Lack of association of vitamin D receptor gene 3'-haplotypes with psoriasis in Croatian patients.

Cis-acting regulatory variants in biologically relevant pathways and target tissues are a common source of phenotypic variations and individual disease susceptibility. In the skin, vitamin D receptor (VDR) is a master regulator of epidermal barrier function, inflammation, stem cell proliferation and microbial defense; therefore, we tested whether VDR 3'-regulatory haplotypes, a portion of which affect VDR transcriptional efficiency, allelic symmetry and mRNA turnover, were associated with psoriasis vulgaris. For this purpose, three VDR tag polymorphisms that capture most of the variability of the VDR 3'-regulatory element (rs1544410, rs7975232 and rs731236) were genotyped by the polymerase chain reaction restriction fragment length polymorphism method in 180 Caucasian patients with chronic plaque psoriasis and 366 ethnically matched, healthy controls of the Croatian origin. We found no evidence of association for any of the selected polymorphisms. Similarly, none of the 3'-VDR restriction haplotypes were associated with the risk for development of psoriasis in Croatian patients. These results show that neither VDR 3'-restriction polymorphisms nor common 3'-regulatory haplotypes contribute to psoriasis risk in the Croatian population.