Meta‐analysis: polymorphisms in TNF‐α gene promoter and Crohn’s disease

Abstract

SUMMARY BackgroundTumour necrosis factor alpha (TNF-a) is involved in the pathogenesis of Crohn's disease (CD). However, results on the association between the polymorphisms in TNF-a promoter and the risk of CD are inconsistent.

TNF-alpha gene polymorphisms in Iranian Azari Turkish patients with inflammatory bowel diseases

“…[19] In 2003, Gonzalez et al ., showed that the TNFα-308A polymorphism was associated with enhanced TNFα production and an increased risk for susceptibility to arthritis in CD patients. [20] In the present study, we determined the allelic and genotypic distribution of two SNPs (at positions -308 and -1031) in the TNFα gene among IBD patients and healthy controls in the Iranian Azari Turkish ethnic group. In our study, we found a nonstatistically significant reduction of -308A and -1031C allele frequencies in IBD patients compared with controls.…”

“…The polymorphic -1031T > C site may either bind to unknown regulatory elements or alter the secondary structure of DNA to affect accession of cis-acting transcription factors to the promoter/enhancer region of the TNFα gene. [20] Previous studies regarding the association of TNFα gene polymorphism and IBD susceptibility have reported conflicting results. Depending on studied populations, some reports show positive association and the others failed to show any significant association with TNFα gene polymorphisms and IBD.…”

“…[25] The results of our study are consistent with some previous reports. [2026] In the study by Zipperlen et al ., no association between TNFα promoter polymorphisms and CD was observed. [21] Conversely, in a study carried out by Balding and colleagues, there was a significant variation in TNFα-308 polymorphism genotype frequency when comparing the control group with the UC group.…”

Inflammatory Bowel Disease: The Association of Inflammatory Cytokine Gene Polymorphisms

“…Although the frequency of allele G was reported to be slightly higher in Iranian Azeri Turkish IBD patients, it did not reach statistical significance [110]. Further, no association of TNF-α(-308G/A) polymorphism with IBD susceptibility was found in Australian [82], Brazilian [60,130], Canadian [100], Chinese [106,131], Czech [132], French [133], Indian [108], Korean [115], Newfoundland [27], Spanish [126], and Turkish [120] populations. The reason for these differences in the TNF-α genetic associations with IBD etiology might be the variations in sample size, genotyping methods, and/or ethnicity itself as frequencies of alleles and genotypes of TNF-α (-308G/A) also vary in different ethnic healthy populations worldwide [39] ( Table 3).…”

Population features of prevalence and clinical-diagnostic role of NOD2 gene polymorphisms associated with Crohn’s disease

“…Известно более 140 генов, нуклеотидные полиморфизмы которых прямо или косвенно связаны с различными звеньями патогенеза БК. В частности, полиморфизмы генов NOD2, TLR2, TLR4, TLR9, CARD9 ассоциированы с нарушениями врожденного иммунитета [5][6][7][8][9], полиморфизмы генов TNF-α, TNFRSF1A, TNFRSF1B, IL-10, IL-4, MST1, IL-18RAP, TGFB1 -с нарушениями вторичного иммунного ответа [9][10][11][12][13][14], полиморфизмы генов IL-23R, STAT3, JAK2, IL-12B -с нарушениями дифференцировки Th17-лимфоцитов [15][16][17][18], полиморфизмы генов DEFB1, TFF1-3, MUC2, MUC3, MUC4 -с нарушениями слизистого и эпителиального барьеров кишечника [19][20][21][22], полиморфизмы генов ATG16L1, IRGM, CALCOCO2/NDP52 -с нарушениями аутофагии [23,24].…”