Vitamin D Receptor Gene Polymorphisms and Bone Mineral Density in Korean Women / 대한내분비학회지

ABSTRACT

BACKGROUND: Bone mineral density(BMD) is thought to be under genetic control. Polymorphisms at the vitamin D receptor(VDR) gene have recently been shown to contribute to the genetic variability in bone mineral density in Caucasians. However, the relationship between VDR-RFLP(restriction fragment length polymorphisms) and bone mineral density is controversial. METHODS: The VDR-RFLP by BsmI, ApaI, and TaqI were studied in 250(77 premenopausal, 173 postmenopausal) Korean women. Bone mineral densities at the lumbar spine(L2-L4), femoral neck, greater trochanter, and Wards triangle were measured by DEXA(Dual Energy X-ray Absorptiometry; Lunar DPX-L, U.S.A.). RESULTS: There were significant differences in VDR gene allele frequency when compared with those in Caucasians. The BsmI polymorphism was consisted of 0.8% BB homozygotes, 12.4% Bb heterozygotes, and 86.8% bb homozygotes. The ApaI polymorphism was 6.8% AA homozygotes, 42.0% Aa heterozygotes, and 51.2% aa homozygotes, and the TaqI polymorphism was 83.2% TT homozygotes, 16.8% Tt heterozygotes, and 0% tt homozygotes. When these three VDR-RFLP were combined, bbaaTT(51.2%), bbAaTT(29.6%), and BbAaTt(10.0%) were found to be most frequent types. There were no significant relationship between VDR-RFLP and BMD measured at the 2nd to 4th lumbar spine in all subjects. But there were significant relationship between VDR-RFLP and BMD at the proxmial femur in all subjects. Compared with bb or bbaaTT(or bbAaTT), women with the Bb or BbAaTt genotypes had significantly lower bone mineral densities at the proximal femur in all subjects. When we restricted the analysis to early postmenopausal women less than 10 years since menopause, these findings were more pronounced. CONCLUSION: These results suggest that VDR-RFLP may affect on BMD at the proximal femur in Korean women. However, the frequencies of B, A, and t alleles are very low in Korean women compared to those of Caucasians, further studies will be needed, with larger sample sizes.