Çukurova Üniversitesi Tıp Fakültesi Dergisi (Feb 2014)
Association of Estrogen Receptor Alpha Gene XbaI and PvuII Polymorphisms with Postmenopausal Osteoporosis
Abstract
Purpose: Osteoporosis is a multifactorial disease characterized by a decrease bone mineral density (BMD) and micro-architectural deterioration of bone structure. Although several environmental factors are known to have influences on BMD, genetic contribution to the pathogenesis of osteoporosis has recently been recognized. The existence of about 150 candidate genes which have effects on bone mass was reported but the degree of these effects and interaction of genes and environment are presently unclear. In this study, it was aimed to investigate any relationship between BMD values of lomber vertebra and femoral neck, osteoporosis-related criteria and ERα gene XbaI, PvuII polymorphisms. Material and Methods: We evaluated the relationship between the osteoporotic factors and ERα gene XbaI, PvuII polymorphisms in 107 postmenopausal women (73 osteoporotic as study group and 34 non-osteoporotic as a control group) by using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) technics. Data about the osteoporosis-related factors about all subjects were either based on the laboratory analyses and results of a standardized questionnaire. Results: The distributions of genotype, allele and haplotype frequencies of both XbaI and PvuII polymorphisms were not significantly different between osteoporotic and control group. In control group of XbaI polymorphism, minor allel was “X” (nucleotide G) with the frequency MAF=0,457 but in osteoporotic women it was “x” (nucleotide A) with MAF=0,467 and in control group of PvuII polymorphism, minor allele was “P” (nucleotide C) (MAF=0,485) and in osteoporotic women it was “p” (nucleotide T) (MAF=0,418). In patients xx genotypes of XbaI polymorphism had significantly higher femoral neck-lomber average BMD value than XX and Xx genotypes (p=0,05) while no significant difference was found among control genotypes. PvuII genotypes showed no differences for femoral neck-lomber BMD values both in patients and controls. For the family history of osteoporosis, PP, Pp and pp genotypes did not significantly differ in controls but differences among patient genotypes were significant reaching the highest ratio (% 85.7) in PP genotypes (p=0,04). Xxpp genotyped patients who exposed to sun over 15 minutes per day had higher BMD values than in patients who had no sun exposure (p=0.01) but there was no difference in control group. None of the other criteria related to osteoporosis was found to be associated with XbaI, PvuII polymorphisms. Conclusion: Osteoporotic women have higher femoral neck-lomber BMD values for xx genotypes but all osteoporotic women have lower x and p allele frequencies. Although there was an insignificant difference for XbaI genotypes between patients and controls, less occurrence of \"x\" allel associated with higher BMD values in patients may be of some clinical diagnostic importance.
