The relationship between vitamin D receptor (VDR) genomic polymorphisms, disease activity, and functional ability in patients with psoriatic arthritis.

Introduction/objectives: Psoriatic arthritis (PsA) is a chronic inflammatory rheumatic disease strongly associated with psoriasis. We hypothesized that the presence of variant alleles in VDR may be associated with worse clinical outcomes. The aim of this study was to evaluate a possible association between the FokI and TaqI polymorphisms in the VDR gene and clinical markers of disease activity and functional status in PsA.

Method: Study included 68 patients with PsA. Diagnosis was confirmed according to fulfillment of CASPAR criteria for PsA. Disease activity for peripheral arthritis was evaluated using the DAPSA index; global assessment of disease activity and pain were assessed using VAS. BASDAI was used for the axial form of PsA. Functional ability was assessed by HAQ-DI and FACIT-F. BASFI was used for measuring the functional status of axial involvement. Overall functional mobility was assessed with TUG. Laboratory tests included genotyping of the FokI (rs2228570) and TaqI (rs731236), as well as CRP, ESR, IL-6, and 25(OH)D3. Significance was set at P < 0.05.

Results: Significant difference in FokI polymorphism was observed for intensity of pain, with the T/T genotype reporting worse outcomes than C/C (P = 0.049). BASDAI showed significant differences (P = 0.026), with T/T genotype having higher values than C/C genotype.

Conclusions: FokI polymorphism may have a potential role in modulating disease activity and pain perception in patients with PsA, whereas the TaqI polymorphism appears to have less impact on clinical outcomes. The findings emphasize the need for further research to better understand the genetic impact on disease severity in PsA.