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

Background: Several types of polymorphisms in vitamin D receptor (VDR) have been found in psoriasis. Aim: 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. Subjects and Methods: Clinical examination, serum (25(OH)D) levels measurement, molecular studies, TaqI genotyping by PCR and RFLP subjected for the two groups. Results: : T/t genotypes of TaqI polymorphism genotypes were most common in patients, while t/t genotypes were more abundant in healthy subjects. The T allele was high in the patient group in comparing to 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 T/T and t/t (P=0.004). Moderate psoriatic patients with the T/t genotype have relatively high 25(OH)D) levels than moderate patients with the T/t and t/t genotypes (P=0.001). Conclusion: 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.