The associaton of GC RS2282679 polymorphism with vitamin D levels and osteoporosis in postmenopousal women

Vitamin D deficiency is a risk factor for osteoporosis. Deficiency of Vit D-binding protein (VDBP) affects vit D binding and may impair bone mineralisation. VDBP is encoded by the Gc gene on chromosome 4q11-q13. This study aims to search the association of rs2282679 polymorphim in GC in intron 12, with vitamin D levels and bone mineral density in postmenopausal women. Healthy post menapousal women (n=100) were enrolled in this study. Standard risk factors such as smoking, alcohol consumption and demographic data was taken from all participants. Peripheral blood is taken from participants, serum was kept for vitamin D measurements, and blood is used for DNA analysis. Intron 12 region of GC gene is amplified by nested PCR and rs2282679 variant is analyzed by restriction fragment length polymorphism (RFLP) method. Vit D levels are measured by LC MSMS method and bone mineral density results are taken as T-Scores of femure and AP spine. As a result Vitamin D levels are founded to be very low in this cohort (median:9(13)). In rs2282679 polymorphism, genotype frequencies of AA, AC and CC are 0.14, 0.67 and 0.19 respectively. The only statistically significant result is the association between vitamin D levels and genotypes. Vitamin D levels are significantly higher (p=0.042) in wild type homozygotes vs polimorfic cases (AA vs AC+CC). Also, AA vs CC has a significant difference in vitamin D levels (0.025). This results are consistent with the previous articles about rs2282679 polymorphism. Bone mineral density results are not significantly associated with the polimorphism.