Bone Abstracts

Objective: The enzyme methylenetetrahydrofolate reductase (MTHFR) is known to play an important role in the removal of circulating homocysteine via the methionine cycle. C677T polymorphism is associated with higher plasma homocysteine levels, which could affect collagen maturation. The aim of the present study was to examine possible associations of C677T polymorphism in the MTHFR gene with a variability of femoral (F-BMD), spinal BMD (S-BMD) together with circulating alkaline phosphatase (ALP), osteocalcin (OC; formation markers), beta-CrossLaps (CTx; resorption marker) and fracture incidence in 334 Slovak postmenopausal women.

Material and Methods: Postmenopausal women (62.70±0.53 years) were selected according to strict inclusion criteria. Genetic polymorphism was detected by PCR-RFLP method. Genotype frequencies and frequencies of fractures were tested using the chi-square test. The differences of quantitative variables between the genotypes were analyzed by covariance analysis (GLM procedure) after correction of the measurements for age and BMI.

Results: The prevalence of each genotype was 46.41, 43.11 and 10.48% for CC, TC, and TT genotypes respectively. We reported a statistically significant effect of MTHFR/TT genotype on F-BMD (P<0.05). Individuals carrying TT genotype disposed significantly lowest T-score values in comparison with other genotypes. Similarly, spinal BMD (P=0.074) values were decreased in subjects with TT genotype but nonsignificantly. We also found that TT genotype had the highest concentrations of all analyzed bone turnover markers (ALP, OC, CTx), which could indicate a trend of increased remodelation rate in this group. Comparison of fracture incidence between the genotype groups also showed no significant differences for the polymorphisms.

Conclusion: Our results suggest that MTHFR/C677T polymorphism could contribute to the genetic regulation of BMD or bone turnover markers in population of Slovak postmenopausal women. All procedures were approved by the Ethical Committee of the Specialized Hospital of St. Svorad in Nitra (Slovakia).