Polymorphism rs2073618 of the TNFRSF11B (OPG) Gene and Bone Mineral Density in Mexican Women with Rheumatoid Arthritis

Association between OPG polymorphisms and osteoporosis risk: An updated meta-analysis

Background: Numerous studies have demonstrated an association between osteoprotegerin (OPG) polymorphisms (A163G (rs3102735), T245G (rs3134069), T950C (rs2073617), G1181C (rs2073618)) and osteoporosis risk. However, their conclusions are inconsistent. In addition, some new studies have been updated, and more importantly, previous meta-analyses have not tested for false-positive results. In order to further explore these associations, we recently conducted a meta-analysis. Objectives: To study the relationship between OPG polymorphisms A163G, T245G, T950C, G1181C and the risk of osteoporosis. Methods: PubMed, Medline, International Statistical Institute (ISI), China National Knowledge Infrastructure (CNKI) and China Wanfang Database were used for research searches. Associations were assessed with five genetic models using odds ratios (ORs) with 95% confidence intervals (CIs). In addition, confidence in statistically significant associations was assessed using false-positive report probability (FPRP), Bayesian probability of False discovery (BFDP), and Venice criteria. Results: On the whole, the OPG A163G polymorphism was not significantly associated with risk of osteoporosis. However, in a subgroup analysis, we found that the OPG A163G polymorphism increased the risk of osteoporosis in Caucasians (AG + GG vs AA: OR = 1.35, 95% CI = 1.06-1.73; AA + GG vs AG: OR = 0.64, 95% CI = 0.49-0.82) and the female (G vs A: OR = 1.30, 95% CI = 1.03-1.64; AG + GG vs AA: OR = 1.42, 95% CI = 1.18-1.71). At the same time, the OPG G1181C polymorphism reduces the risk of osteoporosis (C vs G: OR = 0.84, 95% CI = 0.74-0.95; CC vs GG: OR = 0.75, 95% CI = 0.60-0.93; GC + CC vs GG: OR = 0.80, 95% CI = 0.67-0.95; CC vs GG + GC: OR = 0.84, 95% CI = 0.70-1.00). Moreover, a significantly decreased risk of osteoporosis was also discovered in Asian (C vs G: OR = 0.80, 95% CI = 0.66-0.98; CC vs GG: OR = 0.67, 95% CI = 0.47-0.95; GC + CC vs GG: OR = 0.74, 95% CI = 0.58-0.95) and the female (C vs G: OR = 0.85, 95% CI = 0.75-0.97; CC vs GG: OR = 0.77, 95% CI = 0.61-0.96; GC + CC vs GG: OR = 0.79, 95% CI = 0.66-0.95). Finally, we did not find a close association between OPG T245G and T950C polymorphisms and osteoporosis risk. However, when we retained only studies in the control group that was consistent with Hardy-Weinberg equilibrium (HWE) and high-quality scores, we observed that the OPG A163G polymorphism increased the risk of osteoporosis in the overall analysis (G vs A: OR = 1.40, 95% CI = 1.16-1.68; GG vs AA: OR = 1.96, 95% CI = 1.20-3.21; AG + GG vs AA: OR = 1.45, 95% CI = 1.22-1.72). Finally, after the credibility assessment, we concluded that all statistically significant association results in the meta-analysis in this study and those in the previous study were 'positive results with low confidence'. Conclusion: In conclusion, our study concluded that all meaningful results between OPG A163G and G1181C polymorphisms and osteoporosis risk were false-positive results rather than true associations.

Association between Polymorphisms in the IL-1β, TNFRSF11B, CASP1, and IL-6 Genes and Orthodontic-Induced External Apical Root Resorption

Orthodontic-induced external apical root resorption (EARR) is a severe condition affecting the roots of the teeth, whose genetic causes have been inconclusive to date. The aim of the present study was to assess the influence of selected single nucleotide polymorphisms (SNPs) IL-1β, TNFRSF11B, CASP1, and IL-6 genes on post-orthodontic EARR. A sample of 101 patients with clearly assessable orthopantomograms and lateral cephalometric radiographs taken before and at the end of the orthodontic treatment was used to evaluate the presence of EARR. The association between genetic polymorphisms and EARR was assessed with the Chi² test. A binary logistic multi-level model was built to evaluate the ability of patient- and tooth-level variables to predict EARR occurrence. The overall prevalence of EARR resulted to be around 40%. Within the limitations of this study, a significant association was found between EARR presence and the SNP for the IL-1β gene but not for the TNFRSF11B, CASP1, and the IL-6 genes. The final multi-level model demonstrated that the SNP for the IL-1β gene increases the odds of developing EARR by around four times. Since there is currently no accurate method to determine which patients will develop EARR prior to orthodontic treatment, further studies are needed to investigate the predictive ability of further genetic variants on EARR development.

Common Variants of the OPG gene Are Associated with Osteoporosis Risk: A Meta-Analysis

Background: The RANKL/RANK/OPG signaling pathway plays a critical role in osteoclastogenesis and bone remodeling. The associations between sequence variants of the osteoprotegerin (OPG) gene and osteoporosis risk have been widely investigated but remain inconclusive. Objective: We performed a meta-analysis to evaluate the associations between OPG gene variants and osteoporosis risk. Methods: We searched electronic databases and included studies meeting inclusion criteria. The genetic associations of four common OPG variants, A163G, T245G, T950C, and G1181C, with osteoporosis risk were explored. Pooled odds ratios (OR) and 95% confidence intervals (95% CI) were calculated for multiple genetic models. Subgroup analyses including ethnicity, gender, menopausal status, sample size, and control source were also performed. Results: Twenty-six studies comprising 4879 osteoporosis cases and 5708 controls were included. The A163G variant was found to be significantly associated with an increased risk of osteoporosis under both the allelic (G vs. A: OR = 1.45, 95% CI 1.29-1.64, p < 0.001) and dominant models (GG+GA vs. AA: OR = 1.48, 95% CI 1.29-1.70, p < 0.001). Significant associations were also found between the T245G variant and osteoporosis risk. In addition, we observed a reduced risk of osteoporosis in women with the CC genotype at T950C (OR = 0.76, 95% CI 0.64-0.89, p = 0.001) and among Caucasians with the GG or CG genotypes at the G1181C locus (OR = 0.78, 95% CI 0.64-0.94, p = 0.010). In postmenopausal women, only the GG/GA genotypes at the A163G variant were more predisposed to osteoporosis (OR = 1.31, 95% CI 1.00-1.71), whereas CC/CG carriers of G1181C locus may have reduced risk (OR = 0.83, 95% CI 0.66-1.03). Conclusions: Common variants of the OPG gene are associated with osteoporosis risk, especially in the Caucasian population and in the female subgroup. These genetic markers could potentially be used as predictive markers for osteoporosis.

Rheumatoid arthritis and osteoporosis: a bi-directional Mendelian randomization study

Many observation studies have demonstrated a close relationship between rheumatoid arthritis (RA) and osteoporosis (OP). However, the causal genetic correlation between RA and OP remains unclear. In this study, we performed bi-directional Mendelian randomization (MR) analyses to explore causal inference between these two traits. The instrumental variables for RA were selected from a large-scale genome-wide association study (GWAS) (1,523 cases and 461,487 controls). Bone mineral density (BMD) at five different sites (heel (n=265,627), forearm (FA) (n=8,143), femoral neck (FN) (n=32,735), lumbar spine (LS) (n=28,498), and total body (n=28,498)) were used as phenotypes for OP. The inverse variance weighted (IVW) method did not detect any causal effect of BMDs on RA except heel BMD (beta = -7.57 × 10-4, p = 0.02). However, other methods (MR-Egger, weighted median, weighted mode, MR-PRESSO, and MR-RAPS) showed no causal association between heel BMD and RA. Likewise, we did not find a causal effect of RA on BMD at any sites. In conclusion, we found no evidence that RA is causally associated with OP/BMD, or vice versa. We suggested that the associations found in previous observational studies between RA and OP/BMD are possibly related to secondary effects such as antirheumatic treatment and reduced physical activity.

Osteoprotegerin gene polymorphisms and otosclerosis: an additional genetic association study, multilocus interaction and meta-analysis

BACKGROUND

Otosclerosis (OTSC) is among the most common causes of a late-onset hearing loss in adults and is characterized by an abnormal bone growth in the otic capsule. Alteration in the osteoprotegerin (OPG) expression has been suggested in the implication of OTSC pathogenesis.

METHODS

A case-control association study of rs2228568, rs7844539, rs3102734 and rs2073618 single nucleotide polymorphisms (SNPs) in the OPG gene was performed in a Tunisian-North African population composed of 183 unrelated OTSC patients and 177 healthy subjects. In addition, a multilocus association and a meta-analysis of existing studies were conducted.

RESULTS

Rs3102734 (p = 0.013) and rs2073618 (p = 0.007) were significantly associated with OTSC, which were predominantly detected in females after multiple corrections. Among the OPG studied SNPs, the haplotypes A-A-C-G (p = 0.0001) and A-A-C-C (p = 0.0004) were significantly associated with OTSC in females. Multilocus association revealed that the SNPs: rs2073618 in OPG, rs1800472 in TGFβ1, rs39335, rs39350 and rs39374 in RELN, and rs494252 in chromosome 11 showed significant OTSC-associated alleles in Tunisian individuals. In addition, meta-analysis of the rs2073618 SNP in Tunisian, Indian and Italian populations revealed evidence of an association with OTSC (OR of 0.826, 95% CI [0.691-0.987], p = 0.035).

CONCLUSIONS

Our findings suggest that rs3102734 and rs2073618 variants are associated with OTSC in North African ethnic Tunisian population. Meta-analysis of the rs2073618 in three different ethnic population groups indicated an association with OTSC.

Influence of single nucleotide polymorphisms (SNPs) in genetic susceptibility towards periprosthetic osteolysis

Wear debris-induced inflammatory osteolysis remains a significant limiting factor for implant replacement surgeries. Hence, a comprehensive understanding of the complex network of cellular and molecular signals leading to these inflammatory responses is required. Both macrophages and monocytes have a critical role in the instigation of the inflammatory reaction to wear debris but differ in the extent to which they induce cytokine expression in patients. Lately, single nucleotide polymorphisms (SNPs) have been associated with genetic susceptibility among individual patients with implant failure. Studies have shown that SNPs in key pro-inflammatory cytokines and their receptors are associated with osteolytic susceptibility. Likewise, SNPs within several genes involved in the regulation of bone turnover have also been found to be associated with wear debris induced osteolysis. It is presumed that SNP variance might play a decisive role in the activation and signaling of macrophages, osteoblasts, chondrocytes, fibroblasts and other cells involved in inflammatory bone loss. Understanding the extent to which SNPs exist among genes that are responsible for inflammatory bone loss may provide potential targets for developing future therapeutic interventions. Herein, we attempt to summarize the various susceptible genes with possible SNP variance that could contribute to the severity of periprosthetic osteolysis in patients with implants.