European Journal of Human Genetics vol:14 issue:Supplement 1 pages:333
European Human Genetics Conference edition:38 location:Amsterdam date:6-9 May 2006
Introduction: A start codon polymorphism within the Vitamin D receptor gene (VDR, T to C) results in a three amino acids shorter VDR protein with increased vitamin D-related transcriptional activity. Gender-specific effects of this polymorphism have not been studied yet.
Purpose: To investigate the association between the FokI polymorphism in VDR and muscle strength in older men and women.
Methods: The FokI polymorphism (rs2228570, Sequenom MassARRAY SNP) was genotyped in 99 men (67.1+/-4.2yr) and in 102 women (66.4+/-4.5yr). The peak torque of knee extension and flexion was measured at velocities of 0°/s, 60°/s, 180°/s and 240°/s. Genotype-phenotype associations were tested using AN(C)OVA with muscle+bone cross-sectional area of the thigh as covariate.
Results: FokI genotypes were in Hardy-Weinberg equilibrium in both men and women (p=0.14 and p=0.07, respectively). In men no significant association was found between FokI and any of the measured strength phenotypes. In women, however, significant association was found with all measurements of knee strength except peak torque flexion at 0°/s and 60°/s. For most of the strength measurements the heterozygous group performed less well in dynamic knee strength than both homozygous groups (p<0.05).
Conclusion: The VDR FokI polymorphism is associated with knee peak torque in senior women but not in men, confirming the possibility of gender-specific effects. The lack of association in men confirms results of other research groups. As this is the first study to investigate the association between the VDR FokI polymorphism and knee strength in women, further research will be necessary to elucidate these findings.