor for IBD in certain parts of the world where the carrier rate is high, and the genetic background of the IBD patients may show regional changes.

Genetics of inflammatory bowel disease in Asia: systematic review and meta-analysis

BACKGROUND

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 disease-predisposing 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

In all, 477 abstracts were identified and data extracted from 93 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), Han Chinese, and Indians (P268S). Autophagy-related protein 16-linked 1 (ATG16L1) was not associated with CD in East Asians (odds ratio [OR] 0.97; 95% confidence interval [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). Tumor necrosis factor (TNF) superfamily gene-15 (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 in Asians.

CONCLUSIONS

Genetic mutations of IBD in Asians differ from Caucasians. New mutations and susceptibility genes identified in Asian IBD patients provide an opportunity to explore new disease-associated mechanisms in this population of rising incidence.

Association between bactericidal/permeability increasing protein (BPI) gene polymorphism (Lys216Glu) and inflammatory bowel disease

BACKGROUND

Increasing evidence suggests that innate immune system may have a key role in the pathogenesis of the inflammatory bowel disease (IBD). Bactericidal/permeability increasing protein (BPI) has an important role in the recognition and neutralization of gram-negative bacteria by host innate immune system. The polymorphism on BPI gene called Lys216Glu is on the suspected list of IBD pathogenesis.

METHODS

We studied the Lys216Glu polymorphism on BPI gene, in a Turkish IBD patient population. A total of 238 IBD patients; 116 Crohn's disease (CD) and 122 ulcerative colitis (UC), besides 197 healthy controls were included in this study.

RESULTS

The Glu/Glu genotype and allele frequencies were found to be statistically higher compared to healthy control group not only in CD patients [P: 0.03, OR: 1.87 (CI 95% 1.02-3.42) and P: 0.00001 (OR: 2.07 CI 95% 1.47-2.91) respectively] but also in UC patients [P: 0.0002, OR: 2.71 (CI 95% 1.53-4.80) and P: 0.00002 (OR: 2.71 CI 95% 1.53-4.80) respectively].

CONCLUSIONS

BPI polymorphism (Lys216Glu) is associated both to CD and UC. Our findings differ from the two Western European studies; one without any association and the other indicating an association only with CD. Our study is the first one reporting a novel association between BPI gene mutation (Lys216Glu) and UC.

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.

New global map of Crohn's disease: Genetic, environmental, and socioeconomic correlations

Seventy-five years after the initial characterization of Crohn's disease (CD), much remains obscure about its etiology. The authors sought to evaluate the incidence trends of the last 25 years worldwide, and the existence of potential correlations with genetic, environmental, and socioeconomic factors that could be etiologically implicated in the pathogenesis of CD. Relevant medical literature for individual countries on the incidence of CD, on the incidence of associated genetic mutations, and on the incidence of suggested etiologic infectious agents such as Mycobacterium avium paratuberculosis were retrieved from published medical literature, reports from relevant international congresses, and through official reports from national health authorities. Increasing trends have been observed almost worldwide, with a broad north-south gradient still prevailing in Europe. Distinct regions of New Zealand, Canada, Scotland, France, the Netherlands, and Scandinavia represent the highest incidence areas. Industrialized status and affluence are the common denominators between endemic areas, but are too broad as terms to strongly indicate any particular etiological role. The increasing trends observed in Asia still account for a low prevalence of the disease and may represent increased detection and diagnostic ability of local health systems. Genetic associations are variably reproduced worldwide, in a manner inconsistent with a strong etiologic relationship. Data on paratuberculosis incidence are scarce, and the existing ones are ambivalent regarding an even indirect correlation between CD and an infectious trigger.

Epidemiological evidence for Mycobacterium avium subspecies paratuberculosis as a cause of Crohn's disease

Mycobacterium avium subspecies paratuberculosis is the causative agent of Johne's disease, a chronic enteritis in ruminants including cattle, sheep, goats, and farmed deer. Recently, this bacterium has received an increasingly wide interest because of a rapidly growing body of scientific evidence which suggests that human infection with this microorganism may be causing some, and possibly all, cases of Crohn's disease. Recent studies have shown that a high percentage of people with Crohn's disease are infected with M. avium subsp. paratuberculosis; whether the association of this bacterium and Crohn's disease is causal or coincidental is not known. Crohn's disease is a gastrointestinal disease in humans with similar histopathological findings to those observed in the paucibacillary form of Johne's disease in cattle. The search for risk factors in Crohn's disease has been frustrating. However, epidemiologists have gathered enough information that points to an association between M. avium subsp. paratuberculosis and Crohn's disease. This paper reviews epidemiological models of disease causation, the major philosophical doctrines about causation, the established epidemiological criteria for causation, and the currently known epidemiological evidence of M. avium subsp. paratuberculosis as a possible cause of Crohn's disease.