Association of vitamin D binding protein and vitamin D receptor gene polymorphisms in Iranian patients with chronic periodontitis

Chronic periodontitis (CP) is a multifactorial disease and the most common type of periodontitis mainly caused by microbial plaque. Insufficient oral hygiene may initiate CP and it can be further modified and progressed by environmental and genetic susceptibilities. The aim of the present study was to investigate the association between VDBP (rs7041 and rs4588) and (Taq 1-rs7975232 and Apa1-rs731236) SNPs of VDR gene receptor and susceptibility to CP in an Iranian population. Sixty nine cases with diagnosis of CP and 78 matched healthy controls engaged in this study. Three-milliliter peripheral blood samples were obtained for DNA isolation. Genotype analysis was performed using restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR). Chi-squared test was used for distribution of genotypes analysis. 95% confidence interval (CI) was used to calculate the odds ratio (OR). Deviation from Hardy–Weinberg equilibrium, multiple inheritance models, linkage disequilibrium and haplotype analysis were done. There was no significant association between genotype/phenotype of VDBP’s SNPs (rs7041 and rs4588) and occurrence of chronic periodontitis (p value = 0.401) Moreover, no statistically significant association was found between chronic periodontitis and Taq1 (rs731236) (p value = 0.401) and Apa1 (rs7975232) (p value = 0.248). The analysis of alleles and genotypes’ distribution between different severities of chronic periodontitis and healthy controls indicated a significant association between various severities of chronic periodontitis and Apa1 (rs7975232) (p value = 0.011) and VDBP’s SNPs (rs7041 and rs4588) (p value = 0.038), whereas no statistically significant association was observed between various severities of chronic periodontitis and Taq1 (rs731236) (p value = 0.278). Our results suggest a significant association between severity of chronic periodontitis and Apa1 (rs7975232) and VDBP SNPs (rs7041 and rs4588). Sequencing studies on different populations may release other results due to the genetic and racial diversity.