Abstract
Background: Osteoporosis is the bone disease characterized by demineralization of the bone. One of the most important genetic factors responsible for the osteoporosis is the vitamin D receptor (VDR) gene polymorphism. A translocation polymorphism which changes the codon from ATG to ACG has been associated with bone mineral density (BMD) variation and severity of the disease in patients of osteoporosis. The objective of the study was to find association of VDR Fok1 polymorphism with bone mineral density
Methods: This case control study was design to find the association of the VDR Fok1 polymorphism with bone health in Pakistani osteoporotic patients. The study was conducted at Islamabad Diagnostic center from 2014 to July 2016. Total of 156 participant (osteoporatic patients n = 78 and normal health controls n = 78 case control) were enrolled in the study. Polymerase chain Reaction restriction length polymorphism (PCR-RFLP) was used to genotype VDR Fok1 polymorphism. Bidirectional sanger sequencing was used to verify the PCR-RFLP results with randomly picked n = 10 samples from both controls and patients. Commercial kits were used to estimate serum calcium and vitamin D level while dual-energy X-ray absorptiometry scan was used to measure the bone mineral density. The data were analyzed statistically using Statistical package for the social sciences (SPSS).
Result: F-allele increased the risk for decrease bone mineral density and osteopenia nearly threefold [Odds Ratio (OR): 2.8; 95% Confidence Interval (CI): 3.2-19.0; p ≤ 0.001]. The genotype frequencies (Ff + ff vs. FF) showed an increase risk of disease (OR = 6.79; 95% CI = 3.41-22.6; p = <0.001). The OR cannot be calculated for recessive model since there was no ff genotype in the control group. Serum vitamin D and calcium was significantly lower in patients with mutant polymorph and their BMD was also significantly lower as compared to controls
Conclusion: VDR Fok1 polymorphism is significantly associated with low mineral bone density, serum calcium and serum vitamin D level in Pakistani cohort.