Study of relationship of an androgen receptor CAG repeat polymorphism with postmenopausal osteoporosis / 中华老年医学杂志

ABSTRACT

Objective To study the relationship between a CAG repeat polymorphism of the androgen receptor (AR) gene and postmenopausal osteoporosis (PMO). Methods Genotypes for the AR polymorphisrn were determined by gene scan and DNA sequence methods in a case-control study,including 78 cases of PMO at femoral neck and 73 cases as controls, and 108 cases of PMO at lumbar spine (L2-4) and 60 cases as controls. Bone mineral density for the proximal femur and L2-4 was measured by NORLAND XR-46 dual-energy X-ray absorptiometry. The relationship between the CAG repeat polymorphism and PMO was investigated. Results Eleven different allelic variants,containing 18, 20, 21, 23, 24, 25, 26, 27, 28, 29, and 30 CAG repeats were detected, 16 genotypes were present in the subjects. There were no significant differences in the genotype and allele distributions of (CAG) n polymorphism between PMO group (SS 25.6 %, SL 39.7%, LL 34.6 % ;S45.5%,L54.5%) and control group (SS 23.3%,SL=45.2% ,LL31.5%;S45.9%,L54.1%) at the femoral neck site (all P＞0.05). The risk of PMO at femoral neck in females with the genotypes of SL (0R0.798,95%CI0.335～1.797), the LL (0R0.998,95%CI0.425～2.341), and the combined SL and LL (OR0.880, 95% CI 0.419～1.852) were not significantly increased in comparison with those of females with the SS genotype (all P＞0.05). There were no significant differences in the genotype and allele distributions of (CAG)n polymorphism between PMO group(SS 18.5%, SL 49.1%, LL 32.4%;S43.1%, L 56.9%) and control group (SS 21.7%, SL45.0% ,LL33.3% ;S44.2% ,L55.8%) at the L2-4 site (P＞0. 05). The risk of PMO at L2-4 in females with the genotypes of SL (OR1. 276,95%CI0. 552～2. 950), the LL (OR1. 137,95%CI0.468～2.766), and the combined SL and LL (OR 1. 217,95% CI 0. 556 ～2. 663 ) were not significantly increased in comparison with those of females with the SS genotype (all P＞0.05). After adjustments for age, postmenopausal period, menopausal age, and body mass index, the logistic regression analyses revealed the (CAG)n polymorphism was not significantly associated with PMO at the femoral neck and L2-4 site (all P＞0.05). Conclusions The CAG repeat polymorphism in the AR gene may not be associated with PMO at the femoral neck and L2-4 site.