Association of rs10741657 polymorphism in CYP2R1 gene with apparently healthy vitamin-D deficient Pakistani subjects
Objectives: To determine the association of polymorphism rs10741657 in the CYP2R1 gene with vitamin D deficiency in apparently healthy subjects. Method: The prospective, case-control study was conducted from June 2023 to January 2024 at the CREAM Lab of Army Medical College, Rawalpindi, and comprised vitamin D-deficient cases in group A and healthy controls in group B. Genotyping of rs10741657 polymorphism in the CYP2R1 gene was performed using allele-specific polymerase chain reaction (AS-PCR). Genotypic and allelic frequencies, Hardy–Weinberg equilibrium, and genetic inheritance models were analysed using SNPStats, a web-based statistical software for genetic association studies. Results: Of the 300 subjects with a mean age of 43.56 ± 15.26 years, 150 (50%) were in group A, comprising 91 (61%) females and 59 (39%) males, with a mean age of 44.49 ± 15.12 years. There were 150 (50%) controls in group B, including 83 (55%) males and 67 (45%) females, with a mean age of 42.63 ± 15.40 years. The genotypic frequencies in group A were A/A 45(30%), A/C 101(67.34%), C/C 4(2.66%). The corresponding values in group B were 39(26%), 110(73.34%) and 1(0.66%). The allele frequency of A was 191 (64%) in vitamin D-deficient cases and 188 (63%) in healthy controls (p = 0.8775), while the C allele frequency was 109 (36%) in cases and 112 (37%) in controls (p = 0.8401). The genotype frequencies in cases were A/A 45 (30%), A/C 101 (67%), and C/C 4 (2.67%), compared to A/A 39 (26%), A/C 110 (73%), and C/C 1 (0.67%) in controls, with no statistically significant difference observed between the groups (p > 0.05). The inheritance genetic models suggested no association with vitamin D deficiency (p>0.05); codominant model – A/C odds ratio 0.70 (95% confidence interval: 0.45-1.23), C/C odds ratio 4.00 (95% confidence interval: 0.45-36.96); dominant model odds ratio 0.80 (95% confidence interval: 0.49-1.35); recessive model odds ratio 4.00 (95% confidence interval: 0.45-36.96); and overdominant model odds ratio 0.70 (95% confidence interval: 0.45-1.23). Conclusion: The A allele was found to be the most common variant of rs10741657 in both the groups. The rs10741657 polymorphism was not a risk for the susceptibility to vitamin D deficiency. No correlation of genotype with serum vitamin D levels was noted. Key Words: Allele-specific polymerase chain reaction, Single nucleotide polymorphism, Calcitriol, 25 Hydroxylase, Vitamin D binding protein.