Estrogen Receptor-α rs9340799 Polymorphism Influences Bone Mineral Density in Women Over 60 Years of Age and Women Who are Postmenopausal for More than 10 Years

Abstract

Background: Osteoporosis is a multifactorial disorder where genetic and environmental factors contribute to changes in bone mineral density. Several genetic polymorphisms are associated with low bone mineral density and osteoporosis risk, including estrogen receptor-α rs2234693 and rs9340799 single nucleotide polymorphisms. Objective: To determine the allele frequencies of these polymorphisms among postmenopausal Jordanian women and to assess their association with low bone mineral density and osteoporosis among studied subjects. Methods: This cross-sectional study enrolled 450 postmenopausal Jordanian women having dual-energy X-ray absorptiometry scans at the National Center for Diabetes, Endocrinology, and Genetics. The study protocol was approved by this center "Institutional Review Board." The estrogen receptor-α gene sequence containing rs2234693 and rs9340799 polymorphisms was identified by polymerase chain reaction, followed by restriction fragment length polymorphism. Results: The wild-type allele frequencies of rs2234693 (T) and rs9340799 (A) were 54% and 59%, respectively. The rs9340799 GG genotype was significantly associated with lower femoral neck T-scores in women who were postmenopausal for more than 10 years (p = 0.023) and was significantly associated with lower lumbar spine (p = 0.033) and femoral neck (p = 0.002) T-scores in women older than 60 years of age. However, there was no association between rs2234693, rs9340799, or their haplotypes with osteoporosis or bone mineral density T-score values. The two polymorphisms were in Heidy-Weinberg equilibrium and exhibited strong but incomplete linkage disequilibrium. Conclusion: The data suggest that rs9340799 polymorphism may render some women more susceptible to osteoporosis than others.