Association of VDR BsmI polymorphism and vitamin D status with osteoarthritis susceptibility.

Environmental and genetic factors are thought to be involved in the pathogenesis of autoimmune thyroid diseases (AITD), which include Graves' disease, Hashimoto's thyroiditis. Polymorphisms of vitamin D receptor (VDR) were implicated in AITDs risk. To date, many studies have evaluated the association between a functional polymorphism in the VDR gene and AITDs risk; however, the result is still ambiguous and inconclusive. To address the association of VDR gene FokI (rs10735810), TaqI (rs731236), BsmI (rs1544410), and ApaI (rs7975232) polymorphisms with AITD risk by meta-analysis. By searching the relevant literature, a total of eight studies were identified and meta-analyzed. HWE for each study are checked. Crude odds ratios (OR) with 95% confidence intervals (CIs) were used to assess the strength of association in the allele polymorphism, codominant model, dominant model, and recessive model. The result indicates that the BsmI or TaqI polymorphisms is significantly associated with AITD risk (OR=0.801 95% CI 0.705, 0.910, Pz=0.001 for B vs. b; OR=0.854, 95% CI 0.757, 0.963, Pz=0.010 for t vs. T), while the ApaI or FokI polymorphism do not. In the subgroup analysis in Europeans, the decreased risk of AITD remained for the B or t variant. This gene-based analysis indicates that, based on current evidence from published studies, the cumulative effect of BsmI or TaqI polymorphisms in VDR is significantly associated with AITD.

Low bone mass and osteopenia have been reported in the axial and peripheral skeleton of adolescent idiopathic scoliosis (AIS) patients. Furthermore, several recent studies have shown that gene polymorphisms are related to osteoporosis. However, no study has yet linked polymorphisms in the vitamin D receptor (VDR) gene and bone mass in AIS. Accordingly, the authors examined the association between bone mass and VDR gene polymorphisms in 198 girls diagnosed with AIS. The VDR BsmI (rs1544410), FokI (rs2228670) and Cdx2 (rs11568820) polymorphisms and bone mineral density at the lumbar spine (LSBMD) and femoral neck (FNBMD) were analyzed and compared to their levels in healthy controls. Mean LSBMD and FNBMD in AIS patients were lower than in age- and sex-matched healthy controls (P = 0.0022 and P = 0.0013, respectively). A comparison of genotype frequencies in AIS patients and controls revealed a significant difference for the BsmI polymorphism only (P = 0.0054). Furthermore, a significant association was found between the VDR BsmI polymorphism and LSBMD. In particular, LSBMD in AIS patients with the AA genotype was found to be significantly lower than in patients with the GA (P < 0.05) or GG (P < 0.01) genotypes. However, no significant association was found between LSBMD or FNBMD and the VDR FokI or Cdx2 polymorphisms. These results suggest that the VDR BsmI polymorphism is associated with LSBMD in girls with AIS.

Associations have been reported between vitamin D receptor (VDR) gene polymorphisms, type 1 diabetes, insulin secretion, and the insulin resistance syndrome. As VDR polymorphisms have no known functional significance, these findings may implicate a variant of the VDR gene or a locus in linkage disequilibrium with the VDR. We have examined VDR mRNA and VDR protein levels in relation to VDR polymorphisms (41 Bangladeshi subjects) and analyzed insulin secretory capacity (143 Bangladeshi subjects), allowing for other known determinants. Peripheral blood mononuclear cells (PBMCs) from subjects who had been genotyped for BsmI, ApaI, TaqI, and FokI VDR restriction fragment length polymorphisms were used for both total VDR mRNA quantitation (using TaqMan) and measurement of VDR protein levels (using a specific micro-immunoassay). Stepwise multiple regression analyses were used (to P < 0.05) to analyze the data. For the insulin secretion index, the best-fit model (n = 143, P < 0.0001) gave age (P = 0.002), TaqI (P < 0.0001), and BMI (P = 0.001) as independent determinants; with the inclusion of VDR mRNA and VDR protein levels, VDR mRNA was the sole independent determinant (n = 41, P = 0.024). However, the best-fit model for VDR mRNA (P = 0.004) gave FokI (P = 0.044) and TaqI (P = 0.04) genotypes and insulin secretory capacity (P = 0.042) as independent determinants. For VDR protein levels, the best-fit model (P = 0.006) gave TaqI genotype (P = 0.005) and circulating 1,25-dihydroxyvitamin-D levels (P = 0.03) as independent determinants. In conclusion, these studies confirm an association between VDR polymorphisms and insulin secretory capacity and demonstrate the VDR genotype to be a significant determinant of VDR mRNA and VDR protein levels in PBMCs, providing functional support to previously described genetic associations with the VDR gene. Furthermore, VDR expression has been shown to be a determinant of insulin secretory capacity.

THU0010 Vitamin d and oestrogen receptor polymorphism in rheumatoid arthritis

Vitamin D receptor homozygote mutant tt and bb are associated with susceptibility to pulmonary tuberculosis in the Iranian population

Background: Vitamin D receptor (VDR) is present on adipocytes, and many studies were performed to investigate the association between polymorphisms in VDR gene with obesity. However, in the Arab Gulf populations, whereas obesity prevalence is increasing dramatically, only a few studies were addressed this relation with obesity based only on body mass index. This study aimed to find the association between three different VDR polymorphisms BsmI (rs1544410), ApaI (rs7975232) and TaqI (rs731236) BsmI, with the adiposity phenotypes (BMI, body fat BF% and waist circumference (WC) as a marker of visceral obesity. Method: In this study, 142 young female subjects from Qatar University were recruited. The study subjects were classified into 88 control subjects (BMI <24.9 kg/m2) with a mean age of 21.65 years and 54 overweight/obese subjects (BMI ≥25 kg/m2) with a mean age of 22.79 years. Blood samples and anthropometric measurements were evaluated. TaqMan assay was used to examine the genotyping of the three SNPs BsmI, ApaI, and TaqI using RT-PCR. In addition, vitamin D and insulin levels were measured using ELISA kits. The adiposity phenotypes were evaluated by anthropometric measurements of body weight, height, waist circumference and BF% were assessed by Body composition analyzer. Results: The results showed that 80.3% of the study subjects were vitamin D insufficient/deficient. The main finding of the current study revealed that the carrier for the minor allele (A) in the BsmI of VDR have significantly higher BMI, WC and BF% values with p-values of 0.009, 0.015 and 0.04, respectively. In addition, it was found that increased WC is associated with lower (suboptimal) vitamin D level with an odds ratio of 3.12 and 95% CI of (1.01-9.63) with a p-value of 0.048. Conclusion: The adiposity phenotype indicators including BMI, WC, and BF% were significantly associated with the minor allele (A) for BsmI (rs1544410); suggesting the possible relation of VDR polymorphism with obesity in Qatar. Vitamin D deficiency could affect the BF% in overweight and obese subjects.

The role of vitamin D in polycystic ovary syndrome

Effect of vitamin D receptor gene polymorphisms on the risk of chronic and aggressive periodontitis: A systematic review and meta-analysis of the Chinese population

PR-6 The conversion of vitamin D to its main biologically active form, 1,25-dihydroxy vitamin D, occurs in the kidney. Since the most biologically active form of vitamin D exerts its activity through binding to the intracellular vitamin D receptor (VDR), most studies of genetic susceptibility have primarily focused on variation within the VDR gene. But, the concert of genes that interact with VDR are vast; therefore, an analysis of genetic variation in VDR and other genes in its pathway may provide insight into the role of vitamin D in renal cell carcinoma (RCC) etiology. In this case-control study, we investigated the relationship between RCC risk and 139 single nucleotide polymorphisms (SNPs) in 8 target genes (VDR, RXRA, RXRB, CYP24A1, GC, STAT1, THRAP4 and TRAP5) of the expanded vitamin D pathway from subjects residing in Central and Eastern Europe. 1,097 RCC cases and 1,476 controls were recruited for this study where genomic DNA was analyzed using an Illumina Oligo Pool-All (OPA) assay. First, the minimum-p-value permutation (Min-P) test was used to identify genes that were associated with RCC risk and that remained significant at a cut off level of 10%. Next, a haplotype-based sliding window analysis of three consecutive SNPs was used to identify chromosome regions of interest that remained significant at a False Discovery Rate (FDR) of 10%. For these regions, haplotype relative risks were computed using the HaploStats package in R. Significant Min-P values were observed for two genes, which were selected for in-depth analysis: VDR (P-value: 0.024) and RXRA (P-value: 0.100). Two chromosomal regions of interest within the VDR gene were identified using the haplotype-based sliding window technique. The first region identified two haplotypes within intron 2, centered around rs4760648, that significantly increased RCC risk (haplotype 1: OR= 1.25; 95% CI= 1.04-1.50 and hapotype 2: OR= 1.26; 95% CI= 1.02-1.54) when compared to patients with the most common referent haplotype. The second signal identified a haplotype (rs886441 and rs12717991) located within intron 4 of the VDR gene that was associated with increased risk among participants with the TG (OR= 1.29; 95%CI= 1.08-1.54) haplotype compared to participants with most common referent haplotype, CA. The global p-values in R for these haplotypes were 0.025 and 0.028, respectively. Across the RXRA gene, a single haplotype located downstream, 3’ of the coding sequence, centered around rs3118523 was shown to increase RCC risk (OR= 1.41; 95% CI= 1.10-1.82) among individuals with the variant haplotype compared to those with the most common haplotype. This is the first study to our knowledge to comprehensively evaluate genetic variation in VDR and other pathway genes in relation to RCC risk. While replication and fine mapping studies will be required to confirm these findings, this study suggests that genes in the vitamin D pathway may modify RCC risk. Citation Information: Cancer Prev Res 2008;1(7 Suppl):PR-6.

Background: Several studies have examined the association between vitamin D receptor (VDR) polymorphisms and osteoporotic fracture risk; however, the results are not uniform. Furthermore, many new articles have been published, and therefore, an updated meta-analysis was performed to further explore these issues. Objectives: The aim of the study was to investigate the association between VDR, BsmI, ApaI, TaqI, FokI, and Cdx2 polymorphisms and osteoporotic fracture risk. Methods: The odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association between VDR BsmI, ApaI, TaqI, FokI, and Cdx2 polymorphisms and the risk of osteoporotic fracture. We also used the false-positive reporting probability (FPRP) test and the Venice criteria to evaluate the credibility of the statistically significant associations. Results: Overall, this study found that the VDR ApaI and BsmI polymorphisms significantly increased the risk of osteoporotic fracture in European countries and America, respectively. However, when sensitivity analysis was performed after excluding low-quality and Hardy–Weinberg disequilibrium (HWD) studies, it was found that only individuals with the double-mutated genotype have an increased risk of osteoporotic fracture in European countries. In addition, when the credibility of the positive results was assessed, it was found that the positive results were not credible. Conclusion: This meta-analysis indicates that there may be no significant association among the polymorphisms of VDR BsmI, ApaI, TaqI, FokI, and Cdx2 and the risk of osteoporotic fracture. The increased risk of osteoporotic fracture is most likely due to false-positive results.

Aim. Vitamin D could have a direct effect on adipocyte differentiation and metabolism and might be involved in glucose regulation of insulin secretion. In recent years several polymorphisms in the gene encoding the vitamin D receptor (VDR), which are potent to alter the activity of VDR protein, have been described. The present study aimed to investigate the prevalence of the VDR BsmI polymorphism and its association with anthropometric and biochemical features of metabolic syndrome in postmenopausal women.Materials and methods. We studied 351 randomly selected healthy postmenopausal women, with mean age of 55.43 ± 2.75 years and mean body mass index (BMI) of 27.5 ± 4.78 kg/m2, to evaluate the frequency of BsmI polymorphism (by restriction fragment length polymorphism–polymerase chain reaction) in the VDR gene and to find out whether there is an association between this polymorphism and BMI, total fat volume and visceral fat (as determined by total body dual-energy X-ray absorptiometry), blood pressure, lipid profile (total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, triglycerides) glucose and fasting insulin in the whole group, as well as subgroups of obese and non-obese women.Results. The prevalence of BsmI genotypes in the study group was 51.0% Bb, 37.3% bb and 11.7% BB. Genotype distribution did not differ from that expected under Hardy–Weinberg equilibrium conditions (χ2 = 2.95, p = 0.22). Apart from LDL-C levels (F = 3.46, p = 0.032), there were no significant differences in anthropometric or metabolic parameters between genotypes.Conclusions. The BsmI polymorphism in the VDR gene does not seem to predispose to obesity and insulin resistance, but the BB genotype is connected with an unfavorable lipid profile.

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.

Background: Vitamin D receptor (VDR) gene polymorphisms are possibly involved in the development of type 2 diabetes mellitus (T2DM). However, the data to date have been inconclusive. Previous studies have suggested an influence of vitamin D receptor alleles on glucose metabolism and on susceptibility to type 2 diabetes mellitus in different ethnic populations through the action of vitamin D endocrine system which related with calcification and lipolysis, insulin secretion, and may be associated with many complicated disease including diabetes. To investigate the relationship between a single nucleotide polymorphism (SNP) of VDR gene and T2DM more studies had been done. However, different results have been found in different spots of the world. Therefore, more studies are needed to understand the variation in these results. This is the first study that shows the implication of the SNP of VDR gene in T2DM in Iraqi patients. Objective: To assess the correlation between serum 25(OH)D3 levels, and vitamin D receptor (VDR) polymorphisms (Fok1, BsmI, TaqI and ApaI), and glycemic control in obese T2DM Iraqi population, this study was performed. Materials and methods: 200 clinically diagnosed T2DM patients, distributed into three subgroups according to therapeutic pattern and 75 healthy controls from the Iraqi population were recruited in this study. The association between the VDR gene SNPs and the T2DM was determined using Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique, and genotype and allele frequencies were calculated between the T2DM and control groups. Results: No significant differences between mean age and the body mass index between both case and control groups were observed. According to current glycemic control consensus, results demonstrated only 20.5 percent of the T2DM patients met this target, which meant that 79.5 percent of the cases were suffering from poor glycemic control 25(OH)D3 levels were significantly lower in the T2DM patients than in the control group, being 17.49 ± 1.12 ng/ml and 31.26 ± 1.25 ng/ml, in the patient and control groups, respectively (p 20 < 30 ng/ml (chi-squared test, p<0.0001). The gene polymorphism analysis for T2DM showed that genotype and alleles frequencies for the VDR genes were in agreement with Hardy–Weinberg equilibrium in all cases. Conclusion: VDR gene polymorphism analysis revealed that neither genotypes nor alleles of VDR BsmI, ApaI showed a significant variation between T2DM patients and controls. In contrast‚ the FF genotype of VDR FokI and TT genotype of VDR TaqI showed a significant (P<0.0001) increase in T2DM patients in comparison to controls. FF and TT homozygotes had significantly higher baseline fasting glucose and HOMI-IR levels than f allele carriers. In addition, data found significantly elevated interlukin IL-6, TNF-α, IL -1β and decreased osteocalcin in association with the Taq1 polymorphism.

Background. To explore the potential role of natural-resistance-associated macrophage protein 1 (NRAMP1) gene, vitamin D receptor (VDR) gene, (human leukocyte antigen, (HLA-DRB1) HLA) -DRB1 gene, and HLA-DQB1 gene polymorphisms in susceptibility to tuberculosis (TB) in the Chinese Kazakh population. Methods. A case-control study was performed on the Chinese Kazak population. Genetic polymorphisms of NRAMP1 gene (3′UTR) and VDR gene (TaqI and FokI) were analysed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing analysis in TB patients and healthy controls. Genetic polymorphisms of HLA-DRB1 gene and HLA-DQB1 gene in the two groups were detected with polymerase chain reaction-sequence-specific primers (PCR-SSPs) technique and sequencing analysis. Results. There was statistically significant difference in the 3′UTR polymorphism between the TB patients and healthy controls in the Chinese Kazak population (P = 0.002; OR = 1.859; 95% CI = 1.182–2.926). Significant difference was observed in the FokI polymorphism between the TB patients and healthy controls (P = 0.001; OR = 1.530; 95% CI = 1.007–2.325). It does not disclose any significant association between the disease and TaqI (P > 0.05). Alleles HLA-DRB1∗04 and HLA-DQB1∗0201 occurred more frequently in patients than in controls (P = 0.011 and 0.002; OR = 1.889 and 1.802; 95% CI = 1.153–3.095 and 1.230–2.639, resp.). Conclusions. Polymorphisms in the NRAMP1 gene, VDR gene, HLA-DRB1 gene, and HLA-DQB1 gene are statistically associated with susceptibility to TB in the Chinese Kazakh population.

Vitamin D receptor polymorphisms and Parkinson’s disease in a Korean population: Revisited