Evaluation of eNOS gene polymorphisms in relation to BMD in postmenopausal women

Objective

The aim of the present study was to evaluate the relations between T⁻⁷⁸⁶C and Glu298Asp polymorphisms of the endothelial nitric oxide synthase (eNOS) gene and BMD in postmenopausal Turkish women.

Methods

The T⁻⁷⁸⁶C and Glu298Asp polymorphisms were genotyped by PCR-RFLP method in 311 postmenopausal osteoporotic women (OP) and in 305 age-matched postmenopausal females (CG) with normal BMD.

Results

None of the SNPs of the eNOS gene was significantly associated with BMD at the lumbar spine, femoral neck, Ward's triangle and femoral trochanter in the combined group. Mean BMD values were therefore found to be similar across the genotypes in postmenopausal Turkish women. However, there was a significant association between the T⁻⁷⁸⁶C polymorphism and BMD values at the lumbar spine in the normal control group (P = 0.005), and at the femoral trochanter in the osteoporotic patients (P = 0.046). The mean value of the lumbar spine BMD in the normal controls was significantly higher in women with the TC genotype of the T⁻⁷⁸⁶C polymorphism than in women with the TT genotype (P = 0.0012). Women with the CC genotype of the T⁻⁷⁸⁶C polymorphism in the osteoporotic patients had significantly higher BMD value at the femoral trochanter than those with the TC (P = 0.018) and TT genotypes (P = 0.024). Frequencies of the TC heterozygotes for T⁻⁷⁸⁶C polymorphism were significantly higher among osteoporotic subjects than normal controls. Also, the CC and TT genotype frequencies of control group were significantly higher than those of the osteoporotic group at the femoral neck.

Conclusions

We conclude that, although the biological role of the nitric oxide synthases is well established, our study does not suggest that eNOS gene polymorphisms, T⁻⁷⁸⁶C and Glu298Asp, are major contributors to adult bone mineral density in the postmenopausal Turkish women.