Association of Vitamin D Receptor Gene Polymorphisms with Serum 25-Hydroxyvitamin D Levels in Lithuanian Adults with Atopic Dermatitis: A Case-Control Study.

Atopic dermatitis (AD) is a chronic inflammatory skin disease increasingly prevalent in adults. Vitamin D plays an important role in regulating immune responses, cellular differentiation, and inflammation. Several single-nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene have been suggested as biomarkers of AD susceptibility and severity. The aim of this study was to investigate six SNPs in the VDR gene (rs3847987, rs731236, rs7975232, rs1544410, rs2228570, and rs11168293) and their association with AD and blood biomarkers. Genotyping was performed in 91 adult patients with AD and 102 controls using real-time polymerase chain reaction. The genotype and allele distributions did not differ significantly between AD patients and controls. However, the G and T alleles of VDR rs731236 and rs1544410 were more frequently detected in individuals with serum 25-hydroxyvitamin D (25(OH)D) levels above 30 ng/mL. In contrast, the VDR rs7975232 C allele appears to be associated with lower odds of having a serum 25(OH)D level above 30 ng/mL. In genotype-stratified analysis, the T allele of VDR rs11168293 was more prevalent among individuals with eosinophil counts of 300 cells/μL. These findings suggest that VDR polymorphisms may contribute to variability in vitamin D status and inflammatory responses in adults with AD.