Identification and Association of CYP2R1, CYP27B1, and GC Gene Polymorphisms with Vitamin D Deficiency in Apparently Healthy Population and in Silico Analysis of the Binding Pocket of Vitamin D3.

Vitamin D deficiency is highly prevalent in Pakistan, but there is limited data on its genetic aspects. This case-control pilot study aimed to determine the association of rs782153744, rs200183599, rs118204011, and rs28934604 with vitamin D deficiency along rs7041 which has been studied in our population. The DNA of a total of 600 subjects (300 cases and 300 controls) was extracted and genotyped by tetra ARMS PCR, followed by Sanger DNA sequencing of exon 4 of the CYP2R1 and CYP27B1 genes and exon 8 of the GC gene. SNP Stat was employed to analyze the data, while logistic regression was used to calculate the p-values and odds ratios (ORs). The R package version R studio (2025.05.1) Build 513 was used to statistically analyze rs782153744. In silico modeling of wild and mutant CYP2R1 and GC proteins was performed in Swiss-Model, Swiss-Dock, Discovery Studio, and PyMol using 3c6g and IJ78 as templates to perform binding pocket analysis of vitamin D3. The rs782153744 showed a protective association in the additive (OR: 0.15, 95% CI: 0.08-0.27, p-value < 0.001), recessive (OR: 0.19, 95% CI: 0.10-0.33, p-value < 0.001), and dominant (OR: 0.19, CI = 0.10-0.33, p-value < 0.001) models, while GC rs7041 (T > A, T > G) displayed a p-value < 0.0001 across all genetic models. Sanger sequencing yielded insignificant results, and the SNPs rs200183599, rs118204011, and rs28934604 had no significant association with vitamin D deficiency. The molecular pocket analysis of wild and mutant CYP2R1 proteins carrying rs782153744 polymorphisms revealed no changes. GC proteins carrying the rs7041 polymorphism revealed a shift in their 3D and 2D configuration, as well as a change in the amino acid residue of the binding pocket of VD3. The risk-associated rs7041 and protective rs782153744 variants back genetic screening for vitamin D deficiency risk stratification, allowing targeted supplementation in predisposed subjects and assisting in formulating a genotype-specific therapeutic approach.