Polymorphisms of vitamin D receptor gene in the population of eastern Croatia with psoriasis vulgaris and diabetes mellitus

The aim of this study was to evaluate the possible association between polymorphisms in the Vitamin D receptor gene (VDR gene) and tendency for development of psoriasis vulgaris and diabetes mellitus in the population of Slavonia, which is a region in the Eastern Croatia. In order to conduct the mentioned evaluation the restriction fragment length polymorphisms (ApaI, BsmI and TaqI) in the Vitamin D receptor gene were researched in three groups of patients: patients suffering only from psoriasis vulgaris, patients suffering only from diabetes mellitus, and patients suffering at the same time from both diseases. Four most common genotypes were found in all standardized control patients: triple heterozygotes BbAaTt (in 29.3% of the studied patients), bbAaTT (in 18.6% of the studied patients), bbaaTT (in 12.9% of the studied patients) and BbAATt (in 8.6% of the studied patients). Three most common VDR 3'-RFLP haplotypes determined in this study were: three-component baT, Bat and bAT haplotype. Results of the Hardy-Weinberg equilibrium showed presence of BsmI polymorphism genotype frequencies disequilibrium in the group of patients suffering from psoriasis and ApaI polymorphism in the group of patients suffering from both diseases. According to the same statistical test all conditions for TaqI polymorphism genotype frequency were fulfilled in all groups of studied patients. There was no significant difference in distribution of BsmI, ApaI or TaqI polymorphism genotype frequencies between control patients and any of the subgroup of studied patients. In studied population none of analysed polymorphisms individually was associated with the risk of development of psoriasis, diabetes or combined phenotype.