Association between vitamin D receptor gene polymorphisms and pulmonary tuberculosis in a Mexican population.

BACKGROUND AND AIMS: The impact of host genetic variation in susceptibility of tuberculosis is well documented. The vitamin D receptor gene (VDR) is a transacting transcription factor which mediates innate immune response by enhancing the expression of several antimicrobial peptides, including cathelicidin. An association between VDR polymorphisms with tuberculosis (TB) has been investigated in different ethnic groups; however there are contradictions and inconsistencies in the results. The aim of this study was to evaluate the association between polymorphisms of functional VDR with the susceptibility to pulmonary tuberculosis in a Mexican population.

METHODS: A case-control study was performed in, 257 patients with pulmonary tuberculosis and 457 healthy controls recruited from: family medicine clinics of the Mexican Social Security Institute. The VDR gene polymorphisms Fok I (rs 2228570), BsmI (rs1544410), ApaI (rs7975232) and TaqI (rs731236) were genotyped by TaqMan assays. Statistical analysis was performed using: Epi Info V-7 and SNP Stats software.

RESULTS: No statistically significant associations were observed in genotype and haplotype distribution between BsmI, ApaI and TaqI polymorphisms and disease susceptibility. The CC genotype for the VDR gene FokI was significantly more frequent in patients than in controls (29.6% versus 17.5%, OR=1.97; 95% CI=1.37-2.8, PC =0.0004). Moreover, TT genotype was decreased in patients as compared to the control group (24.1% versus 34.8%, OR=0.59; 95% CI=0.42-0.84, PC =0.004).

CONCLUSION: To our best knowledge, this is the first case-control study that finds an association between CC genotype of FokI SNP in the VDR gene with pulmonary tuberculosis in Mexican patients. However more validation studies should be performed to prove our conclusions.