Evidence of association of vitamin D receptor Apa I gene polymorphism with bone mineral density in postmenopausal women with osteoporosis

Abstract

The vitamin D receptor (VDR) was the firstcandidate gene to be studied in relation to osteoporosis, andmost attention has focused on polymorphisms situated nearthe 3' flank of VDR. The aim of this study was toinvestigate the association about VDR gene Apa I polymorphismwith bone mineral density (BMD) in postmenopausalwomen with osteoporosis. We studied a total of 136postmenopausal women with a mean age of 56.36±10.29 years. Among them, a total of 75 had osteoporosis,37 had osteopenia, and 24 had normal BMD. Venous bloodsamples were obtained for evaluation of bone metabolismand genotyping. The VDR Apa I genotype was determinedby polymerase chain reaction-restriction fragment lengthpolymorphism. BMDs at the lumbar spine and hip weremeasured by dual-energy X-ray absorptiometry. Postmenopausalwomen with aa genotype had significantly lowerBMD values (grams per centimeter square) at lumbar spinescompared to persons with AA genotype. Also, postmenopausalwomen with AA genotype had significantly higherserum Ca level than the subjects with aa genotype. Inconclusion, our result may indicate that VDR Apa I genepolymorphism may be responsible for a important part ofthe heritable component of lumbar spine BMD in postmenopausalwomen, possibly related to impaired calciumabsorption from the bowel.