The Relationship Between AHSG Gene With BMD And Bone Size In Chinese Population

Osteoporosis is an important health problem in the world. Alpha2-HS glycoprotein (AHSG) is involved in bone formation and metabolism and has been considered as an important candidate gene for osteoporosis, bone mineral density (BMD) is an important risk factor for osteoporosis and bone size is an independent determinant of osteoporotic fracture. In this study, we simultaneously tested linkage and/or association of the AHSG gene with the variation of BMD and bone size. A sample of 1, 260 subjects from 401 Chinese nuclear families (including both parents and their daughters) were studied. The daughters' ages ranged from 20 to 45 years. All the subjects were genotyped by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) at polymorphic Sac I site inside the exon 7 of the AHSG gene. This polymorphism involves a nucleotide substitution of C to G at the middle nucleotide of the codon at amino acid position 238 resulting in the replacement of threonine (ACC) with serine (AGC). BMD (g/cm2) and bone size (cm2) was measured at the lumbar spine and the hip region using dual-energy X-ray absorptiometry (DXA). Using the QTDT (quantitative trait transmission disequilibrium test), we did not find significant results for association or linkage between the AHSG gene and BMD variation at the spine or hip. Our data did not provide evidence to support the AHSG gene as a quantitative trait locus (QTL) for the BMD variation in a Chinese population. As to bone size tested by quantitative transmission disequilibrium test, we found significant total association at the intertrochanteric region (p=0.019) and total hip (p=0. 035), whereas no significant'results for linkage, within-familyassociation. For the father group, significant evidence of association (test via ANOVA) was found at the intertrochanteric region (p=0. 005) and total hip (p=0. 010), but was not detected in the mother or the daughter groups. Our study shows that the AHSG gene may be associated with bone size at total hip (especially at the intertrochanteric region) in Chinese men. However, our data do not suggest that the AHSG-5ac I marker is closely linked to a QTL for bone size variation in Chinese.