Genetic predictors of skeletal outcomes in healthy fertile women: the Bonturno study

Polymorphisms of FDPS, LRP5, SOST and VKORC1 genes and their relation with osteoporosis in postmenopausal Romanian women

OBJECTIVES

This study aimed to assess the relationship between bone mineral density and genotypes of four polymorphisms in previously detected osteoporosis-candidate genes (FDPS rs2297480, LRP5 rs3736228, SOST rs1234612, VKORC1 rs9934438) in postmenopausal Romanian women with primary osteoporosis.

METHODS

An analytical, prospective, transversal, observational, case-control study on 364 postmenopausal Romanian women was carried out between June 2016 and August 2017 in Cluj Napoca, Romania. Clinical data and blood samples were collected from all study participants. Four polymorphisms were genotyped using TaqMan SNP Genotyping assays, run on a QuantStudio 3 real-time PCR machine.

RESULTS

Women with TT genotype in FDPS rs2297480 had significantly lower bone mineral density values in the lumbar spine and total hip, and the presence of the T allele was significantly associated with the osteoporosis. Women carrying the CC genotype in LRP5 rs3736228 tend to have lower bone mineral density values in the femoral neck and total hip. No significant association was found for the genotypes of SOST rs1234612 or VKORC1 rs9934438.

CONCLUSIONS

Our study showed a strong association between bone mineral density and polymorphisms in the FDPS gene, and a borderline association with LRP5 and SOST polymorphisms in postmenopausal Romanian women with osteoporosis. No association was found for VKORC1.

LRP5 gene polymorphisms and radiographic joint damage in rheumatoid arthritis patients

Rheumatoid arthritis (RA) is characterized by increased bone resorption and impaired bone formation. Osteoblast function is regulated by the canonical LRP5/Wnt/β-catenin pathway. Bone mineral density and RA joint destruction are partially inherited. In line with this, we found significant associations between LRP5 SNPs (p.A1330V, p.N740N, p.V667M) and RA radiographic damage severity.

INTRODUCTION

Increased bone resorption and impaired bone formation characterize rheumatoid arthritis (RA). Canonical Wnt/β-catenin pathway, signalled by lipoprotein receptor-related protein-5 (LRP5), regulates osteoblast function. Since bone mineral density (BMD) and RA joint destruction are partially inherited, we studied their association with LRP5 single nucleotide polymorphisms (SNPs).

METHODS

Clinical data and peripheral blood for biomarkers assessment and LRP5 genotyping were collected from 208 RA patients. Hands and feet X-rays were scored [modified Sharp/van der Heijde Score (SHS), joint space narrowing (JSN), and erosion scores]. Lumbar spine, total left proximal femur, and left hand BMD were assessed by dual-energy X-ray absorptiometry (DXA).

RESULTS

TT genotypes for p.A1330V and p.N740N LRP5 SNPs associated with total SHS, erosion score, and hands erosion score; the same for p.A1330V with feet JSN score and p.N740N with hands total score. AG genotype for p.V667M associated with sclerostin and hands JSN score. Femoral BMD associated with TC genotype for p.N740N. Multiple test correction precluded a few of these associations. Among V667M-N740N-A1330V haplotypes: GTT associated with higher feet JSN score (OR = 3.80; p = 0.016) and ATT with higher JSN score (OR = 4.60; p = 0.032), hands total score (OR = 5.65; p = 0.022), and total SHS (OR = 6.74; p = 0.024).

CONCLUSION

Significant associations between LRP5 SNPs (p.A1330V, p.N740N, and p.V667M) and the severity of radiographic damage reinforce the evidence of bone destruction heritability in RA.

Two novel susceptibility loci for non-small cell lung cancer map to low-density lipoprotein receptor-related protein 5

This study investigated the effect of single-nucleotide polymorphisms (SNPs) of low-density lipoprotein receptor-related protein 5 (LRP5) on the risk of developing non-small cell lung cancer (NSCLC). A total of 500 NSCLC patients and 500 healthy controls were recruited for genotyping of 11 SNPs of LRP5. The association between genotype and NSCLC risk was evaluated by computing the odds ratio (OR) and 95% confidence interval (CI) from multivariate unconditional logistic regression analyses. Eleven Tag SNPs were detected. The frequency of the LRP5 rs3736228 T allele (18.9% in male NSCLC cases and 23.9% in male controls) was statistically different between male NSCLCs and male controls (P=0.03), and the T allele was associated with a lower risk of NSCLC (OR=0.74; 95% CI, 0.56–0.67), whereas the C/C homozygous genotype and the LRP5 rs64843 T/T genotype were associated with an increased risk of NSCLC and squamous cell carcinoma (SCC), respectively (OR=1.43 and 1.77, respectively). Using Haploview software, the frequency of the haplotypes of rs312009/rs3120015/rs3120014 CCC was was significantly higher in female SCC cases compared with female controls (0.064 vs. 0.009, P=0.04). LRP5 rs3736228 and rs64843 SNPs were significantly associated with an increased risk of NSCLC and SCC, respectively. Further studies are required to investigate the functional changes in LRP5 expression and activity in NSCLC in vitro.

Genetic analysis of the relationship between bone mineral density and low-density lipoprotein receptor-related protein 5 gene polymorphisms

Background

A number of studies have examined the association between the polymorphisms of the low-density lipoprotein receptor-related protein 5 gene (LRP5), but previous results have been inconclusive. Thus we performed a meta-analysis of studies on the association between the LRP5 polymorphisms and bone mineral density (BMD) to assess their pooled effects.

Methods

Published literature from PubMed, EMBASE and ISI web of science were searched for eligible publications. Weighted mean difference (WMD) and 95% confidence interval (CI) was calculated using fixed- or random-effects model.

Results

A total of 19 studies with 25773 subjects were considered in this meta-analysis. Of them, 17 examined the association between the A1330V polymorphism and BMD, 8 were focused on the V667M polymorphism, and 2 analyzed the Q89R polymorphism. Individuals with the A1330V AA genotype showed significantly higher BMD than those with the AV/VV genotypes [at lumbar spine (LS): WMD = 0.02g/cm², 95% CI = 0.01-0.03, P < 10^-4; at femur neck (FN): WMD = 0.01g/cm², 95% CI = 0.00-0.02, P = 0.01] or VV genotype (at LS: WMD = 0.02g/cm², 95% CI = 0.01-0.04, P = 0.01). Significant associations were also detected in the analysis for V667M (VV vs. VM/MM: WMD at LS = 0.02g/cm², 95% CI = 0.02-0.03, P < 10^-5; WMD at FN = 0.01g/cm², 95% CI = 0.01-0.02, P = 0.0002). As for Q89R, subjects with the QQ genotype tended to have higher BMD than those with the QR/RR genotypes at FN (WMD = 0.03g/cm², 95% CI = 0.01-0.05, P = 0.005).

Conclusion

This meta-analysis demonstrated that the LRP5 polymorphisms may be modestly associated with BMD of LS and FN.

Association between estrogen receptor α gene (ESR1) PvuII (C/T) and XbaI (A/G) polymorphisms and hip fracture risk: evidence from a meta-analysis

Background and Objective

Genetic factors are important in the pathogenesis of fractures. Notably, estrogen receptor α (ESR1) has been suggested as a possible candidate gene for hip fractures; however, published studies of ESR1 gene polymorphisms have been hampered by small sample sizes and inconclusive or ambiguous results. The aim of this meta-analysis is to investigate the associations between two novel common ESR1 polymorphisms (intron 1 polymorphisms PvuII-rs2234693: C>T and XbaI-rs9340799: A>G) and hip fracture.

Methods

Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of the association.

Results

Five case-control and three cohort studies were assessed, including a total of 1,838 hip fracture cases and 14,972 healthy controls. This meta-analysis revealed that the PvuII T allele is a highly significant risk factor for hip fracture susceptibility, with an effect magnitude similar in male and pre-menopausal and post-menopausal female patients. In stratified analysis based on ethnicity, the PvuII T allele remained significantly correlated with increased risk of hip fracture in Caucasian populations; this correlation, however, was not found in Asian populations. Unlike the PvuII polymorphism, we did not find significant differences in the XbaI (A>G) polymorphism allele or genotype distributions of hip fracture patients and controls. We also found no obvious association between the XbaI polymorphism and hip fracture in any of the racial or gender subgroups.

Conclusion

Our findings show that the ESR1 PvuII T allele may increase the risk of hip fracture and that the XbaI polymorphism is not associated with hip fracture.