Vitamin D receptor (VDR) gene polymorphism in Egyptian vitiligo patients.

BACKGROUND: Vitiligo is an autoimmune dermatological disorder, precipitated by genetic and nongenetic factors leading to destruction of epidermal melanocytes. In Egypt, it has a prevalence rate of 1.2%. Vitamin D has stimulatory and protective effects on melanocytes and acts through its nuclear vitamin D receptor (VDR) on target cells. The consequences of polymorphisms in VDR have been previously studied for mapping their link with various disorders of autoimmune etiology. AIM OF THIS WORK: To study Apa-I and Taq-I VDR single-nucleotide polymorphisms (SNPs) and the risk to develop vitiligo. METHODS: Extracted genomic DNA from the venous blood of 60 patients and controls was amplified and analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for analysis of VDR gene polymorphisms. Serum 25-hydroxyvitamin D3 (25-OH-D3) level was measured using ELISA technique. RESULTS: The most common VDR genotypes were AA and TT among both groups with no significant difference. Analysis of the frequency of combinations of genotypes revealed AATT as the most common among patients (36.7%) while in the control group, AATt is the most common (33.3%) but no significant difference was noted on comparison of both groups. The genotype allele tt appeared to be more expressed in patients with marginal significance value (P 0.053). Serum 25-OH-D3 showed a relatively decreased level among patients and controls with no statistically significant difference. CONCLUSION: Although VDR SNPs are not correlated with vitiligo, the elevated frequency of tt genotype among vitiligo patients may suggest the risk to develop the disease.

Associations among two vitamin D receptor (VDR) gene polymorphisms (ApaI and TaqI) in acne vulgaris: A pilot susceptibility study.

BACKGROUND: Acne vulgaris (AV) pathogenesis is multifactorial. Vitamin D (VitD) plays an important role in sebocytes' differentiation and function. Most VitD functions are mediated by the nuclear VitD receptor (VDR) following binding of its biologically active form (1,25 dihydroxyvitamin D3). Genetic variations in VDR gene may cause significant receptor dysfunction and have been found to be associated with many inflammatory skin diseases. Two adjacent single nucleotide polymorphisms of VDR, ApaI (rs7975232) and TaqI (rs731236), were commonly studied. OBJECTIVE: To evaluate the association between VDR ApaI and TaqI gene polymorphism and AV. METHODS: This case control study included 30 Egyptian acne patients who attended Dermatology Outpatient Clinic of Al-Zahraa University and Misr University for Science and Technology Hospitals. Thirty age- and sex-matched healthy individuals participated as controls. VDR gene ApaI and TaqI polymorphisms were examined by polymerase chain reaction restriction fragment length polymorphism. Serum 25(OH)D was measured in all participants. RESULTS: Patients had significant decrease in ApaI A allele and AATT combined genotype (60%, 3.3%) than controls (78.3%, 20%), respectively, and significant increase in TaqI tt genotype and t allele (46.7%, 63.3%) than controls (13.3%, 41.7%), respectively. Patients showed significantly lower serum 25(OH)D3 concentration than controls. CONCLUSION: Polymorphisms of ApaI and TaqI may have a role in the pathogenesis of AV as A allele and AATT combined genotype could be considered protective against acne development and tt genotype and t allele may increase the risk of AV development. VitD deficiency can be considered as a risk factor for AV development.