Vitamin D–Receptor Gene Polymorphisms and Bone Density in Prepubertal American Girls of Mexican Descent

Abstract

Background Bone mass is under strong genetic control, and recent studies in adults have suggested that allelic differences in the gene for the vitamin D receptor may account for inherited variability in bone mass. We studied the relations of the vitamin D–receptor genotype to skeletal development and variation in the size, volume, and density of bone in children. Methods We identified three allelic variants of the vitamin D–receptor gene using the polymerase chain reaction and three restriction enzymes (ApaI, BsmI, and TaqI) in 100 normal prepubertal American girls of Mexican descent. We then determined the relations of the different vitamin D–receptor genotypes (AA, Aa, aa, BB, Bb, bb, TT, Tt, and tt) to the cross-sectional area, cortical area, and cortical bone density of the femoral shaft and the cross-sectional area and density of the lumbar vertebrae. Results The vitamin D–receptor genotype was associated with femoral and vertebral bone density. Girls with aa and bb genotypes had 2 to 3 percent highe...