Promoter and 3'-untranslated-region haplotypes in the vitamin d receptor gene predispose to osteoporotic fracture: the rotterdam study

The Effect of Genetic Variations in the Vitamin D Receptor Gene on the Course of Depressive Symptoms

BACKGROUND

Evidence on the association between single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) and depressive symptoms is inconclusive.

OBJECTIVES

The primary aim of the study was to investigate the association between SNPs in the VDR gene and depressive symptoms.

METHODS

In a sample of older adults from the Longitudinal Ageing Study Amsterdam (n = 922), depressive symptoms were assessed using the Centre for Epidemiological Studies Depression scale (CES-D scale) at baseline and after 3, 6, and 10 y of follow-up. Blood samples for SNP and serum 25-hydroxyvitamin D3 (25(OH)D3) determination were obtained at baseline. The association between 13 SNPs in the VDR gene and the course of depressive symptoms were evaluated using linear mixed models. The interaction between SNPs and serum 25(OH)D3 in relation to depressive symptoms was evaluated using multiple linear regression.

RESULTS

No SNPs were associated with the course of depressive symptoms. Significant interactions between serum 25(OH)D3 and SNPs in the VDR gene were found. Stratified analysis revealed that within the GG genotype strata, 10 nmol/L higher serum 25(OH)D3 was associated with 0.27 (95% CI: -0.50, -0.04) and 0.23 (95% CI: -0.48, 0.02) lower scores on the CES-D scale for Cdx-2 and 1b-G-886A, respectively. This association was not found in persons having the GA or AA genotype.

CONCLUSIONS

No SNPs are associated with the course of depressive symptoms. Stratified analysis shows that the effect of serum 25(OH)D3 concentrations on depressive symptoms is different among genotypes of Cdx-2 and 1b-G-886A. Future research should elucidate on the function of Cdx-2 and 1b-G-886A to describe their effect.

Vitamin D Receptor Polymorphisms in a Spanish Cohort of Parkinson's Disease Patients

Background: Vitamin D receptor (VDR) is a nuclear hormone receptor widely expressed in the substantia nigra. Its association with an increased risk of Parkinson's disease (PD) is based on vitamin D deficiency and/or different polymorphisms in its gene receptor. This fact has been demonstrated by several case-control studies. Materials and Methods: Consequently, we investigated the association between VDR ApaI, BsmI, FokI, and TaqI gene polymorphisms and PD in a Spanish cohort that included 54 cases and 17 healthy controls. The detection of single nucleotide polymorphisms (SNPs) was performed using a polymerase chain reaction-restriction fragment length polymorphism. Results: Our data indicate that the SNPs were not associated with the age of onset of PD, nor with the occurrence of motor symptoms. However, only BsmI polymorphism was significantly associated with PD in this Spanish cohort. In fact, BsmI genotype was five times higher among PD patients than among controls, and the A allele was considered as a genetic risk for PD. Additionally, the combination of FokI and BsmI polymorphisms was significantly associated with PD and could represent a risk factor. Conclusion: We conclude that ApaI, TaqI, and FokI polymorphisms were not associated with PD, but BsmI could be a risk factor for PD in this randomized population.

Vitamin D and Its Receptors in Cervical Cancer

Several studies have investigated the relationship between vitamin D (VD) and its receptors (VDR) and the risk of cervical cancer. However, the underlying mechanisms that underpin these associations remain incompletely comprehended. In this review, we analyzed the impacts of VD and VDR on cervical cancer and related mechanisms, and discussed the effects of VD, calcium, and other vitamins on cervical cancer. Our literature research found that VD, VDR and their related signaling pathways played indispensable roles in the occurrence and progression of cervical cancer. Epidemiological studies have established associations between VD, VDR, and cervical cancer susceptibility. Current studies have shown that the inhibitory effect of VD and VDR on cervical cancer may be attributed to a variety of molecules and pathways, such as the EAG potassium channel, HCCR-1, estrogen and its receptor, p53, pRb, TNF-α, the PI3K/Akt pathway, and the Wnt/β-catenin pathway. This review also briefly discussed the association between VDR gene polymorphisms and cervical cancer, albeit a comprehensive elucidation of this relationship remains an ongoing research endeavor. Additionally, the potential ramifications of VD, calcium, and other vitamins on cervical cancer has been elucidated, yet further exploration into the precise mechanistic underpinnings of these potential effects is warranted. Therefore, we suggest that further studies should focus on explorations into the intricate interplay among diverse molecular pathways and entities, elucidation of the mechanistic underpinnings of VDR polymorphic loci changes in the context of HPV infection and VD, inquiries into the mechanisms of VD in conjunction with calcium and other vitamins, as well as investigations of the efficacy of VD supplementation or VDR agonists as part of cervical cancer treatment strategies in the clinical trials.

Association between vitamin D receptor gene FokI polymorphism and mortality in patients with sepsis

BACKGROUND

Sepsis is life-threatening organ dysfunction as a result of the host's dysregulated immune response to infection. The vitamin D receptor (VDR) gene FokI polymorphism influences immune cell behavior. In the present study, we aimed to investigate the association between VDR FokI polymorphism and mortality in sepsis and non-sepsis patients in the intensive care unit (ICU).

METHODS AND RESULTS

This is a prospective observational study involving 96 sepsis and 96 non-sepsis patients admitted to the Ege University ICU. VDR FokI polymorphisms were investigated, as well as the relationship between the identified polymorphisms and mortality.  In-hospital mortality was 27.1% in the sepsis group and 8.33% in the non-sepsis group (p = 0.001). The frequencies of VDR FokI TT, TC, and CC genotypes were 8 (8.33%), 48 (50.0%), and 40 (41.7%) in the sepsis group, and 11 (11.5%), 42 (43.8%), and 43 (44.8%) in the non-sepsis group, respectively (p = 0.612). In the sepsis group, the frequencies of Fokl TT, TC, and CC genotypes did not differ significantly between survivors and non-survivors. However, homozygous C allele carriers had lower overall mortality (p = 0.047).

CONCLUSION

The VDR FokI polymorphism, particularly the CC genotype, appears to be associated with lower mortality in ICU patients.

The vitamin D receptor agonist EB1089 can exert its antiviral activity independently of the vitamin D receptor

Vitamin D has been shown to have antiviral activity in a number of different systems. However, few studies have investigated whether the antiviral activity is exerted through the vitamin D receptor (VDR). In this study, we investigated whether the antiviral activity of a vitamin D receptor agonist (EB1089) towards dengue virus (DENV) was modulated by VDR. To undertake this, VDR was successively overexpressed, knocked down and retargeted through mutation of the nuclear localization signal. In no case was an effect seen on the level of the antiviral activity induced by EB1089, strongly indicating that the antiviral activity of EB1089 is not exerted through VDR. To further explore the antiviral activity of EB1089 in a more biologically relevant system, human neural progenitor cells were differentiated from induced pluripotent stem cells, and infected with Zika virus (ZIKV). EB1089 exerted a significant antiviral effect, reducing virus titers by some 2Log10. In support of the results seen with DENV, no expression of VDR at the protein level was observed. Collectively, these results show that the vitamin D receptor agonist EB1089 exerts its antiviral activity independently of VDR.

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.

Gene Polymorphisms and Biological Effects of Vitamin D Receptor on Nonalcoholic Fatty Liver Disease Development and Progression

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, with increasing prevalence worldwide. The genetic and molecular background of NAFLD pathogenesis is not yet clear. The vitamin D/vitamin D receptor (VDR) axis is significantly associated with the development and progression of NAFLD. Gene polymorphisms may influence the regulation of the VDR gene, although their biological significance remains to be elucidated. VDR gene polymorphisms are associated with the presence and severity of NAFLD, as they may influence the regulation of adipose tissue activity, fibrosis, and hepatocellular carcinoma (HCC) development. Vitamin D binds to the hepatic VDR to exert its biological functions, either by activating VDR transcriptional activity to regulate gene expression associated with inflammation and fibrosis or by inducing intracellular signal transduction through VDR-mediated activation of Ca²⁺ channels. VDR activity has protective and detrimental effects on hepatic steatosis, a characteristic feature of NAFLD. Vitamin D-VDR signaling may control the progression of NAFLD by regulating immune responses, lipotoxicity, and fibrogenesis. Elucidation of the genetic and molecular background of VDR in the pathophysiology of NAFLD will provide new therapeutic targets for this disease through the development of VDR agonists, which already showed promising results in vivo.

Investigating Vitamin D Receptor Genetic Markers in a Cluster Headache Meta-Analysis

Patients diagnosed with the primary headache disorder known as cluster headache (CH) commonly report that their headache attacks occur in patterns of both circadian and seasonal rhythmicity. Vitamin D is essential for a variety of bodily functions and vitamin D levels are largely regulated by daylight exposure in connection with seasonal variation. For this Sweden-based study, the association between CH and three single-nucleotide polymorphisms in the vitamin D receptor gene, rs2228570, rs1544410, and rs731236, were investigated, as well as CH bouts and trigger factors in relation to seasonal and weather changes. Over 600 study participants with CH and 600 controls were genotyped for rs2228570, and genotyping results for rs1544410 and rs731236 were obtained from a previous genome-wide association study. The genotyping results were combined in a meta-analysis, with data from a Greek study. No significant association was found between rs2228570 and CH or the CH subtype in Sweden, nor did the meta-analysis show significant results for any of the three markers. The most common period of the year to experience CH bouts in Sweden was autumn, and conditions linked to weather or weather changes were also identified as potential triggers for CH bouts for a quarter of the responders who reported bout triggers. Though we cannot rule out vitamin D involvement in CH, this study does not indicate any connection between CH and the three vitamin D receptor gene markers.

Effects of prenatal exposure to the 1944-45 Dutch famine and glucocorticoid receptor polymorphisms on later life PTSD susceptibility

Background: Exposure to adversity in utero is thought to increase susceptibility to develop posttraumatic stress disorder (PTSD) following later life trauma, due to neurobiological programming effects during critical developmental periods. It remains unknown whether effects of prenatal adversity on PTSD susceptibility are modulated by genetic variations in neurobiological pathways implicated in PTSD susceptibility.Objective: We investigated whether genetic variation in the glucocorticoid receptor (GR) modulated effects of prenatal famine exposure on late adulthood PTSD symptom severity after trauma exposure in childhood and mid-to-late adulthood.Method: We included N = 439 term-born singleton adults (mean age: 72 years, 54.2% women) from the Dutch Famine Birth Cohort, born around the time of the Dutch Famine of 1944/1945, divided into exposure and control groups based on timing of the famine during gestation. Participants filled out self-report questionnaires on childhood (Childhood Trauma Questionnaire) and mid-to-late adulthood (Life Events Checklist for DSM-5) trauma, and current PTSD symptom severity (PTSD Checklist for DSM-5). GR haplotypes were determined from four functional GR single nucleotide polymorphisms (ER22/23EK, N363S, BclI and exon 9β) in previously collected DNA. Linear regression analyses were performed to investigate associations of GR haplotype and prenatal famine exposure in conjunction with later life trauma on PTSD symptom severity.Results: We observed a significant three-way interaction between the GR Bcll haplotype, famine exposure during early gestation, and adulthood trauma exposure on PTSD symptom severity in late adulthood. Only participants exposed to famine during early gestation without the GR Bcll haplotype showed a significantly stronger positive association between adulthood trauma and PTSD symptom severity than non-exposed participants, indicating increased PTSD susceptibility.Conclusions: Our results illustrate the importance of integrated approaches considering genetics and environmental contexts throughout various life periods, including the rarely investigated prenatal environment, to elucidate how PTSD susceptibility evolves throughout life.HIGHLIGHTS Adversity during pregnancy is thought to increase offspring's PTSD risk following later life trauma, but exact neurobiological mechanisms underlying this process remain unknown.We found that effects of prenatal famine exposure on PTSD symptom severity were influenced by genetic variation in the glucocorticoid receptor, which signals effects of the stress hormone cortisol.Integrated approaches considering genetics and environmental contexts throughout both early and later life are important to understand how PTSD risk evolves throughout life.

[Vitamin D and polymorphisms of VDR and GC genes in the severity and mortality from COVID-19. A systematic review]

Introduction

Previous studies have pointed to a possible relationship between vitamin D deficiency and the severity of the disease promoted by SARS-CoV-2, reducing respiratory and cardiovascular complications caused by a hyperreaction of the immune system known as "cytokine storm". This vitamin exerts multiple functions that depend on the presence and levels of different proteins, such as the vitamin D receptor (VDR) and the vitamin D binding protein (DBP), and the existence of single nucleotide polymorphisms (SNPs) of the genes that encode these proteins. The objective of this review is to assess whether some VDR and GC SNPs are risk factors for the most severe forms of COVID-19 disease and whether they condition the response to vitamin D supplementation. A search was performed in PubMed, Google Scholar and Scielo, finding that genotypes in patients affected by COVID-19, were rarely performed, although some studies find a relationship between different alleles and the severity of the disease. The ApaI polymorphism of the VDR gene stands out, as the minor allele "a" increases the risk of mortality from COVID-19 (OR = 11.828, CI: 2,493-56,104, p = 0.002). Results divergency in the efficacy of vitamin D supplementation suggest the need for a larger number of studies. In conclusion, the study of VDR and GC polymorphisms seems essential to effectively treat vitamin D deficiency and particularly to protect against COVID-19. Well-designed studies are needed to elucidate whether plasma vitamin D levels play a role of casuality or causality.

The association between vitamin D receptor polymorphism and phases of chronic hepatitis B infection in HBV carriers in Thailand

Vitamin D receptor (VDR) polymorphism partly regulates the immune system and is associated with hepatic flare in chronic Hepatitis B virus infection (HBV). Our study identified the association between two distinct phases, VDR polymorphisms and HBV inactive carrier (IC) and chronic hepatitis (CH). Chronic HBV patients were enrolled from February to August 2020. An HBV viral load (VL) < 2,000 IU/ml twice for 6 months apart, with no prior history of HBV treatment, defined the IC phase. Six common polymorphisms in the VDR gene, including CdX-2, GATA, FokI, Bsml, ApaI, and TaqI, were studied using real-time PCR. The different outcomes in allele, genotype, and haplotype frequencies in between groups and linkage disequilibrium (LD) mapping were analyzed. Among 324 enrolled patients, there were 163 patients in IC and 161 patients in CH phases. The mean vitamin D levels were not statistically different between groups. The proportion of allele frequencies of CdX-2 in IC and CH was 53.7% and 62.7% for G allele, and 46.3% and 37.3% for A allele (p 0.019). The proportion of GG genotype of CdX-2 was less frequently found in patients with IC compared to that in patients with CH (27% vs 41%, p 0.028). By multivariate analysis, CdX-2 G/A genotypes were independently associated with IC, with adjusted odd ratio (OR) 1.83 (1.10-3.04), p 0.019. The LD mapping of single nucleotide polymorphisms (SNP) revealed high LD scores in Bsml/ApaI/TaqI (BAT) haplotype in both groups while, CdX-2/GATA and GATA/FokI demonstrated high LD score only in CH group. CdX-2 G/A genotypes were independently associated with IC status in Thai patients with chronic HBV infection. The difference in LD of the CdX-2/GATA and GATA/FokI haplotypes in between groups may represent a non-random selection resulting in the variation of immune control.

The relationship between VDR polymorphisms and keratinocyte carcinomas: a systematic review and meta-analysis

Aim: To perform a meta-analysis to assess the association between common VDR polymorphisms (Fok1, Taq1, Apa1, Bsm1) and keratinocyte carcinomas (KCs) susceptibility. Methods & materials: databases were searched up to November 2021. Odds ratios (OR) with 95% CIs were evaluated in the association. Results: This meta-analysis included seven articles. KC (and its subtypes) risks are found to be associated with Fok1 (BCC: ff vs FF+Ff: OR = 2.13, 95% CI = 1.14-3.97; SCC: ff vs FF+Ff: OR = 1.54, 95% CI = 1.09-2.18) and Taq1 (BCC: Tt vs TT: OR = 1.99, 95% CI = 1.35-2.93; tt vs TT: OR = 2.09, 95% CI = 1.27-3.43; Tt +tt vs TT: OR = 2.02, 95% CI = 1.41-2.90) polymorphisms. Conclusion: This study suggests that the Fok1 f allele and the Taq1 t allele are associated with increased susceptibility to KC and its subtypes.

Gene polymorphisms in asthma: a narrative review

Background and Objective

Asthma is a heterogeneous disease caused by interactions between genetic and environmental factors. Genome-wide association studies (GWAS) have revealed that genetic variation plays a crucial role in the occurrence and development of asthma. The objective is to systematically review the existing literature on the association between gene polymorphisms and asthma to better understand the relationship between genetic factors and the occurrence and development of asthma.

Methods

We used keywords "asthma" and "gene polymorphism" with their combinations to search for relevant literature published from 2000 to 2021 in the PubMed database and the foreign medical literature retrieval service (FMRS). All articles included in the review are English. Then, we summarized the information pertaining to the genetic factors related to asthma susceptibility.

Key Content and Findings

This study summarized the information on 10 gene variants related to the risk of asthma published over the past 20 years, which will assist in further understanding the role of genetic variants in the risk of asthma.

Conclusion

Dozens of candidate genes have been identified that were associated with asthma risk. Asthmatics existed specific gene variation performed different response to therapy. Personalized therapy based on genotypic profiling would be an important direction in the future. However, it remains a great challenge for us to explore the relationship between gene polymorphisms and pathophysiological mechanism of asthma.

Vitamin D Receptor Genetic Variations May Associate with the Risk of Developing Late Fracture-Related Infection in the Chinese Han Population

Variations in the vitamin D receptor (VDR) gene are related to several inflammatory disorders. However, the potential links between such alternations and the risk of developing late fracture-related infection (FRI) remain unclear. This study investigated associations between genetic variations in the VDR and susceptibility to late FRI in the Chinese Han population. Between January 2016 and December 2019, 336 patients with late FRI and 368 healthy controls were genotyped six VDR genetic variations, including ApaI (rs7975232), BsmI (rs1544410), FokI (rs2228570), TaqI (rs731236), GATA (rs4516035), and Cdx-2 (rs11568820). Significant associations were observed between rs7975232 and FRI susceptibility in the recessive (P = 0.019, OR = 0.530, 95% CI 0.310–0.906) model. Patients with AA genotype had a relatively higher level of serological vitamin D (20.6 vs. 20.3 vs. 17.9 ng/ml) (P = 0.021) than those of AC and CC genotypes. Although no statistical differences were observed, potential correlations may exist between rs1544410 (dominant model: P = 0.079, OR = 0.634), rs2228570 (dominant model: P = 0.055, OR = 0.699), and rs4516035 (dominant model: P = 0.065, OR = 1.768) and the risk of FRI development. In the Chinese cohort, ApaI was associated with a decreased risk of developing FRI, and patients with the AA genotype had a higher vitamin D level. Further studies are required to assess the role of genetic variations in BsmI, FokI, and GATA in the pathogenesis of late FRI.

Vitamin D receptor gene polymorphisms in chronic kidney disease Egyptian children: effect on biochemical markers of bone mineral disorders

INTRODUCTION

The aim of this study was to assess the association between four vitamin D receptor (VDR) single nucleotide polymorphisms BsmI (rs1544410), ApaI (rs7975232), FokI (rs2228570) and TaqI (rs731236) and the susceptibility to chronic kidney disease (CKD) in Egyptian children and to evaluate their association with mineral status in these patients.

MATERIAL AND METHODS

The current study included 305 patients with CKD and 100 apparently healthy children. We measured the serum vitamin D (VD), para-thyroid hormone (PTH) level and fibroblast growth factor 23 (FGF-23) levels by ELISA method. The genotyping of the four VDR gene variants was carried out by PCR-RFLP technique.

RESULTS

The TaqI AG &amp; the BsmI TT genotypes were associated with a significantly higher risk of CKD. The expression of 25-OH D serum level was decreased in patients with TaqI GG &amp; AG genotypes groups and in patients with BsmI TT genotype group The expression of PTH serum level was increased in patients with BsmI CT genotype group. The expression of FGF-23 serum level was increased in patients with Taq1 AG genotype group. We found 3 specific haplotypes; AGCA, AGCC and GGCA for healthy controls.

CONCLUSIONS

Our study showed an association between VDR TaqI, BsmI polymorphisms and the susceptibility to CKD. The existence of VDR vari-ants affected the protein expression of VD, FGF-23 and PTH. The AGCA, AGCC and GGCA haplotypes were considered as protec-tive factors against the development of renal nephropathy in our population.

Polymorphisms in vitamin D receptor, toll-like receptor 2 and Toll-Like receptor 4 genes links with Dengue susceptibility

Host genetic factors are known to determine disease susceptibility in dengue virus infection. Therefore, in this study association of gene polymorphisms of Vitamin D Receptor [rs731236 (Taq) and rs7975232 (Apa1)], Toll-like receptor 2 [rs5743708 (Arg735Gln) and rs5743704 (Pro631His)] and Toll-like receptor 4 [rs4986790A/G(Asp299Gly13843) and rs4986791 C/T(Thr399Ile)] were studied in cases with dengue as compared to controls. Total 98 cases of confirmed dengue virus infection and 98 age, sex and geographically matched healthy controls were enrolled and their genetic polymorphisms for the above mentioned regions were studied by Sanger sequencing. Mutant genotypes CC of VDR rs731236 (Taq1) [(OR 3.808, p value =0.02, CI 1.160-12.498)], GG of VDR rs7975232 (Apa1) [(OR 3.485, p value =0.02, CI 1.162-10.45)] and heterozygous genotypes of TLR4 rs4986790 A/G Asp299Gly [OR 2.40, p value= 0.02, CI 1.12-5.14], TLR4 rs4986791 C/T Thr399Ile [OR 2.09, p value=0.02, CI 1.12-5.14] were found to be significantly more in cases with dengue virus infection as compared to the controls. Also, at these positions mutant alleles were observed in significantly higher number of cases than controls. The values for C allele at VDR rs731236 (Taq1) were OR 1.86, p value 0.009, CI 1.162-3.001; for allele G at rs7975232( Apa1) were OR 2.71, p value 0.006, CI 1.196-2.98 for allele G at TLR4s rs4986790 A/G Asp299Gly were OR 2.35, p value 0.009, CI 1.23-4.50 and for allele T at rs4986791 C/T Thr399Ile were OR 2.36, p value=0.006, CI 1.28-4.38. VDR and TLR4 but not TLR2 gene polymorphisms were found to be associated with dengue susceptibility in Indian population.

Vitamin D Receptor Gene Variants Susceptible to Osteoporosis in Arab Post-Menopausal Women

Post-menopausal osteoporosis (PMO) is a multifactorial bone disorder in elderly women. Various vitamin D receptor (VDR) gene variants have been studied and associated with osteoporosis in other populations, but not in a homogenous Arab ethnic group. Herein, the current study explores the association between VDR polymorphisms and susceptibility to osteoporosis in Saudi postmenopausal women. In total, 600 Saudi postmenopausal women (N = 300 osteoporosis; N = 300 control) were genotyped for VDR gene variants (rs7975232, rs1544410, rs731236) using TaqMan^® SNP genotyping assays. Bone mineral density (BMD) for the lumbar spine and femur was assessed using dual-energy X-ray absorptiometry (DEXA). The heterozygous frequency distributions AC of rs7975232, CT of rs1544410, and AG of rs731236 were significantly higher in the osteoporosis group than controls (p < 0.05). Heterozygous AC of rs7975232 (1.6; 95% CI 1.1–2.3; p < 0.023), CT of rs1544410 (1.6; 95% CI 1.1–2.4; p < 0.022), and AG of rs731236 (1.6; 95% CI 1.1–2.4; p < 0.024) were significantly associated with increased risk of osteoporosis, independent of age and BMI. In conclusion, VDR gene variants rs7975232, rs1544410, rs731236 had a significant effect on BMD and were associated with osteoporosis risk in Saudi postmenopausal women.

Growth, Dietary Intake, and Vitamin D Receptor (VDR) Promoter Genotype in Indonesian School-Age Children

Nutrition has been known as a predominant factor associated with stunting. However, some studies have discovered a genetic contribution in calcium absorption that will affect growth, known as the VDR gene. The aim of this study was to assess the association between VDR gene polymorphism and dietary intake towards height-for-age z-score (HAZ) of elementary school children in Malang District, East Java. This study analyzed the baseline of a randomized trial in East Java, Indonesia. School children aged 8–10 years old (n = 142) were included in this study. Energy, protein, calcium, and vitamin D intakes were obtained using 4-day 24-h dietary recalls. Two SNPs located in the promoter region of VDR gene were selected (rs11568820 and rs4516035) and analyzed using Real-Time PCR. The result showed a significant correlation between energy and protein intake with HAZ of the children (p = 0.030 and p = 0.016, respectively). The association between VDR gene and HAZ was not found (p > 0.05). Adjusted by other factors, protein intake was significantly correlated with HAZ (β = 0.034, 95% CI 0.015–0.052, p < 0.001, adj. R² = 0.089). The children in our study had a favorable VDR gene genotype, however the effect of VDR gene promoter activity might not be revealed due to very low vitamin D and calcium intake to stimulate intestinal calcium absorption which in turn affects HAZ.

Vitamin D receptor gene polymorphism TaqI (rs731236) and its association with the susceptibility to coronary artery disease among Pakistani population

BACKGROUND

Coronary artery disease (CAD) is a leading cause of mortality in Pakistan and also worldwide. Vitamin D receptor (VDR) regulates the transcription of many genes and has a significant impact on inflammation and the morphology of cardiac cells. Genetic variation in the VDR gene such as the TaqI polymorphism (rs731236) may have an impact that causes adverse effects. Accordingly, it is important to determine possible association of the TaqI polymorphism (rs731236) with CAD.

METHODS

The study included blood samples from 1016 subjects: 516 from CAD patients and 500 from age- and gender-matched controls. Genomic DNA was extracted by standard salting out method. Targeted variation was amplified by an allele-specific polymerase chain reaction (PCR). PCR products were examined and genotyped on agarose gel electrophoresis represented by an amplified product size of 148 bp followed by Sanger sequencing to validate variations.

RESULTS

Serum vitamin levels, as observed using enzyme-linked immunosorbent assay, were found to be insufficient in both CAD patients (20.52 ± 0.06 ng/ml) and controls (21.6981 ± 0.05 ng/ml). The TaqI polymorphism (rs731236) T>C was found to be significantly associated with CAD (p < 0.0001). The odds ratio showed that the risk increases by 1.8-fold with variant C allele. Dominant, co-dominant and over dominant genetic model analyses suggested that the TC genotype might be a risk factor involved in the possible association with susceptibility to CAD.

CONCLUSIONS

The TaqI polymorphism (rs731236) in the coding region may affect the function of the receptor by altering the binding site, which might participate in an inflammatory response and increase the risk for developing susceptibility to CAD.

Potential Role of Perilacunar Remodeling in the Progression of Osteoporosis and Implications on Age-Related Decline in Fracture Resistance of Bone

PURPOSE OF REVIEW

We took an interdisciplinary view to examine the potential contribution of perilacunar/canalicular remodeling to declines in bone fracture resistance related to age or progression of osteoporosis.

RECENT FINDINGS

Perilacunar remodeling is most prominent as a result of lactation; recent advances further elucidate the molecular players involved and their effect on bone material properties. Of these, vitamin D and calcitonin could be active during aging or osteoporosis. Menopause-related hormonal changes or osteoporosis therapies affect bone material properties and mechanical behavior. However, investigations of lacunar size or osteocyte TRAP activity with age or osteoporosis do not provide clear evidence for or against perilacunar remodeling. While the occurrence and potential role of perilacunar remodeling in aging and osteoporosis progression are largely under-investigated, widespread changes in bone matrix composition in OVX models and following osteoporosis therapies imply osteocytic maintenance of bone matrix. Perilacunar remodeling-induced changes in bone porosity, bone matrix composition, and bone adaptation could have significant implications for bone fracture resistance.

Association of Vitamin D Receptor Polymorphisms with Amyloid-β Transporters Expression and Risk of Mild Cognitive Impairment in a Chilean Cohort

Background: Amyloid-β peptide (Aβ) deposition in Alzheimer’s disease (AD) is due to an imbalance in its production/clearance rate. Aβ is transported across the blood-brain barrier by LRP1 and P-gp as efflux transporters and RAGE as influx transporter. Vitamin D deficit and polymorphisms of the vitamin D receptor (VDR) gene are associated with high prevalence of mild cognitive impairment (MCI) and AD. Further, vitamin D promotes the expression of LRP1 and P-gp in AD-animal model brains. Objective: To associate VDR polymorphisms Apa I (rs7975232), Taq I (rs731236), and Fok I (rs2228570) with the risk of developing MCI in a Chilean population, and to evaluate the relationship of these polymorphisms to the expression of VDR and Aβ-transporters in peripheral blood mononuclear cells (PBMCs). Methods: VDR polymorphisms Apa I, Taq I, and Fok I were determined in 128 healthy controls (HC) and 66 MCI patients. mRNA levels of VDR and Aβ-transporters were evaluated in subgroups by qPCR. Results: Alleles A of Apa I and C of Taq I were associated with a lower risk of MCI. HC with the Apa I AA genotype had higher mRNA levels of P-gp and LRP1, while the expression of VDR and RAGE were higher in MCI patients and HC. For Fok I, the TC genotype was associated with lower expression levels of Aβ-transporters in both groups. Conclusion: We propose that the response to vitamin D treatment will depend on VDR polymorphisms, being more efficient in carriers of protective alleles of Apa I polymorphism.

Vitamin D Receptor (VDR) Allelic Variants Correlating with Response to Vitamin D3 Supplementation in Breast Cancer Survivors

We investigated how vitamin D receptor (VDR) allelic variants affect breast cancer survivors' responses to vitamin D3 supplementation to increase circulating 25-hydroxy vitamin D (25(OH)D) levels. Two hundred and fourteen patients who were diagnosed with breast cancer at least 6 mo, prior to the study and had completed all treatment regimens were assigned to consume 4000 IU of vitamin D3 daily for 12 weeks. Linear and multinomial logistic regression analyses were used to analyze the association of VDR single nucleotide polymorphism (SNPs) with changes in circulating 25(OH)D. The TaqI and BsmI VDR sequence variants modified the effect of vitamin D3 treatment on the plasma 25(OH)D changes (P value = 0.008 for TaqI and P value = 0.0005 for BsmI). Patients with the bb [Q4 vs. Q1 odds ratio(OR) 8.04, 95% confidence interval (CI) 1.55-41.57] and tt [Q4 vs. Q1 OR 4.64 95%CI 1.02-21.02] genotype of BsmI and TaqI had larger increases in plasma 25(OH)D levels compared to those with BB and TT genotype respectively after adjustment for potential confounders. Haplotype analyses suggested the existence of specific combination of alleles that might be associated with circulating 25(OH)D changes. VDR allelic variants modulate vitamin D3 supplementation to increase plasma 25(OH) levels in breast cancer survivors.

Review of Current Real-World Experience with Teriparatide as Treatment of Osteoporosis in Different Patient Groups

Teriparatide has proven effective in reducing both vertebral and non-vertebral fractures in clinical trials of post-menopausal and glucocorticoid-induced osteoporosis. Widespread adoption of Teriparatide over the last two decades means that there is now substantial experience of its use in routine clinical practice, which is summarized in this paper. Extensive real-world experience of Teriparatide in post-menopausal osteoporosis confirms the fracture and bone density benefits seen in clinical trials, with similar outcomes identified also in male and glucocorticoid-induced osteoporosis. Conversely, very limited experience has been reported in pre-menopausal osteoporosis or in the use of Teriparatide in combination with other therapies. Surveillance studies have identified no safety signals relating to the possible association of Teriparatide with osteosarcoma. We also review the evidence for predicting response to Teriparatide in order to inform the debate on where best to use Teriparatide in an increasingly crowded therapeutic landscape.

Vitamin D Status, Bone Mineral Density, and VDR Gene Polymorphism in a Cohort of Belarusian Postmenopausal Women

Vitamin D plays an important role in bone metabolism and is important for the prevention of multifactorial pathologies, including osteoporosis (OP). The biological action of vitamin is realized through its receptor, which is coded by the VDR gene. VDR gene polymorphism can influence individual predisposition to OP and response to vitamin D supplementation. The aim of this work was to reveal the effects of VDR gene ApaI rs7975232, BsmI rs1544410, TaqI rs731236, FokI rs2228570, and Cdx2 rs11568820 variants on bone mineral density (BMD), 25-hydroxyvitamin D level, and OP risk in Belarusian women. Methods. The case group included 355 women with postmenopausal OP, and the control group comprised 247 women who met the inclusion criteria. TaqMan genotyping assay was used to determine VDR gene variants. Results. Rs7975232 A/A, rs1544410 T/T, and rs731236 G/G single variants and their A-T-G haplotype showed a significant association with increased OP risk (for A-T-G, OR = 1.8, p = 0.0001) and decreased BMD (A-T-G, −0.09 g/cm², p = 0.0001). The rs11568820 A-allele showed a protective effect on BMD (+0.22 g/cm², p = 0.027). A significant dose effect with 25(OH)D was found for rs1544410, rs731236, and rs11568820 genotypes. Rs731236 A/A was associated with the 25(OH)D deficiency state. Conclusion. Our novel data on the relationship between VDR gene variants and BMD, 25(OH)D level, and OP risk highlights the importance of genetic markers for personalized medicine strategy.

Association between Vitamin D Receptor Polymorphisms (BsmI and FokI) and Glycemic Control among Patients with Type 2 Diabetes

(1) Background: Several studies have suggested that the vitamin D receptor (VDR) gene plays a role in type 2 diabetes mellitus (T2DM) susceptibility. Nonetheless, the association between T2DM and VDR polymorphisms remains inconclusive. We determined the genotype of VDR rs1544410 (BsmI) and rs2228570 (FokI) polymorphisms among Malaysian patients with T2DM and their association with glycemic control factors (vitamin D levels, calcium, magnesium, and phosphate). (2) Methods: A total of 189 participants comprising 126 patients with T2DM (63 with good glycemic control and 63 with poor glycemic control) and 63 healthy controls were enrolled in this case-control study. All biochemical assays were measured using spectrophotometric analysis. VDR gene FokI and BsmI polymorphisms were analyzed using polymerase chain reaction and endonuclease digestion. (3) Results: Our findings revealed no significant differences in VDR FokI and BsmI genotypes between participants with T2DM and healthy controls. Moreover, no significant association was observed between both single nucleotide polymorphisms and glycemic control factors. Participants with poor glycemic control had significantly lower serum magnesium levels and significantly higher HOMA-IR compared to the other groups. (4) Conclusions: The present study revealed that VDR gene BsmI and FokI polymorphisms were not significantly associated with T2DM.

Association between Gene Polymorphisms of Vitamin D Receptor and Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

(1) Background: Studies on the association between Vitamin D receptor gene polymorphism and gestational diabetes mellitus have been inconsistent. The aim of this study was to summarize available evidence on the association between polymorphisms of Vitamin D receptor genes and susceptibility to gestational diabetes mellitus. (2) Methods: We searched databases of PubMed, Web of Science, Embase, China national knowledge infrastructure (CNKI), China science and technology journal database (VIP), and Wanfang Data for relevant articles. A systematic review and a meta-analysis were done to compare the distribution of Vitamin D receptor gene polymorphisms in gestational diabetes mellitus patients with those in controls using allelic, codominant, dominant, and recessive models. (3) Results: A total of eight eligible articles were included in the systematic review and of them, six articles were included in the meta-analysis. The vitamin D receptor gene rs7975232 polymorphism was associated with gestational diabetes mellitus under the allelic model (odds ratio = 1.28, 95% confidence interval 1.06–1.56), codominant model (CC vs. AA odds ratio = 1.97, 95% confidence interval 1.28–3.05), and recessive model (odds ratio = 1.83, 95% confidence interval 1.27–2.64) in the case of low heterogeneity. High heterogeneity existed in studies on the association of vitamin D receptor genes rs1544410, rs2228570, and rs731236 with gestational diabetes mellitus, and the most common sources of heterogeneity were the year of publication and matching. (4) Conclusion: Polymorphism of the vitamin D receptor gene rs7975232 may be associated with risk of developing gestational diabetes mellitus. Future studies should be designed to include standardized data collection and matching for important confounding factors such as body mass index, age, and race.

Adaptation and co-adaptation of skin pigmentation and vitamin D genes in native Americans

We carried out an exhaustive review regarding human skin color variation and how much it may be related to vitamin D metabolism and other photosensitive molecules. We discuss evolutionary contexts that modulate this variability and hypotheses postulated to explain them; for example, a small amount of melanin in the skin facilitates vitamin D production, making it advantageous to have fair skin in an environment with little radiation incidence. In contrast, more melanin protects folate from degradation in an environment with a high incidence of radiation. Some Native American populations have a skin color at odds with what would be expected for the amount of radiation in the environment in which they live, a finding challenging the so-called "vitamin D-folate hypothesis." Since food is also a source of vitamin D, dietary habits should also be considered. Here we argue that a gene network approach provides tools to explain this phenomenon since it indicates potential alleles co-evolving in a compensatory way. We identified alleles of the vitamin D metabolism and pigmentation pathways segregated together, but in different proportions, in agriculturalists and hunter-gatherers. Finally, we highlight how an evolutionary approach can be useful to understand current topics of medical interest.

Is it reasonable to ignore vitamin D status for musculoskeletal health?

Severe vitamin D deficiency—25-hydroxyvitamin D (25OHD) concentrations below around 25–30 nmol/L—may lead to growth plate disorganization and mineralization abnormalities in children (rickets) and mineralization defects throughout the skeleton (osteomalacia) and proximal muscle weakness. Both problems are reversed with vitamin D treatment. Apart from this musculoskeletal dysfunction at very low vitamin D levels, there is apparent inconsistency in the available data about whether concentrations of 25OHD below around 50 nmol/L cause muscle function impairment and increase the risk of fracture. This narrative review provides evidence to support the contention that improving vitamin D status, up to around 50 nmol/L, plays a small causal role in optimizing bone and muscle function as well as reducing overall mortality.

Vitamin D receptor gene polymorphisms are associated with psoriasis susceptibility and the clinical response to calcipotriol in psoriatic patients

Psoriasis is a common genetic disease characterized by hyperproliferation and disordered maturation of keratinocytes. To date, many association studies between psoriasis and VDR gene have been conducted, but the results are controversial. Furthermore, vitamin D₃ analogue has anti-psoriatic activity; however, the clinical response is variable. This study was conducted to explore whether VDR gene polymorphisms are associated with psoriasis susceptibility and clinical response to calcipotriol in psoriatic patients. A total of 110 patients and 183 controls were genotyped for VDR gene polymorphisms rs2228570, rs731236, rs1544410 and rs7975232 by LDR method. SNP-based and haplotype-based association analyses were subsequently performed. Patients with PASI < 3 were treated with calcipotriol ointment monotherapy. After 6 weeks of therapy, the correlations between efficacy and the genotypes of each polymorphism were evaluated. The results showed that for rs7975232, allele A was significantly over-represented in psoriasis patients relative to controls (39.09% vs. 27.05%, OR (95% CI) = 1.731 (1.213-2.471)), and compared with the reference CC genotype, the following ORs were observed: AA genotype OR = 2.404 (95% CI: 1.085-5.328; P = .034) and GA genotype OR = 2.143 (95% CI: 1.283-3.579; P = .005). Haplotype analyses showed that the rs2228570/rs731236/rs1544410/rs7975232 CTGA was significantly over-represented in psoriasis patients compared with controls (OR (95% CI)=1.907 (1.132-3.214); P = .020). Among the patients with PASI < 3, the response rates to calcipotriol were significantly higher in patients with rs7975232 CC genotypes than in those with other genotypes (x²  = 9.172, P = .010). These data suggest that VDR polymorphisms are associated with psoriasis susceptibility and clinical response to calcipotriol in psoriatic patients.

The Association Between the Genetic VDR SNP c.907+75C>T and Prostate Cancer Risk Is Modified by Tanning Potential

BACKGROUND

Prostate cancer (PCa) is a multifactorial disease involving complex interactions between genetic and physiological/environmental factors. Vitamin D receptor (VDR) plays a role in numerous cellular pathways and it has been suggested that VDR genetic variants influence individual susceptibility to PCa.

MATERIALS AND METHODS

Logistic regression analysis was used to assess the association of six VDR single nucleotide polymorphisms (SNPs) and factors such as tanning potential and UV sunlight exposure with PCa risk.

RESULTS

Marginal significant interactions were found, with a 2-fold increase risk of PCa between SNP 1 (c.278-69G>A) and sunlight UV exposure [odds ratio (OR)=2.02, 95% confidence intervaI (CI)=1.036-4.36; p=0.05]; and a 4-fold increase risk of PCa between SNP 4 (c.907+75C>T) and tanning potential (OR=4.40, 95% CI=0.89-29.12; p=0.0591). In contrast, SNP 5 (rs731236, TaqI) and tanning potential interaction had a protective effect by reducing the risk of PCa by 55% (β=-0.804; OR=0.448, 95% CI=0.197-9.42; p=0.0427). SNPs 2 (rs61614328) and 6 (rs533037428) did not show any association with PCa even in the presence of UV sunlight exposure.

CONCLUSION

The protective effect of SNP 4 from PCa is lost and modified by tanning potential in African Americans. This finding needs to be verified by larger studies in different ethnic populations.

Associations between vitamin D receptor gene polymorphisms and spinal degenerative disease: evidence from a meta-analysis based on 35 case-control studies

OBJECTIVE

Dozens of reports on the associations of vitamin D receptor (VDR) gene polymorphisms and susceptibility to spinal degenerative disease (SDD) were conducted with inconsistent findings. This study aimed to elucidate the associations through a meta-analysis approach.

METHODS

Databases of PubMed, EMBASE, Web of Science, CNKI, and Wanfang were searched until July 10, 2020. Study quality was evaluated by using Newcastle-Ottawa Scale (NOS). Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated to evaluate the associations under allelic model (1 vs. 2), homozygous model (11 vs. 22), heterozygous model (12 vs. 22), dominant model (11 + 12 vs. 22), and recessive model (11 vs. 12 + 22).

RESULTS

A total of 5021 cases and 5746 controls from 35 studies were eligible to this meta-analysis. According to NOS, the included studies were in excellent quality. In the overall population, the pooled data indicated that ApaI was associated with a reduced SDD susceptibility (AA vs. Aa + aa, OR = 0.83, 95%CI 0.71 - 0.96, P = 0.010). But the association was not observed in FokI, TaqI, and BsmI polymorphisms. Subgroup analysis suggested that TaqI polymorphism was correlated to an elevated SDD risk in Asians (TT + Tt vs. tt, OR = 2.55, 95%CI 1.90 - 3.44, P < 0.001).

CONCLUSION

The present study indicates that ApaI polymorphism may contribute to a reduced risk to SDD in the overall population, and TaqI polymorphism confers an elevated susceptibility to SDD in Asians. While, BsmI and FokI polymorphisms appear to have no significant association with SDD.

Vitamin D Binding Protein (VDBP) and Its Gene Polymorphisms-The Risk of Malignant Tumors and Other Diseases

Vitamin D is an important component of the endocrine system that controls calcium homeostasis and bone mineralization. Because of the very short half-life of free serum vitamin D it is stabilized and transported to target tissues by being bound to the vitamin D binding protein (VDBP). The most common polymorphisms: rs4588 and rs7041 in the vitamin D binding protein gene may correlate with differences in vitamin D status in the serum. This review presents data that relate to the presence of genetic variants in the VDBP gene in correlation with certain diseases, mostly concerning cancers (breast, prostate, pancreatic, lung, colorectal, basal cell carcinoma cancer and cutaneous melanoma) or other related diseases (thyroid autoimmunity disorders, obesity, diabetes mellitus, bone metabolism, rheumatoid arthritis, ankylosing spondylitis, asthma, chronic obstructive pulmonary disease, tuberculosis and coronary artery diseases).

BsmI-ApaI-TaqI TAC (BAt) Haplotype of Vitamin D Receptor Gene Is Associated with Increased Risk of Major Depressive Disorder

Heritability of major depressive disorder (MDD) is between 36 and 44%, suggesting that up to nearly half of the phenotypic variability is attributable to genes. A number of genetic polymorphisms have been shown to predispose certain individuals to depression. Of particular interest are the polymorphisms of the vitamin D receptor (VDR) gene. Although the VDR gene has been well characterized and a vast number of polymorphisms have been identified, the association between BsmI (rs1544410), ApaI (rs7975232) and TaqI (rs731236) single-nucleotide polymorphisms (SNPs), together with their haplotypes, and MDD risk have yet to be established. We conducted a matched case-control study with a total of 600 participants comprising 300 major depressive disorder (MDD) cases and 300 controls matched by age, gender and ethnicity in a 1:1 ratio, in four public hospitals in Kuala Lumpur and Selangor. Three adjacent SNPs of the VDR gene-BsmI (rs1544410), ApaI (rs7975232) and TaqI (rs731236)-were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Odds ratios and 95% confidence intervals (CIs) were obtained from conditional logistic regression using Stata 16. Linkage disequilibrium and haplotype association with MDD were analyzed using the online SNPStats program. None of the genotypes of the three SNPs was significantly associated with risk of developing MDD after adjusting for confounding factors. However, the TAC (BAt) haplotype was associated with increased odds of MDD (adjusted OR = 2.17, 95% CI = 1.30-3.61, p = 0.003) using CCT (baT) as reference haplotype. The findings suggest that the BsmI-ApaI-TaqI TAC (BAt) haplotype of the VDR gene increases susceptibility to MDD.

Genetic risk factors for lumbar disc disease

AIM AND BACKGROUND

Lumbar disc degeneration (LDD) is thought to be multifactorial in origin. Very recently the focus has shifted to the involvement of a family of candidate genes in the pathogenesis of LDD. There is particular emphasis on the vitamin D receptor gene (VDR gene). The VDR polymorphisms FOK1, TAQ1, and APO1 have been variably associated with LDD.

OBJECTIVE

To evaluate the association between the FOK1/Taq1 genes and LDD.

MATERIALS AND METHODS

One hundred unrelated healthy (asymptomatic) individuals who presented for routine health checkup and 93 consecutive patients (43 males and 50 females) with no history of low back pain were enrolled in the study after informed consent was obtained. The MRI images of cases and controls were graded and peripheral blood samples were collected from all participants and sent for genetic analysis.

RESULTS

Individuals with the dominant genotype for Taq1 had a significantly higher association with LDD than those without it. There was no association between LDD and the Fok1 genotype.

CONCLUSION

Genetic predisposition is an important risk factor for LDD.

Association between Vitamin D Receptor Single-Nucleotide Polymorphisms and Colorectal Cancer in the Thai Population: A Case-Control Study

Vitamin D and its cognate intracellular nuclear receptor, namely, vitamin D receptor (VDR), are involved in the regulation of a variety of body metabolic processes, immune function, and oncogenesis. A large number of studies demonstrated the association of low vitamin D levels and variations in five common single nucleotide polymorphisms (SNPs), FokI, BsmI, Tru9I, ApaI, and TaqI, with the risk of several cancers, including colorectal cancers. However, these associations vary among different populations. This case-control study was aimed at analysing whether common single-nucleotide polymorphisms (SNPs) and haplotypes of the vitamin D receptor (VDR) gene contribute to colorectal carcinogenesis in the Thai population. We enrolled 364 Thai participants from King Chulalongkorn Memorial Hospital between 2014 and 2015. Half of the participants underwent colonoscopy and showed a normal colon without polyps (control group) and another half were newly diagnosed patients with colorectal cancer (CRC) by colonoscopy during the index period, were under treatment, or were followed up at the outpatient clinic (case group). Differences in allele and genotype frequencies of five common VDR SNPs, between the case and control groups, were the primary outcome measures. Differences in haplotype frequencies of the five SNPs between the case and control groups were the secondary outcome measures. Among the 364 participants, baseline characteristics were not significantly different between the case and control groups, except for the higher proportion of males in the CRC group. The mean vitamin D level was also not significantly different between the case and control groups (24.6 ± 9.1 vs. 25.3 ± 10.6 ng/mL, p = 0.52). None of the five VDR SNPs was associated with CRC development (p > 0.05). However, haplotype analysis of these polymorphisms demonstrated that the AGGT haplotype was associated with a decreased risk of CRC (odds ratio 0.24, 95% confidence interval 0.07-0.81, p = 0.01). The AGGT haplotype was associated with a lower risk of CRC in the Thai population. This genetic linkage might support the role of vitamin D in colorectal carcinogenesis. However, this finding requires further study within a larger population and a multivariate analysis of other established risk factors.

Interplay between vitamin D receptor FokI polymorphism and smoking influences Porphyromonas gingivalis proportions in subgingival plaque

AIM

This cross-sectional study investigated the effect of the vitamin D receptor (VDR) FokI polymorphism and its interactions with smoking/drinking on the proportions of periodontal pathogens and periodontitis severity.

MATERIALS AND METHODS

FokI genotyping and bacterial quantification were performed using real-time polymerase chain reaction. Periodontitis severity was determined using mean clinical attachment level (CAL). Regression analyses examined the associations between the FokI polymorphism (rs2228570) and bacterial proportions or periodontitis severity. Effect modification by smoking or drinking was assessed.

RESULTS

The study population comprised 1,460 individuals, aged 39-66 years. After multivariable adjustment, the FokI risk genotypes (CC + CT) were associated with elevated Porphyromonas gingivalis proportions (regression coefficient (β) =0.294 ± 0.139; p = .034) and increased mean CAL (β = 0.130 ± 0.048; p = .007). The effect of the FokI polymorphism on P. gingivalis proportions was greater in smokers (β = 0.897 ± 0.328; p = .006) compared to non-smokers (β = 0.164 ± 0.153; p = .282) and in drinkers (β = 0.668 ± 0.242; p = .006) compared to non-drinkers (β = 0.114 ± 0.169; p = .500). The genotype*smoking interaction for P. gingivalis proportions was significant (p = .043), whereas the genotype*drinking interaction was not (p = .061). Similar results were found for the effect of the genotype*smoking/drinking interaction on mean CAL.

CONCLUSIONS

These findings suggest that the interplay between the host genotype and smoking is important in determining the subgingival microbial composition and periodontitis severity.

Genetic and epigenetic regulation of natural resistance to HIV-1 infection: new approaches to unveil the HESN secret

Introduction: Since the identification of HIV, several studies reported the unusual case of small groups of subjects showing natural resistance to HIV infection. These subjects are referred to as HIV-1-exposed seronegative (HESN) individuals and include people located in different areas, with diverse ethnic backgrounds and routes of exposure. The mechanism/s responsible for protection from infection in HESN individuals are basically indefinite and most likely are multifactorial.Areas covered: Host factors, including genetic background as well as natural and acquired immunity, have all been associated with this phenomenon. Recently, epigenetic factors have been investigated as possible determinants of reduced susceptibility to HIV infection. With the advent of the OMICS era, the availability of techniques such as GWAS, RNAseq, and exome-sequencing in both bulk cell populations and single cells will likely lead to great strides in the understanding of the HESN mystery.Expert opinion: The employment of increasingly sophisticated techniques is allowing the gathering of enormous amounts of data. The integration of such information will provide important hints that could lead to the identification of viral and host correlates of protection against HIV infection, allowing the development of more effective preventative and therapeutic regimens.

Association between vitamin D receptor polymorphisms and susceptibility to Parkinson's disease: An updated meta-analysis

The relationships between vitamin D receptor (VDR) gene polymorphisms, particularly ApaI, BsmI, FokI, and TaqI, and Parkinson's disease (PD) has received increasing attention in the research community. However, as the results yielded by this increased research have hitherto conflicted, we performed an updated meta-analysis of reports on the relationships between VDR polymorphisms and PD published before October 2019 that we collected from the PUBMED, EMBASE, EBSCO, China National Knowledge Infrastructure (CNKI), and Wanfang databases. The ten articles that met our screening criteria included 2782 patients and 3194 healthy controls. All the data that we received were analyzed with Stata 12.0 statistical software. The odds ratio (OR) and 95 % confidence intervals (CIs) were used to determine the relationship between VDR gene diversity and PD. While we did not find a significant correlation between the ApaI, BsmI, and TaqI polymorphisms and the risk of PD in any of the considered genetic models, we found a clear association between the FokI polymorphism and susceptibility to PD (C vs. T: OR = 1.246, 95 % CI: 1.101-1.411, P = 0; CC vs. TT: OR = 1.630, 95 % CI: 1.243-2.139, P = 0; CT vs. TT: OR = 1.382, 95 % CI: 1.059-1.804, P = 0.017; CC + CT vs. TT: OR = 1.491, 95 % CI: 1.159-1.919,P = 0.002; CC vs. CT + TT: OR = 1.261, 95 % CI: 1.062-1.496, P = 0.008). Our subgroup analysis performed according to ethnicity revealed that FokI increased the risk of PD in Asian populations (C vs. T: OR = 1.261, 95 % CI: 1.080-1.472, P = 0.003; CC vs. TT: OR = 1.664, 95 % CI: 1.189-2.330, P = 0.003; CT vs.TT: OR = 1.387, 95 % CI: 1.000-1.925, P = 0.05; CC + CT vs. TT: OR = 1.497, 95 % CI: 1.098-2.042, P = 0.011; CC vs. CT + TT: OR = 1.285, 95 % CI: 1.036-1.593, P = 0.022). Overall, the gene polymorphism of FokI only increases the risk of PD among Asian populations. Given the limited sample size of this study, the findings should be carefully explained.

Genetic influence of vitamin D receptor gene polymorphisms on osteoporosis risk

OBJECTIVE

Osteoporosis is the most common type of bone disorder characterized by low bone mineral density (BMD). It is a multifactorial disease and caused by the interaction of environmental and genetic factors. It has been reported that mutations in the vitamin D receptor (VDR) gene highly affect the metabolism of minerals, which reduces bone density. Therefore, this study aimed to determine the association of VDR gene polymorphisms TaqI (rs731236) and ApaI (rs7975232) with osteoporosis risk in the Saudi population.

METHODS

This case-control study involved 73 individuals with osteoporosis and 73 healthy controls in Jeddah, KSA. DNA extracted from peripheral blood was used to determine the genotypes and allele frequencies of VDR variants by polymerase chain reaction-restriction fragment length polymorphisms. Osteoporosis was confirmed by measuring BMD using dual-energy X-ray absorptiometry. The results were interpreted using the Hardy-Weinberg equilibrium assumption with P < 0.05 considered as significant.

RESULTS

A significant increase in the genotype frequencies of the ApaI (Aa) and (aa) was observed among osteoporotic patients compared to controls (P = 0.002 and P < 0.0001, respectively). Only the homozygous (tt) genotype of TaqI was significantly higher in those with osteoporosis than in the controls (P = 0.001). The minor "a" allele of ApaI and the "t" allele of TaqI were significantly more common in the patients as compared to controls (P < 0.0001 and P = 0.01, respectively).

CONCLUSION

VDR polymorphisms ApaI and TaqI were found to be significantly determinant risk factors for osteoporosis progression in the Saudi population.

The Effect of Caffeine on Calcitriol-Inducible Vitamin D Receptor-Controlled Gene Expression in Intestinal and Osteoblastic Cells

Some epidemiological studies suggested caffeine consumption as the cause for bone mineral density loss. Certain genes involved in this process are regulated by vitamin D receptor (VDR). Therefore, we investigated if caffeine can affect inducible expression of VDR-regulated genes, some of them being involved in bone mineralization process. By employing reporter gene assay, polymerase chain reaction, and western blotting, we monitored the VDR activity and expression in cell cultures of intestinal (LS180), osteosarcoma (HOS), and normal human osteoblasts in vitro. While caffeine stimulated calcitriol-inducible VDR-dependent nanoluciferase activity in stable reporter cell line IZ-VDRE (derived from LS180), it rather modulated mRNA levels of target genes, like CYP24A1, BGLAP, SPP1, and TNSF11 in LS180 and HOS cells. However, caffeine significantly decreased calcitriol-inducible CYP24A1, TNSF11, and SPP1 transcripts in osteoblasts. This decrease had non-linear U-shaped profile. Our in vitro data demonstrate biphasic action of caffeine on the expression of certain calcitriol-inducible VDR-regulated genes in normal human osteoblasts.

Association of vitamin D receptor gene polymorphisms with disc degeneration

PURPOSE

Numerous candidate genes and single-nucleotide polymorphisms (SNPs) have been identified in the background of lumbar disc degeneration (LDD). However, in most of these underpowered studies, definitions of LDD are inconsistent; moreover, many of the findings have not been replicated and are contradictory. Our aim was to characterize LDD by well-defined phenotypes and possible endophenotypes and analyse the association between these and candidate vitamin D receptor (VDR) gene polymorphisms on a large (N = 1426) dataset.

METHODS

Seven candidate VDR SNPs were genotyped. Individual association, haplotype and gene-gene interaction analyses were performed. All degenerative endophenotypes were significantly associated with one or more candidate VDR gene variants.

RESULTS

Haplotype analyses confirmed the association between the 3'-end VDR variants (BsmI, ApaI, TaqI) and Modic changes as well as the relationship of 5'-end variants (Cdx2, A1012G) with endplate defects. We also found significant interactions between the 3'- and 5'-end regulatory regions and endplate defects. Based on our results, VDR and its gene variants are highly associated with specific degenerative LDD endophenotypes.

CONCLUSION

Understanding relationships between phenotype and gene variants is crucial for describing the pathways leading to the multifactorial, polygenic degeneration process and LDD-related conditions. These slides can be retrieved under Electronic Supplementary Material.

Association between polymorphisms in GGPS1 and RANKL genes and postmenopausal osteoporosis in Romanian women

Objectives: This study aimed to assess the relationship between bone mineral density, fragility fractures, fracture risk and polymorphisms of two osteoporosis-candidate genes (GGPS1 and RANKL) in Romanian women with postmenopausal osteoporosis. Methods: An analytical, prospective, transversal, observational, case-control study on 364 postmenopausal women, of which 228 were previously diagnosed with osteoporosis, was carried out between June 2016 and August 2017 in Cluj Napoca, Romania. Clinical data and blood samples were collected from all study participants. Polymorphisms in GGPS1 and RANKL genes were genotyped using TaqMan SNP Genotyping assays, run on a QuantStudio 3 real-time PCR machine. Results: The CT genotype in GGPS1 rs10925503 was associated with significant lower bone mineral density values at lumbar spine and femoral neck sites and a higher fracture risk compared to controls. No significant association was found between genotypes of RANKL rs2277439 with bone mineral density or fracture risk compared to the healthy controls. Conclusions: Our study showed a strong association between low bone mineral density and genotype CT of GGPS1 rs10925503 polymorphisms. No association was found for RANKL rs2277439 polymorphism.

Vitamin D Receptor Gene Polymorphisms and Autoimmune Thyroiditis: Are They Associated with Disease Occurrence and Its Features?

Purpose

Vitamin D, besides its role in calcium-phosphorus metabolism, turned out to play a significant immunomodulating function. Until now four single nucleotide polymorphisms of vitamin D receptor gene (VDR), rs2228570 (FokI), rs1544410 (BsmI), rs7975232 (ApaI), and rs731236 (TaqI), have been studied in autoimmune thyroid disorders, with conflicting results. Another functional polymorphism of the VDR gene, rs11568820 (Cdx2), has been shown to influence the immune system, although it has not been studied for its association with autoimmune thyroiditis to date. Therefore, the study aimed to evaluate the association of these five VDR gene polymorphisms with susceptibility to autoimmune thyroiditis among Caucasian Polish population. A relationship between the studied polymorphisms and selected clinical features of the disease was additionally assessed.

Methods

223 patients with autoimmune thyroiditis and 130 control subjects were enrolled in the study. VDR polymorphisms were studied by PCR-RFLP or TaqMan real-time PCR.

Results

Allele and genotype distributions of any of the studied polymorphisms did not differ significantly between patients and controls. Similarly, frequencies of haplotypes derived from rs1544410-rs7975232-rs731236 (BsmI-ApaI-TaqI) polymorphisms were not significantly different in the two studied groups. However, a weak association between rs1544410 (BsmI) or rs7975232 (ApaI) VDR polymorphisms and thyroid volume was found (p = 0.03 and p = 0.04, resp.).

Conclusions

Our results suggest that VDR gene is not a major susceptibility factor for autoimmune thyroiditis development, at least in Caucasian Polish population.

Vitamin D receptor gene polymorphisms affecting changes in visceral fat, waist circumference and lipid profile in breast cancer survivors supplemented with vitamin D3

OBJECTIVE

We investigated whether vitamin D receptor (VDR) polymorphisms are associated with circulating metabolic biomarkers and anthropometric measures changes in breast cancer survivors supplemented with vitamin D3.

METHODS

One hundred sixty-eight breast cancer survivors admitted to Shohaday-e-Tajrish hospital received 4000 IU of daily vitamin D3 supplements for 12 weeks. Anthropometric measurements as well dietary, physical activity and plasma metabolic biomarkers assessments were performed before and after intervention. VDR polymorphisms were considered as the main exposures. Multivariate multiple linear regression analyses were used to determine the association between the VDR single-nucleotide polymorphisms (SNPs) and changes in metabolic and anthropometric measures in response to vitamin D3 supplementation.

RESULTS

One hundred twenty-five (85%) women had insufficient and inadequate levels of plasma 25-hydroxy vitamin D (25(OH)D) at baseline. Compared to the AA genotype of the ApaI, the aa category showed greater increase in muscle mass [71.3(10.7131.9)] and higher decrease in LDL-C [- 17.9(- 33.6, - 2.3)] levels after adjustment for potential confounders. In addition, the heterozygous genotype (Bb) of the BsmI VDR was associated with higher increase in WC following vitamin D3 supplementation, compared to BB [2.7(0.1,5.3)]. Haplotype score analyses indicate a significant association between inferred haplotypes from BsmI, ApaI, TaqI and FokI, BsmI and Cdx2 VDR polymorphisms and on-study visceral fat changes.

CONCLUSIONS

Findings of this study showed that genetic variation in the VDR gene was associated with changes in cardio-metabolic parameters in breast cancer survivors, supplemented with vitamin D3, results could provide a novel insight into better understanding of which subset of individuals benefit most from normalization of vitamin D status.

TRIAL REGISTRATION

This trial has been registered on the Iranian Registry of Clinical Trials (IRCT) under the identification code: IRCT2017091736244N1, registration date: 2017-11-10, http://www.irct.ir/trial/27153 and was approved by the ethics committees of the National Nutrition and Food Technology Research Institute (NNFTRI), Shahid Beheshti University of Medical Sciences (SBMU).

Vitamin D receptor gene polymorphisms are associated with triceps skin fold thickness and body fat percentage but not with body mass index or waist circumference in Han Chinese

Background

Evidence shows that low serum vitamin D concentrations account for an increased risk of obesity by inducing vitamin D receptor (VDR) hypofunction. Although the correlation between single nucleotide polymorphisms (SNPs) of VDR gene and obesity-related anthropometric measures (such as body mass index [BMI] and waist circumference[WC]) has already been tested, there are only few studies on the association between direct measures of body fat percentage (BFP) and triceps skinfold thickness and the SNPs of VDR. The aim of the present study was to evaluate the effect of VDR gene polymorphism on multiple obesity indexes in Han Chinese, including BMI, WC, BFP and triceps skinfold thickness.

Methods

In this cross-sectional study, five hundred and seventeen healthy Chinese adults were enrolled in the trial. Four loci in VDR gene (rs2228570 [FokI], rs2189480, rs2239179 and rs7975232[ApaI]) were genotyped by TaqMan probe assays. Obesity indexes including BMI, WC, BFP and triceps skinfold thickness were used to evaluate the relationship to the VDR SNPs. Multiple logistic regression, linear regression and general multifactor dimensionality reduction (GMDR) were performed to analyze the correlation of VDR gene and obesity indexes.

Results

None of the VDR SNPs were associated with BMI and WC, the C allele of FokI and the T allele of ApaI were associated with an increase in BFP (β = 0.069,P = 0.007; β = 0.087, P = 0.022 respectively); the G allele of rs2239179 and the T allele of ApaI were associated with an increase in triceps skin fold thickness (β = 0.074, P = 0.001; β = 0.122, P < 0.001 respectively). In regards to adiposity-related metabolic parameters, we found that the GT genotype of ApaI was associated with higher level of total cholesterol (TC) (P = 0.013) and Low-density lipoprotein cholesterol (LDL-C) (P = 0.001).

Conclusions

Though we failed to prove that VDR SNPs were in correlation with BMI and WC, we did establish the association between VDR variants and BFP, as well as triceps skinfold thickness. Data obtained suggested that the VDR variants play an important role in regulating adipose tissue activity and adiposity among Han Chinese.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-1027-2) contains supplementary material, which is available to authorized users.