Vitamin D Receptor Single Nucleotide Polymorphisms Research Articles

P1308 The ApaI polymorphism in the vitamin D receptor (VDR) gene affects the phenotype and complications of Crohn’s disease

Abstract Background Vitamin D, through its receptor (VDR), exerts pleiotropic effects that support gut barrier homeostasis. Dysregulation of the vitamin D/VDR signaling is implicated in the pathogenesis of inflammatory bowel disease (IBD).1,2 Our study aims to elucidate how the ApaI, BsmI, TaqI, and FokI single-nucleotide polymorphisms (SNPs) influence disease phenotype and the development of related outcomes. Methods In this observational study, 76 patients with Crohn’s disease (CD) and 68 with ulcerative colitis (UC) were consecutively enrolled. Blood samples were collected, and genomic DNA was extracted. VDR SNPs were genotyped via predesigned TaqMan SNP assays on a Step One Plus PCR system. Fisher’s exact test was used for contingency table analysis. A multivariate logistic regression with backward selection evaluated adverse outcome risk, including variables with p<0.05 from univariate analysis. Results Genotype frequencies for all SNPs were in Hardy-Weinberg equilibrium, with no differences observed in distribution between CD and UC groups. The AA genotype of ApaI was accompanied by higher rates of penetrating (B3) disease in CD (36.7% vs. 8.7%; p=0.006) compared to the Aa/aa genotypes. Conversely, Aa/aa genotype carriers were more likely to develop stenotic (B2) CD (67.4% vs. 40%; p=0.032). The FokI SNP was associated with disease location, with the ff genotype being more common among patients with upper GI involvement (L4) (44.4% vs. 10.4%; p=0.022) and colonic disease (23.8% vs. 2.9%; p=0.018) compared to the FF/Ff genotypes. Additionally, patients harboring the f allele (Ff/ff) experienced higher rates of steroid-refractory or steroid-dependent CD (35.5% vs. 12.9%; p=0.035). In the overall cohort, the AA/Aa genotypes were also linked to failure to respond to steroids (37.6% vs. 11.1%; p=0.011). In CD, the risk of IBD-related hospitalization and surgery was significantly higher in patients homozygous for the dominant ApaI and TaqI SNPs than in those carrying the corresponding recessive alleles. Patients with the AA genotype demonstrated the highest surgery rates, followed by those with the Aa/aa genotype (56.7% vs. 23.9%; p=0.007) and then the aa genotype (56.7% vs. 7.1%; p=0.003), suggesting a possible additive effect of the ApaI SNP. In multivariate analysis, the aa genotype showed a protective effect against hospitalization (aOR=0.17; p=0.013), whereas the TT genotype was identified as an independent risk factor for hospitalization (aOR=4.79; p=0.044). Moreover, the aa genotype was independently associated with a decreased risk of IBD-related surgery (aOR=0.055; p= 0.014). Conclusion VDR SNPs, particularly ApaI, influence disease phenotype, progression, and treatment response in CD.

Association of vitamin D receptor gene polymorphisms with caries risk in children: a systematic review and meta-analysis

BackgroundTo investigate the association of vitamin D receptor (VDR) gene polymorphism with caries risk in children(< 18 years).MethodsThe electronic databases PubMed, Cochrane, EMBASE, Web of Science, CNKI, Cqvip, and Wanfang were searched for observational studies on the relationship between VDR single nucleotide polymorphism(SNP) and caries, including cohort, case–control, and cross-sectional studies. Quality assessment of selected studies was conducted using the Newcastle Ottawa scale. Odds ratios (OR) with 95% confidence intervals (CI) values for associations of individual VDR SNP with dental caries were calculated based on four genetic models: allelic, recessive, dominant, and over-dominant.ResultsOf 79 studies considered, 10 (nine case–control and one cross-sectional) were selected for analysis; the studies involved seven VDR SNPs: ApaI(rs7975232),BsmI(rs1544410),FokI(rs2228570),TaqI(rs731236), TaqI/BglI(rs739837), FokI(rs10735810) and Cdx-2(rs11568820). Alleles C and T of FokI(rs10735810) were significantly differently distributed in the caries and caries-free groups (OR = 1.33, 95% CI: 1.30–2.30, P = 0.03), with CC + CT genotypes at this locus associated with greater risk of developing caries than the TT genotype (OR = 1.87, 95%CI: 1.15–3.04, P = 0.01). Further, TT + CC genotype at TaqI(rs731236) was associated with a 1.33-fold higher risk of caries development than the TC genotype (OR = 1.33, 95%CI: 1.06–1.67, P = 0.02). On subgroup analysis, the association between TaqI(rs731236) and caries risk was affected by dentition type, and ethnicity (permanent dentition: OR = 1.48, 95%CI: 1.07–2.03, P = 0.02; Asian: OR = 1.38, 95%CI: 1.02–1.87, P = 0.03;). Genotype distributions at BsmI(rs1544410), TaqI/BglI(rs739837), FokI(rs2228570), and ApaI(rs7975232) did not differ significantly between the caries and caries-free groups.ConclusionsCaries risk could be associated with TaqI(rs731236) and FokI(rs10735810) genotypes, and TaqI(rs731236) may be a risk factor for permanent teeth caries among Asian people.

Relation of T Cell Profile with Vitamin D Receptor and Vitamin D-Binding Protein Gene Polymorphisms in Atopy.

Atopic diseases, including atopic dermatitis (AD) and allergic asthma (AA), are characterized by complex immune responses involving various T cells subsets and their cytokine profiles. It is assumed that single nucleotide polymorphisms (SNPs) in the Vitamin D receptor (VDR) gene and the Vitamin D-binding protein (GC) gene are related to the action of Vitamin D and, consequently, play a role in regulating the immune response. However, there is not enough data to unequivocally support the hypothesis about the relationship between T cells profile and VDR or GC SNPs. Two hundred sixty-six subjects (aged > 18 years) were involved in the study: 100 patients with mild or moderate AD, 85 patients with mild or moderate AA, and 81 healthy individuals. Blood cell counts were determined by standard methods. Flow cytometric analysis was used to evaluate CD4+ T-helper (Th) cell subtypes: Th2, Th1, Th17, and T regulatory (Treg) cells in peripheral blood. Measurements of cytokines, total immunoglobulin E (IgE), and Vitamin D levels in serum were evaluated by ELISA. Significantly higher levels of Th1, Th2, and Th17 cells, along with lower levels of Tregs, were found in patients with atopic diseases compared to healthy individuals. Additionally, higher serum levels of interleukin (IL) 5, IL-17A, and transforming growth factor-β1 (TGF-β1), as well as lower levels of IL-10, were observed in patients with atopic diseases than in control. The study established associations between VDR SNPs and immune profiles: the AA genotype of rs731236 was associated with increased Th2 and Th17 cells and a higher Th1/Th2 ratio; the GG genotype of rs731236 was linked to decreased serum IL-10 and TGF-β1 levels; and the TT genotype of rs11168293 was associated with increased IL-10 levels. Additionally, the GG genotype of GC gene SNP rs4588 was associated with reduced Th2 and Th17 lymphocytes, while the TT genotype of rs4588 was linked to decreased IL-10 levels. Furthermore, the CC genotype of rs7041 was associated with higher levels of Th2, Th17, IL-10, and IL-35, as well as reduced levels of TGF-β1, while the GG genotype of rs3733359 was associated with reduced IL-10 levels. In conclusion, our study demonstrates that the Vitamin D receptor gene single nucleotide polymorphisms rs731236 and rs11168293, along with polymorphisms in the Vitamin D-binding protein gene (rs4588, rs7041, rs3733359), are significantly associated with variations in T cell profiles in atopy. These variations may play a crucial role in promoting inflammation and provide insight into the genetic factors contributing to the pathogenesis of atopy.

VDR Gene Polymorphisms (BsmI, FokI, TaqI, ApaI) in Total Hip Arthroplasty Outcome Patients.

A total hip arthroplasty (THA) can improve quality of life, but loosening of the hip prosthesis is a complex problem in which vitamin D may also play a role. The Vitamin D Receptor (VDR) is involved in the response of cells to the action of vitamin D, and its genetic variability raises the question of whether individual differences could influence the risk of prosthesis loosening. The aim of this study was to investigate the relationship between VDR single nucleotide polymorphisms (SNPs) (ApaI, BsmI, FokI and TaqI) and the serum VDR and 25(OH)D levels in three groups of patients: (1) arthroscopy patients after THA without loosening of the prosthesis (CA-Control Arthroplasty), (2) patients after THA with loosened hip prostheses (L-Loosening) and (3) the control group (C-Control). Our results suggest that the genotypes tt of TaqI, BB of BsmI, and FF of FokI may influence the VDR effect in patients with loosened protheses. Our results showed that the ACAC haplotype (AtBF) was over two times more frequent in the L group than in CA + C: OR =2.35 [95% CI 1.44-3.83; p = 0.001]. There was no significant correlation between the VDR and serum 25(OH)D levels, but there were differences between studied groups.

Exploring the Role of Vitamin D, Vitamin D-Dependent Proteins, and Vitamin D Receptor Gene Variation in Lung Cancer Risk.

Lung cancer has an unfavorable prognosis with a rate of low overall survival, caused by the difficulty of diagnosis in the early stages and resistance to therapy. In recent years, there have been new therapies that use specific molecular targets and are effective in increasing the survival chances of advanced cancer. Therefore, it is necessary to find more specific biomarkers that can identify early changes in carcinogenesis and allow the earliest possible treatment. Vitamin D (VD) plays an important role in immunity and carcinogenesis. Furthermore, the vitamin D receptor (VDR) regulates the expression of various genes involved in the physiological functions of the human organism. The genes encoding the VDR are extremely polymorphic and vary greatly between human populations. To date, there are significant associations between VDR polymorphism and several types of cancer, but the data on the involvement of VDR polymorphism in lung cancer are still conflicting. Therefore, in this review, our aim was to investigate the relationship between VDR single-nucleotide polymorphisms in humans and the degree of risk for developing lung cancer. The studies showcased different gene polymorphisms to be associated with an increased risk of lung cancer: TaqI, ApaI, BsmI, FokI, and Cdx2. In addition, there is a strong positive correlation between VD deficiency and lung cancer development. Still, due to a lack of awareness, the assessment of VD status and VDR polymorphism is rarely considered for the prediction of lung cancer evolution and their clinical applicability, despite the fact that studies have shown the highest risk for lung cancer given by TaqI gene polymorphisms and that VDR polymorphisms are associated with more aggressive cancer evolution.

Study of Association of Vitamin D Receptor Gene Polymorphisms with Diabetic Nephropathy

Abstract Background: Type 2 diabetes leads to many microvascular complications, including diabetic nephropathy, also referred to as diabetic kidney disease. Vitamin D deficiency may play a role in the development of type 2 diabetes and nephropathy. The functions of vitamin D are mediated through vitamin D receptor (VDR). Three single nucleotide polymorphisms (SNPs) in VDR gene, namely, TaqI (rs731236), ApaI (rs7975232), and BsmI (rs1544410), have been widely studied in association with diabetes and nephropathy. The objective of this study was to investigate the association of these VDR gene SNPs with nephropathy in the South Indian population. Additionally, the effect of VDR gene variants on vitamin D levels was also investigated. Subjects and Methods: Two hundred forty-eight individuals with type 2 diabetes without nephropathy (T2DM) and 399 individuals with type 2 diabetes with nephropathy (T2DN) were genotyped for this study. Genotyping of TaqI was performed using the polymerase chain reaction-restriction fragment length polymorphism method. BsmI and ApaI were genotyped using MassArray. Anthropometric and biochemical data were collected for all participants. Vitamin D levels were measured in a subset of 47 T2DM and 74 T2DN individuals. Statistical analysis was performed using Statistical Package for the Social Sciences version 21.0 (IBM Corporation, Armonk, NY). Results: The genotype and minor allele frequencies of TaqI, BsmI, and ApaI were not significantly different between T2DM and T2DN groups. However, vitamin D levels were significantly reduced in T2DN (15.5 ± 1.16 ng/ml) compared to T2DM (20.5 ± 2.11 ng/ml, P = 0.027). No significant differences were found in the vitamin D levels when the T2DM and T2DN groups were stratified based on TaqI, BsmI, and ApaI genotypes. Conclusion: This study did not find a significant association of VDR SNPs (TaqI, BsmI, and ApaI) with T2DN. However, the study suggested a protective role of vitamin D levels in T2DN.

The Association of Vitamin D Receptor Polymorphisms with COVID-19 Severity.

Association studies of vitamin D receptor (VDR) polymorphisms with COVID-19 severity have produced inconsistent results in different populations. Herein we examined VDR gene polymorphisms in a Caucasian Greek cohort of COVID-19 patients. This was a case-control study in a tertiary university hospital in Greece including 137 COVID-19 patients with varying disease severities and 72 healthy individuals. In total 209 individuals were genotyped for the FokI (rs10735810), ApaI (rs7975232), TaqI (rs731236) and BsmI (rs1544410) single-nucleotide polymorphisms (SNP) of the VDR gene by polymerase chain reaction and restriction fragment length polymorphism analysis (PCR-RFLPs). Statistical analyses were performed to determine the association between genotype and disease severity, adjusting for various confounding factors. Genotype distribution of the studied VDR SNPs in the control group was in Hardy-Weinberg equilibrium. The TaqI variant was differentially distributed between controls and COVID-19 patients according to the additive model (p = 0.009), and the CC genotype was significantly associated with an increased risk for severe COVID-19 according to the recessive model [OR: 2.52, 95%CI:1.2-5.29, p = 0.01]. Multivariate analysis demonstrated a robust association of COVID-19 severity and TaqI polymorphism in the recessive model even after adjusting for multiple confounders, including age, sex and CRP levels [Adj.OR:3.23, 95%CI:1.17-8.86, p = 0.023]. The distribution of FokI, ApaI and BsmI genotypes was similar between COVID-19 patients and controls. The CC genotype of TaqI polymorphism is significantly associated with an increased risk for severe COVID-19 independently of age, sex or degree of inflammation.

Clinical and genetic determinants of vitamin D receptor expression in cutaneous melanoma patients.

Decrease of vitamin D receptor (VDR) expression is observed in melanocytic naevi and melanoma compared to normal skin. Little is known about factors influencing VDR expression in cutaneous melanoma (CM). We investigated the correlation of VDR expression in CM with 25-hydroxy vitamin D (25OHD) levels, demographic/clinical parameters, genetic variants of VDR and pathology of the primary tumor. Demographic/clinical parameters were recorded in 407 prospectively recruited CM patients of a multi-center controlled study (ViDMe trial). We determined VDR expression both in the nucleus and in the cytoplasm by semi-quantitative assessment in CM tissue using histochemistry in 279 patients, expressed in percentages and histoscore (H-score). Genomic DNA from 332 patients was extracted to genotype thirteen VDR single nucleotide polymorphisms (SNPs) using TaqMan. VDR expression in CM tissue from 279 patients was correlated with clinical/demographic parameters and 25OHD levels (univariable and multivariable analysis), VDR SNPs (univariable analysis) and pathology parameters of primary CM tissue (univariable analysis). Cytoplasmic VDR expression was increased in patients who stated to have a high sun exposure during their life compared to patients with low sun exposure (p H-score,univariable : 0.001, p H-score,multivariable : 0.004). The A allele of the genetic VDR polymorphism Fok1 was associated with a higher expression of the VDR in the cytoplasm (p cytoplasmic, univariable : 0.001 and p H-score, univariable : 0.02). In the primary tumor, presence of mitosis (p nucleus,%, univariable : 0.002) and perineural invasion (p nucleus,%,univariable : 0.03) were significantly associated with low nuclear VDR expression. ClinicalTrials.gov Identifier: NCT01748448.

Association of defects of enamel with polymorphisms in the vitamin D receptor and parathyroid hormone genes.

This cross-sectional study aimed to investigate the association between developmental defects of enamel (DDE) and single nucleotide polymorphisms (SNPs) in the genes encoding the vitamin D receptor (VDR) and parathyroid hormone (PTH). Orthodontic patients receiving treatment at a dental school were selected through convenience sampling. Intra-oral photographs were used to assess DDE, which were classified according to the criteria proposed by Ghanim et al. (2015) by a single calibrated examiner (Kappa>0.80). Enamel hypoplasia, molar-incisor hypomineralization (MIH), hypomimineralized second primary molar (HSPM), and non-MIH/HSPM demarcated opacities were considered for the analysis. Genomic DNA was extracted from buccal cells. The SNPs in VDR (rs7975232) and PHT (rs694, rs6256, and rs307247) were genotyped using real-time polymerase chain reactions (PCR). Statistical analyses were performed using the PLINK software (version 1.03, designed by Shaun Purcell, EUA). Chi-square or Fisher's exact tests were performed at a significance level of 5%. Ninety-one (n=91) patients (49 females and 42 males) (mean age of 14.1±5.8 years) were included. The frequency of DDE was 38.5% (35 patients). Genotype distributions were in Hardy-Weinberg equilibrium. No significant statistical association was found between DDE and the SNPs evaluated. A borderline association (p=0.09) was observed between DDE and the CC haplotype for SNP rs7975232 in VDR. In conclusion, the selected SNPs in VDR and PTH genes were not associated with DDE in the studied samples.

Altered Vitamin D Receptor Expression in Apa-I (rs7975232) Allelic Variants-A Probable Risk Factor for Susceptibility to Hepatitis B Virus Infection and Disease Progression.

Vitamin D exerts its antiviral effect through vitamin D receptor (VDR)/retinoid X receptor-mediated host immunomodulation. Besides the downregulation of VDR expression, its polymorphism was also observed among hepatitis B virus (HBV)-positive patients. To understand the possible link between VDR polymorphism and its altered expression during HBV infection and disease progression, VDR Apa-I [rs7975232 (C>A)] single nucleotide polymorphism (SNP) was analyzed in a case-control manner. VDR Apa-I (rs7975232, C>A) polymorphism was studied using 340 HBV patients and 102 healthy controls. Genotype analysis and gene expression study was performed using restriction fragment length polymorphism and quantitative polymerase chain reaction, respectively. Statistical analysis was performed using SPSS (IBM) considering p-value <0.05 as significant for comparing the differences between the groups. Significant mean difference in VDR expression was observed between HBV-positive patients (1.6 ± 0.94) and controls (0.69 ± 0.73). Furthermore, the mean fold change of Healthy control with CC genotype (1.92 ± 0.99) was found to be marginally significant compared with mutant genotype (CA/AA) (1.08 ± 0.43/0.59 ± 0.56, p = 0.045). In HBV+ patients, the mean fold change in the CC genotype was 0.88 ± 0.38, which exhibits a significant mean difference upon comparison with other genotypes (0.52 ± 0.49, 0.113 ± 0.34; p = 0.018, p = 0.048). However, the fold change value does not differ between CA and AA genotypes. Further comparative analysis of VDR expression between the control and case also exhibits significant differences (p = 0.001) among allelic variants. Observed genotype distribution frequency exhibits a significant association with disease type. The mutant genotype was found to be significantly associated with HBV infection and disease progression, (odds ratio = 0.730, 95% confidence interval = 0.462-1.152, p = 0.06). VDR SNP rs7975232 (C>A) may affect VDR expression by controlling several other variables and suggest that deviation from wild-type genotype (CC) is associated with downregulation of expression, which in turn involved in host immunomodulation in favor of HBV infection and disease progression.

The Influence of Single Nucleotide Polymorphisms on Vitamin D Receptor Protein Levels and Function in Chronic Liver Disease.

Single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene have been associated with chronic liver disease. We investigated the role of VDR SNPs on VDR protein levels and function in patients with chronic liver disease. VDR expression levels were determined in peripheral T lymphocytes (CD3+VDR+), monocytes (CD14+VDR+), and plasma from patients (n = 66) and healthy controls (n = 38). Genotyping of SNPs and the determination of expression of VDR/vitamin D-related genes were performed by using qPCR. The effect of FokI SNP on vitamin D-binding to VDR was investigated by molecular dynamics simulations. CD14+VDR+ cells were correlated with the MELD score. The ApaI SNP was associated with decreased CD3+VDR+ levels in cirrhotic patients and with higher liver stiffness in HCV patients. The BsmI and TaqI SNPs were associated with increased VDR plasma concentrations in cirrhotic patients and decreased CD14+VDR+ levels in HCV patients. The FokI SNP was associated with increased CD3+VDR+ levels in cirrhotic patients and controls. VDR polymorphisms were significantly related to the expression of genes critical for normal hepatocyte function and immune homeostasis. VDR expression levels were related to the clinical severity of liver disease. VDR SNPs may be related to the progression of chronic liver disease by affecting VDR expression levels.

Association of Vitamin D Receptor Gene Polymorphisms with Cardiometabolic Phenotypes in Hispanics: A Life Course Approach.

The vitamin D receptor (VDR) is vital for maintaining calcium and phosphate balance and regulating bone metabolism. Recent research has suggested that VDR also plays an essential role in metabolic diseases. Previous studies on non-Hispanic whites have shown that VDR single nucleotide polymorphisms (SNP) are associated with cardiometabolic phenotypes. However, the association between VDR SNPs and cardiometabolic traits in Hispanics remains unclear. This study investigated the association between VDR SNPs and cardiometabolic phenotypic data in self-reported Hispanics (n = 1610) from the Arizona Insulin Resistance registry and Sangre Por Salud Biobank. The study population was predominantly female (66.4%) with a mean age of 40 ± 14 years (n = 121 <18 years) and an average body mass index (BMI) of 29.8 ± 6.3 kg/m2. We performed a genotyping association analysis of VDR SNPs (Taq1-rs731236, Fok1-rs2228570 and Apa1-rs7975232) with cardiometabolic traits using linear regression models. The results showed that Taq1 and Apa1 were strongly associated with systolic blood pressure (SBP) in children (<18 years), while Fok1 was associated with measures of adiposity, including fat mass, waist circumference, and BMI. In age-stratified adult (≥18 years) models, Taq1 was strongly associated with hemoglobin A1c, while Apa1 was associated with BMI and fasting glucose. Fok1 had no significant associations in the adult models. In conclusion, the VDR SNPs were associated with several cardiometabolic phenotypes in this Hispanic sample, but the type and strength of the associations varied by age group.

Allelic Discrimination of Vitamin D Receptor Polymorphisms and Risk of Type 2 Diabetes Mellitus: A Case-Controlled Study.

(1) Background: Type 2 diabetes mellitus (T2DM) is one of the rapidly growing healthcare problems, and several vitamin D receptor (VDR) polymorphisms seem to modulate the risk of T2DM. Our research was designed to investigate the allelic discrimination of VDR polymorphisms and T2DM occurrence risk. (2) Methods: This case-control research included 156 patients with T2DM and 145 healthy control subjects. Most of the study population were males 56.6% vs. 62.8% in the case and control groups, respectively. Genotyping for VDR single nucleotide polymorphisms (SNPs), rs228570 (Fok1), rs7975232 (Apa1), and rs1544410 (Bsm1) was compared between both groups. (3) Results: There was a negative link between vitamin D levels and insulin sensitivity. A significant difference was noted in the allelic discrimination of VDR polymorphism rs228570 and rs1544410 between the study groups (p < 0.001). No difference was observed in the allelic discrimination of VDR polymorphism rs7975232 between the groups (p = 0.063). Moreover, T2DM patients had significantly higher levels of fasting blood sugar (FBS), glycated hemoglobin HbA1c, 2-h post-prandial blood sugar (PP), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic-pyruvic transaminase (SGPT), total cholesterol, and triglycerides (p < 0.001), while High-Density Lipoprotein (HDL) Cholesterol (HDL-C) was significantly decreased (p = 0.006). (4) Conclusions: VDR polymorphisms had a positive association with T2DM risk among the Egyptian population. Further large-scale research using deep sequencing of samples is strongly urged to investigate different vitamin D gene variants and interactions, as well as the influence of vitamin D on T2DM.

Association of vitamin D receptor polymorphisms with cardiometabolic conditions in Pakistani population.

Apart from bone related effects, vitamin D has roles in immune modulation, hypertension, diabetes and cardiovascular diseases. Metabolic functions of vitamin D are mediated after binding with vitamin D receptor (VDR). VDR polymorphisms affect its physiological functions. Several VDR single nucleotide polymorphisms (SNPs) were reported previously. However, VDR polymorphisms causing influence on cardiovascular and metabolic disorders have not been investigated in the Pakistani population so far. Therefore, the present study was conducted to evaluate the role of VDR polymorphisms (rs2228570 and rs7975232) in the pathobiology of cardiometabolic disorders. In total, 400 cardiometabolic patients and 226 healthy control human adults were enrolled from Faisalabad, Pakistan. Biochemical parameters (serum glucose, liver function test, renal function test and lipid profile) were analyzed by standard kit methods. Genetic analysis was done by ARMS-PCR assay. Data was analyzed in SPSS v20. Regression analysis revealed that GG and AG genotypes of rs2228570 A>G polymorphism significantly increased the risk of hypertension in cardiovascular patients by 5.29 and 5.94 times respectively (GG: OR=5.29, 95% CI=1.63-17.2, p=0.005; AG: OR=5.94, 95% CI=1.70-20.7, p=0.005). However, rs7975232 C>A polymorphism was not correlated with cardiometabolic conditions. In conclusion, GG and AG genotypes of VDR SNP rs2228570 significantly contribute to hypertension in cardiovascular disease patients.

Association of vitamin D levels and polymorphisms in vitamin D receptor with type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is a leading cause of death. The prevalence of T2DM in countries of the Middle East and North Africa (MENA) region, including Jordan, is among the highest worldwide. The reason(s) behind the epidemic nature of T2DM in Jordan are unknown but warrant further exploration. Studies have indicated that T2DM could be influenced by diet and/or genetic background. Evidence suggests that numerous patients with T2DM are deficient in vitamin D. The activity of vitamin D on its target tissues may be influenced by single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene. It was therefore hypothesized that SNPs in VDR could modify the risk of T2DM. To test this hypothesis, 125 patients with T2DM were recruited along with 125 controls. The study subjects were genotyped for variations in rs2228570, rs1544410, rs7975232, and rs731236 SNPs in the VDR. The levels of 25-hydroxyvitamin D [25(OH)D] were measured from the serum. The analysis revealed that reduced 25(OH)D and age were associated with the risk of T2DM (P<0.05). Moreover, under a dominant inheritance model, the GG genotype of rs2228570 was revealed to increase the risk of T2DM in univariate and multivariate analysis (P<0.05). Additionally, a chromosomal block containing the GAAG haplotype of VDR SNPs increased the risk of T2DM (OR=1.909; CI: 1.260-2.891; P=0.0021). Collectively, the present study revealed that low levels of serum 25(OH)D and rs2228570 of the VDR gene are associated with the risk of T2DM.

Significant association between TaqI and FokI VDR gene polymorphisms and chronic spontaneous urticaria in a Colombian Caribbean population.

Chronic spontaneous urticaria (CSU) is an inflammatory skin disease related to poor quality of life. Previous studies have found that vitamin D deficiency and vitamin D receptor (VDR) TaqI, BsmI, FokI, and ApaI gene single-nucleotide polymorphisms (SNPs) influence immune response and susceptibility to skin disorders. To explore the role of VDR SNPs, and the association of vitamin D serum levels in a sample of Colombian Caribbean CSU patients. Methods: It is a case-control study. A group of CSU patients (n = 100) was compared with healthy individuals as a control group (n = 100). VDR polymorphisms were genotyped by quantitative polymerase chain reaction and Taqman® probes. Allelic, genotypic, and haplotype associations were estimated. Serum vitamin D levels were measured using enzyme-linked-immunosorbent serologic assay. Compared to the control group, the presence of G allele in TaqI and A allele in FokI SNPs of VDR gene was found to be a risk factor for CSU (odds ratio (OR) estimated using logistic regression adjusted by gender: 2.08 and 1.61, respectively, all P values < 0.05). The individuals who carry GCCA haplotype showed decrease in vitamin D levels (11.34 ng/mL; P = 0.002) with the G allele of TaqI and A allele of FokI gene SNPs. We reported for the first time the association of TaqI [rs731236] and FokI [rs2228570] VDR gene SNPs showing as a risk factor for CSU in a sample of multiethnic patients from the Colombian Caribbean population.

Association of Genetic Polymorphism in Vitamin D Receptor and Paraoxonase I Genes with Type II Diabetes Mellitus Patients in Rural South Western Maharashtra

Background: Type II diabetes mellitus (T2DM) is increasing at an alarming rate in urban as well as rural parts of India. Change in life-style, dietary habits, aging, environmental factors contribute to developing this disorder, T2DM is a polygenic disorder which involves large number of genes interacting with each other and the environment to manifest itself phenotypically. Aims and Objectives: In the present study, we investigated the association of Vitamin D receptor (VDR) and Paraoxonase I (PON I) gene polymorphisms with T2DM patients among rural population in South western Maharashtra. Materials and Methods: The study groups included healthy non-diabetic control group (n = 120), non-obese diabetic group (n = 120), obese diabetic group (n = 120) from the same geographical region. The single nucleotide polymorphisms (SNPs) amongst these groups were studied using Polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) for VDR and PON I genes. Results and Conclusion: Amongst the studied genes VDR SNP rs1544410 [OR 0.24 (0.1-0.63); P 0.005] and Paraoxonase I SNP rs854560 (OR 0.47 (0.26-0.84); P 0.015) had a protective effect against T2DM for non-obese individuals. Whereas only VDR SNP rs1544410 [OR 0.025 (0.003-0.91); P 0.001] had a protective effect in case of obese individuals. The findings suggest greater gene-gene interaction and gene-environment interactions influence the phenotypic outcomes of genetic polymorphisms.

Vitamin D Metabolites Are Associated with Physical Performance in Young Healthy Adults.

This study aimed to determine vitamin D metabolites and vitamin D receptor (VDR) single-nucleotide polymorphism (SNP) relationships with physical performance. In 1205 men and 322 women (94.8% White Caucasian, 22.0 ± 2.8 yr) commencing military training, we measured serum vitamin D metabolites (25-hydroxyvitamin D (25(OH)D) and 24,25-dihydroxyvitamin D (24,25(OH) 2 D) by high-performance liquid chromatography tandem mass spectrophotometry and 1,25-dihydroxyvitamin D (1,25(OH) 2 D) by immunoassay), VDR SNPs (rs2228570, rs4516035, and rs7139166 by polymerase chain reaction genotyping), and endurance performance by 2.4-km run, muscle strength by maximal dynamic lift, and muscle power by maximal vertical jump. Serum 25(OH)D was negatively associated with 2.4-km run time and positively associated with muscle power ( β = -12.0 and 90.1), 1,25(OH) 2 D was positively associated with run time and negatively associated with strength and muscle power ( β = 5.6, -1.06, and -38.4), and 24,25(OH) 2 D was negatively associated with run time ( β = -8.9; P < 0.01), after controlling for age, sex, smoking, alcohol, physical activity, time outdoors, season, and body mass index. Vitamin D metabolites (25(OH)D, 1,25(OH) 2 D, and 24,25(OH) 2 D) together explained variances of 5.0% in run time, 0.7% in strength, and 0.9% in muscle power (Δ F P < 0.001). All performance measures were superior with low 1,25(OH) 2 D:24,25(OH) 2 D ratio ( P < 0.05). VDR SNPs were not associated with physical performance (Δ FP ≥ 0.306). Vitamin D metabolites accounted for a small portion of variance in physical performance. Associations between vitamin D metabolites and run time were the most consistent. VDR SNPs explained no variance in performance. Greater conversion of 25(OH)D to 24,25(OH) 2 D, relative to 1,25(OH) 2 D (i.e., low 1,25(OH) 2 D:24,25(OH) 2 D ratio), was favorable for performance, indicating 24,25(OH) 2 D may have a role in optimizing physical performance.

Crosstalk Between Gut Microflora and Vitamin D Receptor SNPs Are Associated with the Risk of Amnestic Mild Cognitive Impairment in a Chinese Elderly Population.

The interactions between environmental factors and genetic variants have been implicated in the pathogenesis of Alzheimer's disease (AD). The altered gut microbiota (GM) and vitamin D deficiency are closely associated with the higher risk of AD. This study was performed to evaluate whether the crosstalk between GM and single nucleotide polymorphisms (SNPs) of vitamin D receptor (VDR) or vitamin D binding protein (VDBP) have a link with the risk of amnestic mild cognitive impairment (aMCI) in the Chinese elderly population. A total of 171 aMCI patients and 261 cognitive normal controls (NC) were enrolled in this study. Six tag SNPs of VDR and VDBP were genotyped by PCR-RFLP. The serum levels of vitamin D, Aβ1-42, and p-tau (181P) were determined by using of ELISA kits. The alterations in the GM were analyzed by full-length 16S ribosomal RNA (rRNA) gene sequencing. The frequencies of AG genotype and A allele of VDR rs1544410 in aMCI group were significantly higher than that in NC group (genotype: p = 0.002, allele: p = 0.003). Patients with aMCI showed an abnormal GM composition compared with NC group. Interestingly, significant differences in GM composition were found between aMCI and NC group among individuals with AG genotype, as well as between individuals with AG and GG genotype of VDR rs1544410 among patients with aMCI. These results implicated that the crosstalk between gut microflora and vitamin D receptor variants are associated with the risk of aMCI in Chinese elderly population.

Genetic Variability of the Vitamin D Receptor Affects Susceptibility to Parkinson's Disease and Dopaminergic Treatment Adverse Events.

Vitamin D is a lipid-soluble molecule and an important transcriptional regulator in many tissues and organs, including the brain. Its role has been demonstrated also in Parkinson’s disease (PD) pathogenesis. Vitamin D receptor (VDR) is responsible for the initiation of vitamin D signaling cascade. The aim of this study was to assess the associations of VDR genetic variability with PD risk and different PD-related phenotypes. We genotyped 231 well characterized PD patients and 161 healthy blood donors for six VDR single nucleotide polymorphisms, namely rs739837, rs4516035, rs11568820, rs731236, rs2228570, and rs1544410. We observed that VDR rs2228570 is associated with PD risk (p < 0.001). Additionally, we observed associations of specific VDR genotypes with adverse events of dopaminergic treatment. VDR rs1544410 (GG vs. GA + AA: p = 0.005; GG vs. GA: p = 0.009) was associated with the occurrence of visual hallucinations and VDR rs739837 (TT vs. GG: p = 0.036), rs731236 (TT vs. TC + CC: p = 0.011; TT vs. TC: p = 0.028; TT vs. CC: p = 0.035), and rs1544410 (GG vs. GA: p = 0.014) with the occurrence of orthostatic hypotension. We believe that the reported study may support personalized approach to PD treatment, especially in terms of monitoring vitamin D level and vitamin D supplementation in patients with high risk VDR genotypes.