Impact of vitamin D receptor gene variants on psoriasis vulgaris susceptibility and clinical phenotype in a Greek population.

Psoriasis vulgaris (PsV) is a complex immune-mediated disease with a polygenic component. Common variants in the vitamin D receptor (VDR) gene have been explored in the context of psoriasis, but findings remain inconsistent and data from the Greek population are scarce. Thus, the present study aimed to investigate the association of the VDR FokI (rs2228570), BsmI (rs1544410) and TaqI (rs731236) single-nucleotide polymorphisms (SNPs) with PsV susceptibility and clinical phenotype in a Caucasian Greek cohort. In this observational cross-sectional study, 203 patients with chronic plaque psoriasis and 812 age-, sex- and ethnically-matched controls of Greek origin were genotyped for the selected VDR SNPs using real-time PCR (melting curve analysis) and SNP-based statistical comparisons were performed. Case-control analyses exhibited a significant association between the BsmI variant and PsV susceptibility under the recessive and allelic models, with the A allele (A vs. G; OR: 0.765; 95% CI: 0.614-0.953; adjusted P=0.032) and AA genotype (AA vs. GA + GG; OR: 0.577; 95% CI: 0.386-0.861; adjusted P=0.028) conferring a protective effect. No impact on PsV risk was observed for FokI or TaqI. Intra-patient subgroup analyses based on clinical traits indicated phenotype-specific contributions: FokI was associated with early-onset and familial disease, TaqI with psoriatic arthritis and both BsmI and TaqI with nail involvement. To the best of our knowledge, this study provides the first evidence that VDR genetic variation may influence PsV susceptibility and clinical expression in the Greek population. The VDR locus could thus serve as a potential biomarker for tailored risk stratification and clinical profiling in PsV. Further large-scale studies integrating genotypic and phenotypic data, especially among Caucasians, are required to validate these findings.