Title: Association of VDR rs2228570 (FokI) and rs1544410 (BsmI) Polymorphisms with Serum Vitamin D Status in a Clinical Cohort
Authors: Ahmed O. Ahmed, Hani M. Abdalla, Yousif A. Mohammed, Adil Mergani, Amir M. Dafalla, Amira S. Khalafalla, Abuagla M. Dafalla,, Marwa A. Ahmed, Bakri Y. M. Nour
Volume: 10
Issue: 9
Pages: 182-188
Publication Date: 2026/09/28
Abstract:
Background: Vitamin D status is influenced by environmental, nutritional, physiological, and genetic factors. The vitamin D receptor (VDR) is a key mediator of vitamin D signalling, and common VDR variants have been investigated as potential modifiers of vitamin D-related phenotypes. The present study evaluated the association of VDR rs2228570 (FokI) and rs1544410 (BsmI) polymorphisms with serum vitamin D status. Methods: Seventy-seven participants were classified according to the study-defined serum vitamin D categories as deficient (<20 ng/mL; n=68) or insufficient (20-30 ng/mL; n=9). Genotype and allele distributions for rs2228570 and rs1544410 were assessed, Hardy-Weinberg equilibrium (HWE) was evaluated, and inherited genetic models were examined using logistic regression with adjustment for a continuous quantitative covariate, as reported in the source analysis. Results: Vitamin D deficiency was present in 68/77 participants (88.31%). For rs2228570, the overall genotype distribution was C/C 55 (71%), C/T 17 (22%), and T/T 5 (6%). The C/T genotype was absent in the insufficient group, in which C/C accounted for 8/9 (89%) and T/T for 1/9 (11%). The overdominant model showed a statistically significant association with vitamin D classification (P=0.047), whereas the codominant, dominant, recessive, and log-additive models were not statistically significant (P>0.05). For rs1544410, no tested genetic model was statistically significant (all P>0.05). Conclusion: In this sample, rs2228570 showed an association with vitamin D classification under an overdominant model, while rs1544410 did not show evidence of an independent association. The finding for rs2228570 should be interpreted cautiously because the insufficient group was small and contained no C/T heterozygotes, producing an unstable effect estimate. Larger, adequately powered studies incorporating environmental and clinical determinants of vitamin D status are needed.