TaqI polymorphism T/t genotypes at the vitamin D receptor gene (VDR) are associated with increased serum vitamin D levels in mild and moderate psoriasis vulgaris: A pilot study.

Abstract

Several types of polymorphisms in vitamin D receptor (VDR) have been found in psoriasis. This study looked at the role of the TaqI polymorphism in the VDR gene as a factor in changing plasma 25-hydroxyvitamin D [25(OH)D] levels in psoriasis patients and to see if it had any relationship with disease severity. Clinical examination, serum 25(OH)D level measurement, molecular studies and TaqI genotyping by PCR and RFLP were performed for the two groups. The T/t genotypes of TaqI polymorphism genotypes were most common in patients, while the t/t genotypes were more abundant in healthy subjects. The T allele was high in the patient group in comparison with the normal subjects, but there were no significant differences (p= 0.421). Patients with T/t TaqI genotypes had higher levels of 25(OH)D than those with T/T and t/t (p= 0.004). Moderate psoriatic patients with the T/t genotype had relatively high 25(OH)D levels compared with moderate patients with the T/t and t/t genotypes (p= 0.001). The increase in 25(OH)D titers in moderate patients is greater than that in mild and severe patients. T/t genotypes are associated with increased 25(OH)D levels in moderate and mild patients.