POLYMORPHISMS OF VITAMIN-D-RECEPTOR GENE AND ITS ASSOCIATION WITH BONE-MINERAL DENSITY AND OSTEOCALCIN IN CHINESE

Objective To explore thr distribution frequencies of vitamin D recepto r (VDR) gene polymorphisms in Chinese and the relationship between VDR genotypes and bone mineral density (BMD) or serum osteocalcin level i n Chinese women. Methods Polymorphisms of VDR gene were analyzed by po lymerase chain reaction (PCR) to amplify thc DNA sequence and three re striction enzymes (namely BsmI, ApaI and TaqI) to digest the PCR produ cts in 223 subjects. Some of the VDR genotypes were also confirmed by Southern hybridization analysis. BMD was measured at the spine and pro ximal femur by dual-energy S-ray absorptiometry (DEXA). Serum osteocal cin concentrations were determined by radioimmunoassay. Results Chines e had high frequencies of ''b,a,T'' alleles, 95%, 75% and 95% respecti vely, which were much different from Caucasians. ''BB'' or ''AA'' geno type had tendency for higher BMD at some sites in the group of young w omen, whereas in the group of postmenopausal women, ''bb'' or ''aa'' g enotype had relationship with lower BMD at femoral neck and trochanter . Furthermore, no relationship were found between VDR genotypes and th e serum osteocalcin level in Chinese women. Conclusions Allele frequen cies of VDR gene in Chinese are different from those in Caucasians. VD R gene polymorphisms are associated with BMD in Chinese but in a diffe rent pattern from other reports. Further study on predicting function oi VDR for osteoporosis is necessary.