Is there any association between a vitamin D receptor gene polymorphism (FokI) and pemphigus vulgaris?

Pemphigus vulgaris (PV) is an autoimmune bullous disease of the skin and mucous membranes caused by activation and proliferation of T cells, production of Th2 cytokine profile and pathogenic antibodies. Vitamin D is a probable immunodeviator to Th2, which its actions are mediated through the vitamin D receptor (VDR). FokI is the only single nucleotide polymorphism (SNP) leading to VDR protein with a different structure and function. For the first time, we focused on FokI VDR SNP to evaluate its potential role in the genetic susceptibility to PV, particularly in the Iranian population that has a high prevalence of pemphigus. In this case-control study, DNA samples of 122 PV patients and 233 healthy controls were extracted, and FokI genotyping was performed using the PCR-RFLP method. The mean allele frequencies of F and f alleles in the PV and control groups were 75% and 25%, and 78% and 22%, respectively, showing no significant difference. The genotype frequencies for FF, Ff, and ff genotypes in the case group were 57.4%, 35.2%, and 7.4%, respectively. In the control group, the frequencies were 60%, 36%, and 4%, respectively. Statistical analysis showed no significant difference between the two groups. The present study concluded the frequencies of F and f alleles as approximately 77% and 23% in the gene pool of the Iranian population. Additionally, it showed no association between the FokI alleles and PV in this population.