Association between bone mineral density and polymorphisms of the VDR, ERalpha, COL1A1 and CTR genes in Spanish postmenopausal women

The influence of ESR1 polymorphisms on selected hormonal, metabolic and mineral balance markers in women with hyperandrogenism

Hyperandrogenism is the most common endocrine disorder in women, characterized by an imbalance in normal estrogen and androgen levels in the blood. Androgens influence bone mineral density, body mass composition, muscle mass, mental state, and the regulation of sexual function.. The aim of the study was to assess the effect of estrogen receptor α gene (ESR1) polymorphisms on selected markers of bone metabolism and hormonal parameters in women with hyperandrogenism. The study group included 80 young women with hyperandrogenism who underwent measurements of bone mineral density (BMD), and determination of hormonal and metabolic parameters. Enzyme immunoassays were used to measure leptin, sRANKL (soluble receptor activator of nuclear factor-kB ligand), osteoprotegerin and 25-OH vitamin D total levels. An analysis of ESR1 gene polymorphisms was performed using the real-time PCR method. A relationship was demonstrated between the concentration of free estradiol (FEI) and the concentration of 17-OH-progesterone, and the ESR1 gene polymorphisms: rs3020314 (p = 0.031, p = 0.026 respectively) and rs1884051 (p = 0.033, p = 0.026 respectively). In conclusion, the ESR gene polymorphisms may be associated with hormonal disturbances in the concentration of estrogens and androgens, in hyperandrogenism in young women which may indirectly affect bone mineral density. However, no statistically significant relationships between the studied polymorphisms and the selected parameters of mineral metabolism have been demonstrated..

Circulating MicroRNA Expression, Vitamin D, and Hypercortisolism as Predictors of Osteoporosis in Elderly Postmenopausal Women

BACKGROUND

MicroRNAs (miRNA) identified as critical molecular regulators for bone development, function, and modeling/remodeling process and could be predictable for osteoporotic fractures in postmenopausal elderly women.

AIM

The potential diagnostic role of circulating miRNAs, miR-148a and miR-122-5p, in the pathogenesis of osteoporosis and its association with bone markers, hypercortisolism, and vitamin D deficiency were explored in postmenopausal elderly women with osteoporosis.

METHODS

A total of 120 elderly women aged 50-80 years old were recruited in this study, of which only 100 eligible women with amenorrhea of at least 12 consecutive months or surgical menopause participated in this study. Based upon bone mineral density (BMD) measurements, the participants were classified according into two groups: normal (n = 45; T score of ≥-1.0) and osteoporosis (n = 55; T score: ≤-2.5). Circulating miRNAs, miR-148a and miR-122-5p, were estimated by real-time RT-PCR analysis. In addition, bone markers, hypercortisolism, and vitamin D deficiency were colorimetrically and ELISA immune assay estimated. The potential role of miR-148a, miR-122-5p, cortisol, and vitamin D in the diagnosis of osteoporosis was predicted using the analysis of the respective area under the receiver operating characteristic curve (AUC-ROC).

RESULTS

The expressed level of miR-148a significantly increased and miR-122-5p significantly decreased in the serum of osteoporotic patients compared to healthy controls. In addition, a significant increase in the levels of cortisol, s-BAP, and CTx and significant decrease in the levels of T-BMD, the levels of OC, and s-Ca were also identified. All parameters significantly correlated with fracture risk parameters; BMD, and T score lumbar spine (L2-L4). Thus, the data showed AUC cut off values (miR-148a; 0.876, miR-122-5p; 0.761) were best evaluated for clinical diagnosis of patients with osteoporosis and that AUC cut off values of 0.748 for cortisol and 0.635 for vitamin D were the best cut off values, respectively, reported for the prediction of osteoporosis clinical diagnosis.

CONCLUSION

In this study, expressed miRNAs miR-148a and miR-122-5p and changes in the levels of both cortisol and vitamin D status are significantly associated with bone loss or osteoporosis. Thus, circulation miRNAs alone or in combination with cortisol and vitamin D status might be considered predictable biomarkers in the diagnosis or the pathogenesis of osteoporosis in elderly postmenopausal women; however, more studies are recommended.

Association between vitamin D receptor BsmI, FokI, and Cdx2 polymorphisms and osteoporosis risk: an updated meta-analysis

Background: Many studies have reported the association between vitamin D receptor (VDR) polymorphism and osteoporosis risk. However, their results were conflicting. Six previous meta-analyses have been published to analyze VDR BsmI, FokI, and Cdx2 polymorphisms on osteoporosis risk. However, they did not evaluate the reliability of statistically significant associations. Furthermore, a lot of new articles have been published on these themes, and therefore an updated meta-analysis was performed to further explore these issues.

Objectives: To explore the association between VDR BsmI, FokI, and Cdx2 polymorphisms polymorphisms and osteoporosis risk.

Methods: The odds ratios (ORs) and 95% confidence intervals (95% CIs) were pooled to evaluate the association between VDR BsmI, FokI, and Cdx2 polymorphisms and osteoporosis risk. To evaluate the credibility of statistically significant associations, we applied the false-positive report probabilities (FPRPs) test and the Venice criteria.

Results: Overall, statistically significantly increased osteoporosis risk was found in Indians and women for VDR FokI polymorphism. Statistically significantly decreased osteoporosis risk was found in West Asians for VDR BsmI polymorphism. However, when we performed a sensitivity analysis after excluding low quality and Hardy–Weinberg Disequilibrium (HWD) studies, significantly decreased osteoporosis risk was only found in overall population for VDR BsmI polymorphism. Further, less-credible positive results were identified when we evaluated the credibility of positive results.

Conclusion: These positive findings should be interpreted with caution and indicate that significant association may most likely result from less-credible, rather than from true associations or biological factors on the VDR BsmI and FokI polymorphisms with osteoporosis risk.

Association of IL-6 174G/C (rs1800795) and 572C/G (rs1800796) polymorphisms with risk of osteoporosis: a meta-analysis

Background

Several studies have been performed to investigate association between IL-6 174G/C (rs1800795) and 572C/G (rs1800796) gene polymorphisms and osteoporosis predisposition. However, the results were conflicting. So, we performed a meta-analysis designed to provide more reliable results for the association between IL-6 gene polymorphisms and osteoporosis.

Methods

Studies were searched using PubMed, EMBASE, the Cochrane Library and Wanfang electronic databases. The odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the association between IL-6 174G/C (rs1800795) and 572C/G (rs1800796) gene polymorphisms and osteoporosis risk. The false-positive report probabilities (FPRP) test and the venice criteria were used to assess the credibility of statistically significant associations.

Results

A total of 9 studies with 1891 osteoporosis patients and 2027 healthy controls were included in current meta-analysis. Overall, The IL-6 174G/C (rs1800795) gene polymorphism was insignificantly associated with osteoporosis vulnerability. For IL-6 572C/G (rs1800796), statistically significant elevated osteoporosis vulnerability was found in IL-6 572C/G additive model (OR = 2.25, 95% CI: 1.55–3.26), dominant model (OR = 1.42, 95% CI: 0.78–2.56) and recessive model (OR = 1.96, 95% CI: 1.36–2.83). However, the IL-6 572C/G C allele was found to be associated with reduced susceptibility to osteoporosis (OR = 0.76, 95% CI: 0.56–1.04). When excluding studies that did not conform to HWE, the results did not change significantly. Further, when we evaluated the credibility of the positive results of the current meta-analysis, we identified less credible positive results in IL-6 572C/G recessive and additive model.

Conclusion

In conclusion, IL-6 572C/G GG genotype may be associated with increased risk of osteoporosis.

Relationship of COL9A1 and SOX9 Genes with Genetic Susceptibility of Postmenopausal Osteoporosis

As one of the most common types of osteoporosis, postmenopausal osteoporosis (PMOP) is caused by both genetic and environmental factors. Previous studies have indicated that SOX9 activity is tightly regulated to ensure normal bone mineral density (BMD) in the adult skeleton, and the COL9A1 promoter region can be transactivated by SOX9. In this study, we aimed to investigate the potential association between PMOP and the COL9A1 and SOX9 genes. A total of 10,443 postmenopausal women, including 2288 patients and 3557 controls in the discovery stage and 1566 patients and 3032 controls in the validation stage, were recruited. Forty-three tag SNPs (36 in COL9A1 and 7 in SOX9) were selected for genotyping to evaluate the association of the SOX9 gene with PMOP and BMD. Association and bioinformatics analyses were performed for PMOP. BMD and serum level of SOX9 were also utilized as quantitative phenotypes in further analyses. SNP rs73354570 of SOX9 was significantly associated with PMOP in both discovery stages (OR 1.24 [1.10-1.39], P = 3.56 × 10^-4, χ² = 12.75) and combined samples (OR 1.25 [1.15-1.37], P = 5.25 × 10^-7, χ² = 25.17). Further analyses showed that the SNP was also significantly associated with BMD and serum levels of the SOX9 protein. Our results provide further supportive evidence for the association of the SOX9 gene with PMOP and of the SOX9 gene with the variation of BMD in postmenopausal Han Chinese women. This study supports a role for SOX9 in the etiology of PMOP, adding to the current understanding of the susceptibility of osteoporosis.

Association Between Bat Vitamin D Receptor 3' Haplotypes and Vitamin D Levels at Baseline and a Lower Response After Increased Vitamin D Supplementation and Exposure to Sunlight

Objective: The aim of this study was to evaluate the relationship between vitamin D levels at baseline and after 12 weeks of supplementation/exposure to sunlight and VDR genotypes (BsmI, TaqI and ApaI) and haplotypes in a homogeneous population of postmenopausal women. Methods: We made a prospective study in which 151 women were randomized to two groups: One with 1000 mg of calcium and 800 IU vitamin D supplementation (102 women) and a placebo group with neither calcium or vitamin D supplementation (49 women). The follow-up was from May to September 2012.Vitamin D was determined by chemiluminescent immunoassay. Genotypes were determined using the Sequenomi Plexplatform and haplotypes using PHASE software. Results: Baseline (25 ± 10 ng/mlvs.23 ± 9 ng/ml, p > 0.05) and 12-week (32 ± 8 ng/mlvs.29 ± 10 ng/ml, p > 0.05) vitamin D levels were similar between the two groups. The genetic study was made in the total population. There were no differences in baseline and final levels of vitamin D in terms of genotypes and haplotypes, except for the Bat haplotype, whose baseline values were lower (25OHD: 21 ± 10 ng/mlvs. 21 ± 10 ng/ml, p = 0.038). The rate of nonresponders in this group was 15 % (p = 0.001), compared with 9 %, 2 % and 3 % in the other groups. Conclusions: The Bat haplotype was associated with lower baseline levels of vitamin D and a worse response to supplementation and, therefore, may be a risk factor for vitamin D deficiency.

The genetic association between osteoprotegerin (OPG) gene polymorphisms and bone mineral density (BMD) in postmenopausal women: A meta-analysis

BACKGROUND

Osteoporosis is a common skeletal disorder in eldest people, especially in postmenopausal women. The osteoprotegerin (OPG) gene has been reported to be associated with the BMD and pathogenesis of osteoporosis. However, the results were inconsistent and inconclusive in previous studies.

METHODS

A meta-analysis was performed to investigate the effect of four common OPG gene polymorphisms (A163G, G1181C, T245G, and T950C) on BMD in postmenopausal women.

RESULTS

A total of 23 eligible studies with 12,973 postmenopausal women were enrolled in present study. Individuals who with AA genotype of A163G were found to have slightly higher femoral hip (P = .03, SMD = 0.49, [95% CI] = [0.06, 0.91]) and total hip BMD (P = .002, SMD = -0.25, [95% CI] = [-0.42, -0.09]) than those with AG genotype. Subjects with GG genotype of G1181C was found to have lower BMD than those with CC or GC genotypes in lumbar spine (GG vs GC: P = .0002, SMD = -0.85, [95% CI] = [-1.29, -0.41]; GG vs CC: P = .02, SMD = -0.21, [-0.39, -0.03]) and total hip BMD (GG vs GC: P = .002, SMD = -0.25, [95% CI] = [-0.42, -0.09]; GG vs CC: P = .01, SMD = -0.15, [95% CI] = [-0.26, -0.03]). In addition, the subjects with GC genotype of G1181C was detected to have lower BMD than those with CC genotype in lumbar spine BMD (P < .05). Furthermore, individuals with TT genotype of T950C were shown to have significant lower lumbar spine BMD compared with those with genotype CC in Caucasian (P < .05). The lumbar spine BMD was lower for subjects with TC genotype of T950C than those with CC genotype in both Caucasian and Asian populations (P < .05). In contrast to A163G, G1181C, and T950G, no association was detected between T245G polymorphism and BMD (P > .05).

CONCLUSION

The present meta-analysis demonstrated the OPG A163G, G1181C, and T950G, but not T245G, might influence the BMD in postmenopausal women.

Gene variants of osteoprotegerin, estrogen-, calcitonin- and vitamin D-receptor genes and serum markers of bone metabolism in patients with Gaucher disease type 1

Purpose

Osteopathy/osteoporosis in Gaucher disease type 1 (GD1) shows variable responses to enzyme replacement therapy (ERT); the pathogenesis is incompletely understood. We aimed to investigate the effects of several gene variants on bone mineral density (BMD) and serum markers of bone metabolism in GD1.

Patients and methods

Fifty adult Caucasian patients with GD1/117 controls were genotyped for gene variants in the osteoprotegerin (TNFRSF11B; OPG), estrogen receptor alpha, calcitonin receptor (CALCR), and vitamin D receptor (VDR) genes. In patients and 50 matched healthy controls, we assessed clinical data, serum markers of bone metabolism, and subclinical inflammation. BMD was measured for the first time before/during ERT (median 6.7 years).

Results

Forty-two percent of patients were splenectomized. ERT led to variable improvements in BMD. Distribution of gene variants was comparable between patients/controls. The AA genotype (c.1024+283G>A gene variant; VDR gene) was associated with lower Z scores before ERT vs GA (P=0.033), was encountered in 82.3% of patients with osteoporosis and was more frequent in patients with pathological fractures. Z score increases during ERT were higher in patients with the CC genotype (c.9C>G variant, TNFRSF11B; OPG gene; P=0.003) compared with GC (P=0.003). The CC genotype (c.1340T>C variant, CALCR gene) was associated with higher Z scores before ERT than the TT genotype (P=0.041) and was absent in osteoporosis. Osteocalcin and OPG were lower in patients vs controls; beta crosslaps, interleukin-6, and ferritin were higher.

Conclusions

We suggest for the first time a protective role against osteoporosis in GD1 patients for the CC genotype of the c.9C>G gene variant in the TNFRSFB11 (OPG) gene and for the CC genotype of the c.1340T>C gene variant (CALCR gene), while the AA genotype of the c.1024+283G>A gene variant in the VDR gene appears as a risk factor for lower BMDs. Serum markers suggest decreased osteosynthesis, reduced inhibition of osteoclast activation, increased bone resorption, and subclinical inflammation during ERT.

Association of Vitamin D Receptor (FokI and BsmI) Gene Polymorphism with Bone Mineral Density and Their Effect on 25-Hydroxyvitamin D Level in North Indian Postmenopausal Women with Osteoporosis

Osteoporosis is a systemic disease with a strong genetic component. Vitamin D receptor (VDR) has been suggested as a candidate gene for osteoporosis. Therefore the present study was aimed to investigate the pattern of allelic variants of VDR gene polymorphism (FokI and BsmI), its influence on vitamin D levels and bone mineral density (BMD) in North Indian postmenopausal women with osteoporosis for possible genetic association. 254 postmenopausal osteoporotic women and 254 postmenopausal non osteoporotic women were included in the study. VDR FokI and BsmI gene polymorphism gene were assessed by the PCR-RFLP method. Serum 25-hydroxyvitamin D was measured by the ELISA. BMD at the L1-L4 lumbar spine, hip, forearm and femoral neck was assessed by dual energy X-ray absorptiometry. The average BMD at spine and hip in postmenopausal women with bb and spine, hip, femoral neck and forearm with ff genotype had significantly low BMD. The frequency of ff genotype and f allele was significantly higher in postmenopausal osteoporotic women when compared with postmenopausal non osteoporotic women. However, no significant association was found between the genotypes and vitamin D levels. Our study reveals that VDR gene FokI and BsmI polymorphism is significantly associated with low bone mineral density. Therefore the ff genotype and f allele of VDR FokI gene may be used as an important risk factor for osteoporosis.

Calcitonin Receptor AluI (rs1801197) and Taq1 Calcitonin Genes Polymorphism in 45-and Over 45-year-old Women and their Association with Bone Density

PURPOSE

Calcitonin receptor gene has also a polymorphism which is associated with bone mass density. This study evaluates the association between calcitonin receptor AluI (rs1801197) and Taq1 calcitonin genes polymorphism with bone density rate.

METHODS

In this descriptive-analytical study in 2013 in southwestern Iran, 200 blood samples, per the Cochran sample size formula, were taken from women aged 45 and older. DNA was extracted from the samples using the phenol- chloroform method and the genomic fragments in question were proliferated using the polymerase chain reaction (PCR) method.

RESULTS

The genotypic distribution of polymorphism AluI for TT, TC, and CC genotypes in control group was 31.4%, 38.6%, and 30% and in patients 25.4%, 55.4%, and 19.2%, respectively. There was no significant difference in polymorphism AluI between patients and control group and no significant association was found between this gene and bone density rate (P > 0.05). All patients and the individuals in the control group exhibited tt genotype for TaqI calcitonin gene and no significant association was found between these participants and osteoporosis.

CONCLUSION

There was no association between two polymorphisms and osteoporosis, and between polymorphism of these two genes and osteoporosis development rate in the participants.

Lack of association of vitamin D receptor BsmI gene polymorphism with bone mineral density in Spanish postmenopausal women

Osteoporosis is a polygenic disorder that is determined by the effects of several genes, each with relatively modest effects on bone mass. The aim of this study was to determine whether the vitamin D receptor single nucleotide polymorphism BsmI is associated with bone mineral density (BMD) in Spanish postmenopausal women. A total of 210 unrelated healthy postmenopausal women aged 60 ± 8 years were genotyped using TaqMan^® SNP Genotyping Assays. Lumbar and femoral BMD were determined by dual-energy X-ray absorptiometry (DEXA). Daily calcium and vitamin D intake were determined by a food questionnaire. No differences were found in the femoral neck, trochanter, Ward’s Triangle, L2, L3, L4, L2-L4, or between the femoral neck and total hip BMD after further adjustment for potential confounding factors (P > 0.05) (age, BMI, years since menopause and daily calcium intake). The BsmI polymorphism in the VDR gene was not associated with BMD in Spanish postmenopausal women.

A polymorphism at the translation start site of the vitamin D receptor gene is associated with the response to anti-osteoporotic therapy in postmenopausal women from southern Italy

The present study investigated the effect of two single nucleotide polymorphisms (SNPs) of the vitamin D receptor (VDR) gene, rs1544410 A/G and rs2228570 C/T, in modulating bone mineral density (BMD) and the response to treatment with bisphosphonates or strontium ranelate in postmenopausal osteoporosis (PMO). Four hundred eighteen postmenopausal women from Southern Italy treated with bisphosphonates or strontium ranelate for three years were enrolled and stratified according to their genotype. Changes in BMD were expressed as the delta t-score (Δt-score). Allelic frequencies for rs1544410 A/GSNP were 11.2% AA, 50.0% GA and 38.8% GG; for rs2228570 C/TSNP were 54.8% CC, 39.5% TC and 5.7% TT. TT carriers showed a lower t-score than TC and CC (both p < 0.02) genotypes and were more responsive to the therapy when compared to both TC (p < 0.02) and CC (p < 0.05) carriers. Specifically, TT carriers receiving alendronate demonstrated a significant improvement of the Δt-score compared to TC and CC (both p < 0.0001) carriers. After adjustment for confounders, the Δt-score showed evidence of a statistically significant positive association with TT in all treatments considered. Therapy response was independent of rs1544410 A/G SNP; instead, rs2228570 C/TSNP was associated with a better response to antiresorptive treatment, thus suggesting that the therapy for PMO should be personalized.

Association between calcitonin receptor AluI gene polymorphism and bone mineral density: A meta-analysis

The association between calcitonin receptor (CTR) AluI gene polymorphism and bone mineral density (BMD) remains unclear. In order to elucidate this association, a meta-analysis was performed to provide a comprehensive assessment of the studies carried out to date. PubMed, the Cochrane Library, Web of Science and the China National Knowledge Infrastructure database were searched to identify eligible studies. The data were extracted independently by two authors using a standard form, the studies were meta-analyzed and disagreements were resolved through discussion. Fifteen eligible studies involving 3,093 females and 654 males were included for analysis. Overall, the male subjects with the CC genotype had non-statistically different lumbar spine and femoral neck BMD compared to subjects with the CT/TT and CT genotypes. The BMD of female subjects with the CC genotype was similar to that of patients with the CT or CT/TT genotypes. In Chinese male subjects, those with the CC genotype had almost the same BMD as those with the CT and CT/TT genotypes. The results also demonstrated that Chinese female subjects with the CC genotype had similar BMD at the lumbar spine and femoral neck to subjects with the CT and CT/TT genotypes. Furthermore, Southern Chinese subjects with CC genotypes did not have a different BMD at the lumbar spine and femoral neck compared to patients with CT and CT/TT genotypes. Notably, Northern Chinese subjects with the CC genotype had a higher BMD at the lumbar spine compared to subjects with CT/TT genotypes and a lower BMD at the femoral neck compared to subjects with CT/TT genotypes. Among Northern Chinese females, those with CC genotypes also had a higher BMD at the lumbar spine compared to those with CT/TT genotypes, while no difference was observed in the BMD of the lumbar spine and femoral neck between patients with CC and CT genotypes. In Southern Chinese females, no significant difference was found in the BMD at the lumbar spine and femoral neck between those with CC and those with CT or CT/TT genotypes. In conclusion, the AluI gene polymorphism may have an association with BMD in Northern Chinese subjects and the CC genotype may have a protective effect on spine BMD; however, the CC genotype may be a risk factor for low femoral neck BMD in Northern Chinese subjects. Further studies are required to fully investigate the potential association between AluI gene polymorphism and BMD.

Association between vitamin D receptor gene polymorphisms (Fok1 and Bsm1) and osteoporosis: a systematic review

Osteoporosis is a health concern characterized by reduced bone mineral density (BMD) and increased risk of fragility fractures. Many studies have investigated the association between genetic variants and osteoporosis. Polymorphism and allelic variations in the vitamin D receptor gene (VDR) have been found to be associated with bone mineral density. However, many studies have not been able to find this association. Literature review was conducted in several databases, including MEDLINE/Pubmed, Scopus, EMBASE, Ebsco, Science Citation Index Expanded, Ovid, Google Scholar, Iran Medex, Magiran and Scientific Information Database (SID) for papers published between 2000 and 2013 describing the association between Fok1 and Bsm1 polymorphisms of the VDR gene and osteoporosis risk. The majority of the revealed papers were conducted on postmenopausal women. Also, more than 50% studies reported significant relation between Fok1, Bsm1 and osteoporosis. Larger and more rigorous analytical studies with consideration of gene-gene and gene-environment interactions are needed to further dissect the mechanisms by which VDR polymorphisms influence osteoporosis.

PvuII and XbaI polymorphisms of estrogen receptor-α and the results of estroprogestagen therapy in girls with functional hypothalamic amenorrhea - preliminary study

INTRODUCTION

The aim of this study was the long-term prospective evaluation of the effects of estroprogestagen (EP) therapy on the bone mineral density (BMD) of girls with functional hypothalamic amenorrhea (FHA) carrying various PvuII and XbaI polymorphisms of ER-α.

MATERIAL AND METHODS

Prospective observation included 84 FHA girls and 50 controls. The FHA patients were subjected to 4-year sequential therapy with 17β estradiol (2 mg from the 2(nd) to 25(th) day of the menstrual cycle) and dydrogesterone (10 mg from the 16(th) to the 25(th) day). Hormonal parameters, serum concentration of the bone fraction of alkaline phosphatase (BALP), urine concentration of cross-linked n-telopeptide of type I collagen (Ntx) and BMD were determined before and after the treatment.

RESULTS

Six-month treatment resulted in a marked increase in estradiol (p = 0.001), testosterone and prolactin levels (p = 0.01 both) and a significant decrease in BALP and Ntx (p = 0.001 both). Patients with the PP polymorphism had significantly lower baseline BMD compared to carriers of other polymorphic variants of PvuII (p = 0.003). A significant increase in BMD was observed throughout the entire therapy period, with no significant differences in the yearly dynamics of BMD changes observed amongst various polymorphic variants and haplotypes of ER-α.

CONCLUSIONS

The EP therapy is effective in the treatment of BMD disorders associated with FHA, and treatment results do not depend on PvuII and XbaI polymorphisms of ER-α.

Association between osteoporosis and polymorphisms of the bone Gla protein, estrogen receptor 1, collagen 1-A1 and calcitonin receptor genes in Turkish postmenopausal women

In this study, we have investigated the association between osteoporosis and osteocalcin (BGLAP) -298 C>T, estrogen receptor 1 (ER1) 397 T>C, collagen type1 alpha 1 (Col1A1) 2046 G>T and calcitonin receptor (CALCR) 1340 T>C polymorphisms. Genomic DNA was obtained from 266 persons (158 osteoporotic and 108 healthy controls). Genomic DNA was extracted from EDTA-preserved peripheral venous blood of patients and controls by a salting-out method and analyzed by PCR-RFLP. As a result, there was no statistically significant difference in the genotype and allele frequencies of patients and controls for BGLAP -298 C>T, Col1A1 2046 G>T, ER1 397 T>C and CALCR 1340 T>C polymorphisms. However, ER1 CC genotype compared with TT+TC genotypes was found to increase the two fold the risk of osteoporosis [p=0.039, OR=2.156, 95% CI (1.083-4.293)] and CALCR CC genotype compared with TT+TC genotypes was found to have protective effect against osteoporosis [p=0.045, OR=0.471, 95% CI (0.237-0.9372)]. In the combined genotype analysis, ER1/CALCR TCCC combined genotype was estimated to have protective effect against osteoporosis [p=0.0125, OR=0.323, 95% CI (0.1383-0.755)] whereas BGLAP/Col1A1 CCTT and ER1/CALCR CCTT combined genotypes were estimated as risk factors for osteoporosis in Turkish population (p=0.027, p=0.009 respectively).

Genetic and environmental factors in human osteoporosis

Osteoporosis is a common disorder, with prolongation of the average life span it has become a major public health problem. On the formation of osteoporosis genetic factors and environmental influences could play a role then it is considered as multi-factorial. Because a variety of functions to affect susceptibility to the formation of osteoporosis VDR-F, VDR-B, COL1A1, ESR1X, ESR1P and CTR are thought to be candidate genes. In this study, the aim is to investigate the relationship between these genes polymorphism and bone mineral density (BMD) values of lumbar vertebra and femoral neck in 188 Turkish people. Lumbar spine and femoral neck BMD of the individuals included in the study were measured by the dual X-ray absorptiometry method. The genotyped polymorphisms by simultaneous amplification of five regions of the genome, containing six SNPs of interest and detecting the amplified product, using the kit MetaBone Clinical Arrays(®). Statistical analyses indicated that; VDR-B gene polymorphisms major (P = 0.013), VDR-F polymorphisms have minor (P = 0.082) effect on femur BMD. None of the other genes has any significant effect on spinal BMD. Patient age, body mass index and diet has significant effect on femoral and spinal BMD. Osteoporosis is a multi-factorial disease and many genetic and non-genetic risk factors contribute to the development of osteoporosis. Early detection of a genetic predisposition to osteoporosis should allow delay and/or limit unfavorable changes in the bone tissue.

Association between ER-α polymorphisms and bone mineral density in patients with Turner syndrome subjected to estroprogestagen treatment--a pilot study

Reduced bone mineral density (BMD) is present in many women with Turner syndrome (TS), and hypo-estrogenism is known to play a vital role in bone mineralization disturbances. It has been suggested that genetic factors play an important role in the regulation of BMD. The aim of this study was to analyze the association between Pvu II and XbaI ER-α polymorphisms and BMD in TS patients subjected to estroprogestagen (EP) treatment. Thirty-two TS patients aged 17-38 (mean age 22.7 ± 8.2) along with 82 healthy controls were the subjects for this study. Baseline values of hormonal parameters, BMD and bone density markers were measured in the subjects. Subsequently, TS patients underwent 4 years of EP therapy. The results of laboratory parameters and BMD were analyzed in regard to PvuII and XbaI polymorphic variants of the ER-α gene. The increase in BMD of TS subjects was the highest in the 1st (7.5%, p = 0.013) and 2nd (6.6%, p = 0.008) years of treatment. Four years of EP therapy was reflected by a significant increase in BMD z-scores in patients with xx and Xx genotypes of the XbaI gene and in those with with the pp and Pp genotypes of PvuII. In patients with haplotypes other than XXPP, BMD z-scores were significantly higher compared to their baseline after 2 (p = 0.002), 3 (p < 0.001) and 4 (p < 0.001) years of treatment. In conclusion, genotypes xx and pp were shown to be prognostic markers of a good response to EP treatment, whereas the XXPP haplotype carriers were revealed to have the risk factors for insufficient responsiveness against EP treatment in BMD control.

Genetic analysis of vertebral trabecular bone density and cross-sectional area in older men

We investigated 383 bone candidate genes for associations between single nucleotide polymorphisms and vertebral trabecular volumetric bone mineral density (vBMD) and cross-sectional area (CSA) in 2,018 Caucasian men aged ≥ 65 years. SNPs in TGFBR3, SOST, KL, CALCR, LEP, CSF1R, PTN, GNRH2, FGFR2, and MEPE were associated with vBMD and SNPs in CYP11B1, DVL2, DLX5, WNT4, and PAX7 were associated with CSA in independent study samples (p < 0.005).

INRODUCTION

Vertebral bone mineral density and cross-sectional area are important determinants of vertebral bone strength. Little is known about the specific genetic variants that influence these phenotypes in humans.

METHODS

We investigated the potential genetic variants associated with vertebral trabecular volumetric BMD and CSA measured by quantitative computed tomography. We initially tested for association between these phenotypes and 4608 tagging and potentially functional single nucleotide polymorphisms (SNPs) in 383 candidate genes in 862 community-dwelling Caucasian men aged ≥ 65 years in the Osteoporotic Fractures in Men Study.

RESULTS

SNP associations were then validated by genotyping an additional 1,156 randomly sampled men from the same cohort. We identified 11 SNPs in 10 genes (TGFBR3, SOST, KL, CALCR, LEP, CSF1R, PTN, GNRH2, FGFR2, and MEPE) that were consistently associated with trabecular vBMD and five SNPs in five genes (CYP11B1, DVL2, DLX5, WNT4, and PAX7) that were consistently associated with CSA in both samples (p < 0.005).

CONCLUSION

None of the SNPs associated with trabecular vBMD were associated with CSA. Our findings raise the possibility that at least some of the loci for vertebral trabecular BMD and bone size may be distinct.

Association of estrogen receptor alpha and collagen type I alpha 1 gene polymorphisms with bone mineral density in postmenopausal women

In this study, ERα gene PvuII and XbaI polymorphisms and COL1A1 gene Sp1 polymorphisms in postmenopausal women were compared with lumbar vertebra and femoral neck BMD values. In conclusion, it was designated that PvuII polymorphism was effective on average lumbar vertebra BMD value in postmenopausal women of our study group.

INTRODUCTION

Bone mineral density (BMD), the major determinant of osteoporotic fracture risk, has a strong genetic component. Several candidate gene polymorphisms have been implicated in the regulation of this process. In this study, the relationship among BMD values of lumbar vertebra and femoral neck and ERα gene PvuII and XbaI polymorphisms and COL1A1 gene Sp1 polymorphism in 126 postmenopausal women (30 normal, 46 osteopenic, and 50 osteoporotic in terms of bone mineral density) was researched.

METHODS

The ERα gene PvuII and XbaI genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) whereas the COL1A1 gene Sp1 genotype was determined by real-time PCR. BMDs at the lumbar spine (vertebrae L1-L4) and hip (femur neck) were measured by dual-energy X-ray absorptiometry.

RESULTS

According to our study results, the significant difference was found in women with normal, osteopenic, and osteoporotic bone mass in terms of ERα gene PvuII polymorphism "pp" genotype frequency. The "pp" genotype frequency was significantly lower in women with normal bone mass. Average lumbar vertebra BMD value of women with "PP" genotype was significantly higher than that with "pp" genotype. On the other hand, in the evaluations on ERα gene XbaI polymorphism and COL1A1 gene Sp1 polymorphism, it was noted that there was no difference in terms of average BMD values, genotype, and allele frequencies among groups.

CONCLUSION

In conclusion, it was designated that ERα gene PvuII polymorphism was effective on average lumbar vertebra BMD value in postmenopausal women of our study group.

Genetic predisposition for femoral neck stress fractures in military conscripts

BACKGROUND

Stress fractures are a significant problem among athletes and soldiers and may result in devastating complications or even permanent handicap. Genetic factors may increase the risk, but no major susceptibility genes have been identified. The purpose of this study was to search for possible genetic factors predisposing military conscripts to femoral neck stress fractures.

RESULTS

Eight genes involved in bone metabolism or pathology (COL1A1, COL1A2, OPG, ESR1, VDR, CTR, LRP5, IL-6) were examined in 72 military conscripts with a femoral neck stress fracture and 120 controls. The risk of femoral neck stress fracture was significantly higher in subjects with low weight and body mass index (BMI). An interaction between the CTR (rs1801197) minor allele C and the VDR C-A haplotype was observed, and subjects lacking the C allele in CTR and/or the C-A haplotype in VDR had a 3-fold higher risk of stress fracture than subjects carrying both (OR = 3.22, 95% CI 1.38-7.49, p = 0.007). In addition, the LRP5 haplotype A-G-G-C alone and in combination with the VDR haplotype C-A was associated with stress fractures through reduced body weight and BMI.

CONCLUSIONS

Our findings suggest that genetic factors play a role in the development of stress fractures in individuals subjected to heavy exercise and mechanical loading. The present results can be applied to the design of future studies that will further elucidate the genetics of stress fractures.

Evaluation of the effects of vitamin D receptor and estrogen receptor 1 gene polymorphisms on bone mineral density in postmenopausal women

The aim of this study is to evaluate the effects of estrogen receptor 1 (ESR1) and vitamin D receptor (VDR) gene polymorphisms on bone mineral density (BMD) in a group of previously untreated osteoporotic women. Effects of demographic, environmental, and hormonal factors were also evaluated in this context. Fifty women who did not have a prior diagnosis or treatment of osteoporosis were compared with 50 nonosteoporotic postmenopausal women. Demographic and morphometric characteristics, medical history, dietary habits, exercise history, and sunlight exposure were recorded. The diagnosis of osteoporosis was made with regard to BMD measurements with DEXA. Blood samples were obtained for serum biochemistry, bone turnover markers, and VDR and ESR1 gene polymorphism analysis. Polymorphic sites of VDR and ESR1 genes were amplified by polymerase chain reaction and examined using restriction fragment length polymorphism. Bb genotype was significantly higher in the osteoporotic group when compared to controls (p=0.022). Each 1 U decrease in the body mass index (BMI) increased the risk of osteoporosis by 8% independent of the genotype. We could not observe a significant effect of ESR1 polymorphism on BMD or osteoporosis risk. The interaction of ApaI and BsmI genotypes were found to be significant (p=0.041) and the AaBb genotype, when corrected for BMI, was shown to increase the risk of osteoporosis five times (p=0.005). However, the results demonstrated insignificant p values when correction for multiple testing was performed with the Bonferroni method in the logistic regression model. A predominance of Bb genotype of the VDR gene was evident in this group of postmenopausal Turkish women. Moreover, the combined genotype AaBb conferred a five times increased risk for osteoporosis when corrected for clinical variables.

Fracture, bone mineral density, and the effects of calcitonin receptor gene in postmenopausal Koreans

SUMMARY

In a candidate gene association study, we found that the variations of calcitonin receptor (CALCR) gene were related to the risk of vertebral fracture and increased bone mineral density (BMD).

INTRODUCTION

Calcitonins through calcitonin receptors inhibit osteoclast-mediated bone resorption and modulate calcium ion excretion by the kidney and also prevent vertebral bone loss in early menopause.

METHODS

To identify genetically susceptible factors of osteoporosis, we discovered the variations in CALCR gene, genotyped in Korean postmenopausal women (n = 729), and examined the potential involvement of seven single-nucleotide polymorphism (SNPs) and their haplotypes in linkage disequilibrium block (BL_hts).

RESULTS

The SNPs, +43147G > C (intron 7), +60644C > T (exon13, 3' untranslated region), and their haplotypes, BL2_ht1 and BL2_ht2, showed a significant association with risk of vertebral fracture (p = 0.048-0.004) and BL2_ht1 showed a highly significant protective effect. Moreover, the polymorphism +60644C > T showed a highly significant association with BMD at both lumbar spine and femoral neck. The subjects carrying CC and CT genotypes with the SNP, +60644C > T, had higher BMD values at the lumbar spine (p = 0.01-0.001) and femoral neck (p = 0.025-0.009).

CONCLUSION

These results indicate that the CALCR gene may regulate bone metabolism, and +60644C > T in the CALCR gene may genetically modulate bone phenotype.

Vitamin D receptor gene polymorphism and osteoporosis in the Turkish population

Osteoporosis is one of the most important medical problems facing the aging population. It is defined as a decrease in the bone mass leading to an unacceptably high risk of fractures. Osteoporosis is a multifactorial disease. It is well established that genetic factors are involved in the pathogenesis of osteoporosis. Polymorphism of the vitamin D receptor (VDR) gene has been reported to play a major role in variations for genetic regulation of bone mass. Its role within various ethnic populations is not clear. The purpose of this project was to determine the frequencies of VDR genotypes in Turkey. Three polymorphisms of the VDR gene were analyzed using the polymerase chain reaction-restriction fragment length polymorphism technique. The sample for our study was comprised of postmenopausal women in Turkey, 100 of whom were diagnosed with osteoporosis. They were compared with 146 healthy controls. BsmI genotype frequencies in Turks resemble Caucasians rather than Asians, and Taq genotype frequencies in Turks neither resemble Caucasians nor Asians. The genotype frequencies of VDR were not statistically different between patients with osteoporosis and the control group. Among VDR haplotypes, bbAATT and bbTtAa are more frequent in the osteoporosis group than the control group.

Vitamin-D-Receptor Genotypes and Bone-Mineral Density in Postmenopausal Women: Interaction with Physical Activity

The current study investigated the association between vitamin-D-receptor (VDR) genotypes with bone-mineral density (BMD) and its interaction with physical activity level (PAL). Individuals in a sample of 192 volunteers (67.84 ± 5.23 years) underwent BMD evaluation and were genotyped for VDR ApaI, BsmI, FokI, and TaqI polymorphisms. Haplotypes were reconstructed through expectation-maximization algorithm, and regression-based haplotype-specific association tests were performed with studied phenotypes. None of the polymorphisms were associated with BMD at any site; however, haplotype was associated with femoral-neck and Ward’s-triangle BMD. Interaction between PAL and VDR genotypes was significant for the FokI polymorphism at femoral-neck and Ward’s-triangle BMD. The FokI T/T genotype was associated with higher BMD in active women. It was concluded that VDR haplotypes, but not genotypes, are associated with femoral-neck and Ward’s-triangle BMD in post-menopausal women. Moreover, the results suggest that VDR FokI polymorphism might be a potential determinant of BMD response to physical activity.

Genetic and environmental factors in human osteoporosis from Sub-Saharan to Mediterranean areas

The aim of this study was to determine the prevalence of known gene polymorphisms associated with osteoporosis in postmenopausal normal women from Burkina Faso and Sicily, compared to postmenopausal Sicilian women with osteoporosis, and to establish the weight of environmental factors in the mechanism of osteoporosis. Bone mass density (BMD) was measured by phalangeal quantitative ultrasound (QUS) in Burkinabe woman and by the dual X-ray absorptiometry at the femoral neck in Sicilian women. The polymorphisms of the vitamin D receptor (VDR) gene, estrogen receptor (ESR) gene, calcitonin receptor (CTR) gene and COL1A1 collagen gene were characterized by PCR. The social characteristics of studied women were evaluated by a specific questionnaire. The observed percentages of single specific polymorphisms did not differ from that expected with exception of VDR B allele and ESR X and P allele in Burkinabe and Sicilian women, respectively. Association analyses and multivariate two-step regression model of social and molecular parameters, demonstrated that in comparison to the VDR, ESR, CTR polymorphisms, physical activities and healthy diet, associated with outdoor work are the best favourable prognostic factors for osteoporosis. A diet rich in calcium, other minerals and vitamin D in association with physical activity represents the most effective way to maintain not only a healthy bone structure but also an acceptable BMD. This is particularly true for Sub-Saharan women.

Molecular genetic studies of gene identification for osteoporosis

This review comprehensively summarizes the most important and representative molecular genetics studies of gene identification for osteoporosis published up to the end of September 2007. It is intended to constitute a sequential update of our previously published reviews covering the available data up to the end of 2004. Evidence from candidate gene-association studies, genome-wide linkage and association studies, as well as functional genomic studies (including gene-expression microarray and proteomics) on osteogenesis and osteoporosis, are reviewed separately. Studies of transgenic and knockout mice models relevant to osteoporosis are summarized. The major results of all studies are tabulated for comparison and ease of reference. Comments are made on the most notable findings and representative studies for their potential influence and implications on our present understanding of genetics of osteoporosis. The format adopted by this review should be ideal for accommodating future new advances and studies.

Genotypes and clinical aspects associated with bone mineral density in Argentine postmenopausal women

The aim of this study was to determine genotypes and clinical aspects associated with bone mineral density (BMD) in postmenopausal women from Córdoba, Argentina. Polymorphisms were assessed by RFLP-PCR technique using BsmI and FokI for vitamin D receptor gene (VDR) and XbaI and PvuII for estrogen receptor-alpha gene (ERalpha) as restrictases. Sixty-eight healthy, 54 osteopenic, and 64 osteoporotic postmenopausal women were recruited. Femoral neck and lumbar spine BMD were inversely correlated with age in the entire analyzed population. Height was lower in osteopenic and osteoporotic women as compared to healthy women (P < 0.05). Weight and body mass index (BMI) were the lowest in osteoporotic women (P < 0.01 versus healthy group). Serum procollagen type I Nterminal propeptide (PINP) was higher in osteoporotic women as compared to the other groups. Distribution of VDR and ERalpha genotypes was similar in the three groups. Genotype bb (VDR) was associated with low values of lumbar BMD in the healthy group (P < 0.05 versus genotype Bb), and with low values of femoral BMD (P < 0.05 versus genotype BB) in osteoporotic women. BB*Pp interaction was associated with the highest femoral neck BMD (P < 0.05), whereas the bb*xx interaction was associated with the lowest femoral neck BMD in the total population analyzed (P < 0.05). In conclusion, parameters such as age, height, weight, BMI, serum PINP, VDR genotypes, and interactions between VDR and ERalpha genotypes could be useful to predict a decrease in BMD in Argentine postmenopausal women.

A novel locus on the X chromosome regulates post-maturity bone density changes in mice

Two mouse strains, AKR/J and SAMP6, were assessed longitudinally for bone mineral density of the spine. They displayed very different time courses of bone accrual, with the SAMP6 strain reaching a plateau for vertebral BMD at 3 months, whereas AKR/J mice continued to increase spine BMD for at least 8 months. Among 253 F(2) progeny of an AKR/JxSAMP6 cross, at 4 months of age, the BMD variance was 5-6% of the mean, vs. 15% for weight. Variance increased with age for every parameter measured, and was generally higher among males. The ratio of 6-month/4-month spine BMDs, termed DeltasBMD, had a normal distribution with 5.7% variance, and was largely independent of spine BMD (R=-0.23) or body weight (R=-0.12) at maturity. Heritability of the DeltasBMD trait was calculated at 0.59. Genetic mapping identified two significant loci, both distinct from those observed for BMD at maturity--implying that different genes regulate skeletal growth vs. remodeling. A locus on the X chromosome, replicated in two mouse F(2) populations (P<10(-4) for combined discovery and confirmation), affects age-dependent BMD change for both spine and the full skeleton. Its position agrees with a very narrow region identified by association mapping for effects on lumbar bone density in postmenopausal women [Parsons CA, Mroczkowski HJ, McGuigan FE, Albagha OM, Manolagas S, Reid DM, et al. Interspecies synteny mapping identifies a quantitative trait locus for bone mineral density on human chromosome Xp22. Hum Mol Genet 2005;14:3141-8]. A second locus, on chromosome 7, was observed in only one cross. Single-nucleotide polymorphisms (SNPs) are highly clustered near these loci, distinguishing the parental strains over only limited spans.

Association between an AluI polymorphism in the calcitonin receptor gene and quantitative ultrasound parameters in Korean men

OBJECTIVE

The purpose of this study was to investigate the association between an AluI RFLP of the calcitonin receptor (CTR) gene and quantitative ultrasound (QUS) parameters in Korean men, and the interaction with nutrition as a lifestyle factor.

MATERIALS AND METHODS

Broadband ultrasound attenuation, speed of sound and stiffness index of the calcaneus were measured using an ultrasound bone densitometer in 201 Korean men (mean age +/- SD: 51.6 +/- 11.7 years). The PCR-RFLP method was used to analyze an AluI polymorphism in the CTR gene.

RESULTS

In all subjects, the distribution of CC, CT and TT genotypes occurred with frequencies of 87.1, 12.4 and 0.5%, respectively. When stratified by omnivore and vegetarian groups, there was a significant association between an AluI polymorphism in the CTR gene and QUS parameters such as speed of sound and stiffness index in only vegetarian subjects.

CONCLUSION

Our data suggest that the AluI polymorphism of the CTR gene can be useful as a genetic marker in the interindividual susceptibility of QUS parameters by the interaction with nutritional status as a lifestyle factor.

Gene polymorphisms involved in the regulation of bone quality

Osteoporotic fractures in subjects at advanced age constitute a tremendous and growing problem. Established lifestyle risk factors can explain only a modest proportion of the liability to osteoporotic fractures. Bone mineral density (BMD) is considered the best established risk factor for osteoporotic fractures. The importance of genetic factors in the quality of bone is substantial, but no consensus exists yet on the genes that are involved. However, concomitant diseases, balance disorders and lifestyle habits are more important for fractures in elderly subjects. The abundance of common sequence variations, so-called polymorphisms, in the human genome and their high frequency in the population have made them targets to explain variation in the risk. Some genes have been identified that appear to be involved in the regulation of bone mass and in the pathogenesis of osteoporosis. Among these are those coding for the two estrogen receptors (ERalpha and ERbeta), the androgen receptor (AR) and the vitamin D receptor (VDR). In addition, enzymes involved in the biogenesis of estrone and estradiol have attracted attention as well as polymorphisms in the regulatory region of the type I collagen gene, COLIA1, affecting the binding site for the transcription factor Specificity protein 1 (Sp1). Although evidence suggests that the quality of bone is determined to a large extent by genetic factors, research so far has not been able to unequivocally identify genes involved in this matter. Over the last years a large number of studies have pointed to the variability in many genes and their relation with BMD, bone-related symptoms or specific therapies. The findings emphasize the complexity of the genetics of bone mass and bone loss.