Association of vitamin D deficiency with vitamin D binding protein (DBP) and CYP2R1 polymorphisms in Iranian population

Abstract Background Micronutrients are crucial for the promotion of human's well-being via biological processes. Vitamin D is one of the most important ones with its vital role in calcium homeostasis in our body. Vitamin D deficiencies would definitely bring about various skeletal and non-skeletal disorders. In this study we have assessed the influence of two single-nucleotide polymorphisms (SNPs) of GC gene (vitamin D binding protein gene), and one of the CYP2R1 (25 Hydroxylase enzyme's), on vitamin D deficiency and insufficiency. Methods 196 healthy adults' Iranian population (the real Persian race living in Fars province) cases were participated in this study, dividing into three groups of: normal, deficient and insufficient, considering their vitamin D concentration. The blood specimen was obtained and DNA was extracted from leukocytes. Following this, restricted fragment length polymerase chain reaction (RFLP-PCR) was used for genotyping throughout the processes and two SNPs of DBP (vitamin D binding protein), rs4588 and rs7041, and one of CYP2R1, rs10741657, were assessed. Meanwhile, we have evaluated the serum levels of 25-Hydroxy vitamin D3 with ELISA method. Results The results showed no significant differences between three aforementioned groups in terms of seven various nature-nurture factors. Between three SNPs which were genotyped and assessed, rs7041 was the one that have drawn a significant distinction between groups. Its GT and TT genotypes were remarkably higher in insufficient and deficient groups respectively. Moreover, four haplotypes of rs4588 and rs7041 were evaluated and CT and AT ones illustrated a dramatic frequency rates in deficient and insufficient groups in turn. Neither of the remaining haplotypes (CG, AG) revealed significant frequencies among the groups though. Conclusion We have concluded that both DBP and CYP2R1 SNPs could be effective for the regulation of vitamin D levels, however rs7041 and its genotypes was by far the most effective ones in vitamin D deficiencies.