The ApaI, TaqI and FokI vitamin D receptor (VDR) gene polymorphism are associated with risk of inflammatory bowel diseases (IBD)1. These genetic variants can also determine changes in vitamin D mechanisms of action and affect the clinical course of IBD2. In Brazil, there are a lack of data concerning VDR polymorphisms in IBD patients and its use as a predictor of poor prognosis. The aim of this study was to evaluate the association of VDR gene polymorphisms, vitamin D status and the poor prognostic factors in a multiracial IBD population.Methods:
A case control study recruited 107 patients with Crohn's disease (CD), 43 patients with ulcerative colitis (UC) and 81 control healthy subjects from a tertiary center in Rio de Janeiro. The VDR polymorphisms ApaI, (“Aa,” “aa”), TaqI (“Tt,” “tt”) e FokI (“Ff,” “ff”) were evaluated in IBD and non IBD groups. The genotyping was performed by polymerase chain reaction (PCR) in real time technique. Serum 25(OH)D was measured using chemiluminescence immunoassay. Demographic, clinical features and poor prognostic factors of IBD patients were obtained from the chart review.Results:
The genotype “aa” (ApaI) (49.5%) and “Tt” (TaqI) (50.5%) were more frequent in CD group. The distribution of polymorphisms was similar between UC and the control group. In CD group, the “a” allele carrier status of ApaI appeared to be a protective factor against the use of immunosuppressors (OR = 0.225; 95% CI, 0.071–0.712). The “t” allele carrier status of TaqI was protective factor against the use of steroids at the time of CD diagnosis (OR = 0.242; 95% CI, 0.065–0.901) but it was associated with the need of more than 2 steroids courses in UC group (OR = 4.19; 95% CI, 1.104–15.901) The 25(OH)D level was measured in 44 IBD patients, and low levels were detected only in 38.6% of cases. No association was observed between clinical features, VDR polymorphisms and vitamin D deficiency.Conclusions:
The ApaI and TaqI, but not FokI polymorphisms are associated with CD and a poor prognostic factors. Although the polymorphisms have not been associated with UC, the presence of TaqI polymorphism was associated with poor prognosis predictor in this group. No associations were detected between VDR polymorphisms and vitamin D deficiency in IBD groups.