Association of bone dimensions with a parathyroid hormone gene polymorphism in women

We have recently shown that bone radio-grammetric dimensions are associated with vitamin D receptor gene polymorphism. Since parathyroid hormone (PTH) plays a central role in maintaining calcium homeostasis and in bone remode ling, we investigated whether bone radio-grammetric dimensions are associat ed with a PTH gene polymorphism in 91 healthy Caucasian women, who were pre menopausal at entry into the study. These women had assessments of bone by radiogrammetry every five years for a median period of 20 years (range 4-27 ). DNA was extracted from white blood cells. A segment of the PTH gene with a polymorphism at a BstBI restriction site was amplified by polymerase cha in reaction. Diameter, cortical thickness and cross-sectional area at stand ard sites of the metacarpals, radius and femur were measured with radiogram metry. Higher metacarpal diameter and cross-sectional cortical. area, and a slower decrease in radial cortical area with age, were associated with the absence of the BstBI restriction site of the PTH gene. PTH gene polymorphi sm accounts for about 7-9% of the total variances of bone dimensional varia bles. These findings suggest that the dimensions of long bones are influenc ed by allelic variations in the PTH gene or in genes nearby.