P649. Relationship between clinical characteristics and vitamin D receptor polymorphisms in Crohn's disease
O. Terjek1, A.A. Csontos1, K. Lorinczy1, A. Bors2, A. Torday2, P.L. Lakatos3, P. Miheller1, 1Semmelweis University, 2nd Department of Medicine, Budapest, Hungary, 2Hungarian National Blood Transfusion Service, Department of Molecular Diagnostics, Budapest, Hungary, 3Semmelweis University, 1st Department of Medicine, Budapest, Hungary
Numerous single nucleotide polymorphisms (SNP) have been identified in the vitamin D receptor (VDR). According to previous studies, there was a significant increase in Crohn's disease (CD) risk for European patients carrying TaqI tt genotype and a significant decrease in CD risk for all carriers of the Apal “a” allele. Relation of the existence of one or more of these SNPs has been not evaluated regarding the clinical characteristics of CD patients. The aim of our study was to investigate the frequencies of VDR polymorphisms among our IBD patients and to evaluate whether these mutations have any impact to the clinical characteristics of IBD.
We included 609 IBD patients (359 CD, 250 UC) into our study. Cdx2, FokI, ApaI and TaqI SNPs were determined by polymerase chain reaction. Detailed clinical phenotypes were determined by reviewing the medical charts.
Both homozygous and heterozygous TaqI polymorphisms were more frequent in UC than CD (47.9% vs. 41.6% and 16.4% vs. 12.4%, p < 0.05, respectively). The wild type allele was more rare in CD (OR = 0.65, 95% CI, 0.468–0.904). TaqI mutation was observed to be more frequent in case of early (<40 years of age) disease CD onset (66.0% vs 48.5%), however the difference was not significant (p = 0.056). We observed two allele variations which were observed to be protective IBD associated arthritis. TaqI variation and ApaI homozygous variation were observed to be more frequent in patients without arthritis (59.1% vs. 41.5%, p = 0.02, and 76.6% vs. 23.4%, p < 0.01; respectively). Need for azathioprine therapy was showed to be less frequent in patients having TaqI polymorphism (OR: 0.485, 95% CI, 0.252–0.934). No other relationship was observed between the clinical characteristics of IBD and the further explored SNPs or their combination.
There are inconsistent data regarding the significance of VDR polymorphisms in the pathogenesis of IBD. However, our data suggests that these variations may affect the clinical characteristics of IBD. The most remarkable relationship was observed regarding protective effect of variant alleles of TaqI and ApaI in CD associated arthritis.