Association of Vitamin D Receptor Gene Polymorphism (FokI) with Susceptibility to Musculoskeletal Tuberculosis: A Case-Control Study from Central India.
AIM AND BACKGROUND: Musculoskeletal tuberculosis (MSKTB) constitutes a significant proportion of extra-pulmonary tuberculosis (TB), particularly in developing countries like India. While host genetic factors are known to influence susceptibility to TB, the Vitamin D receptor (VDR) gene, particularly the FokI polymorphism, has been implicated in immune regulation and susceptibility to pulmonary and extra-pulmonary TB, data on genetic predisposition to MSKTB remain limited. The present study aimed to investigate the role of the VDR FokI gene polymorphism in determining susceptibility to MSKTB. MATERIALS AND METHODS: This study included 110 patients with confirmed MSKTB and 112 controls without TB, recruited from a tertiary care institution over a 3-year period. Clinical and demographic data were obtained. Genomic DNA was extracted from peripheral venous blood samples, and VDR FokI polymorphism was detected using polymerase chain reaction-based restriction fragment length polymorphism analysis. Genotype and allele frequencies were compared using a Chi-square test, and odds ratios (OR) with 95% confidence intervals (CI) were calculated. RESULTS: The ff genotype was significantly more frequent in cases (17.3%) compared to controls (9.8%) and was associated with increased risk of MSKTB (OR = 2.30, 95% CI: 1.03-5.15, P = 0.04). The polymorphic f allele frequency was also significantly higher in cases than controls (38.2% vs. 28.1%; OR = 1.58, 95% CI: 1.05-2.37, P = 0.023). However, the dominant and recessive genetic models showed a non-significant association. Demographically, MSKTB was more common among females, individuals from rural backgrounds, those of lower socioeconomic status, and those with low body mass index. CONCLUSION: The VDR FokI polymorphism, particularly the ff genotype and f allele, is associated with increased susceptibility to MSKTB. These findings highlight the potential role of genetic factors in MSKTB and may aid in identifying at-risk populations.