No association of vitamin D receptor gene BsmI polymorphisms with calcium oxalate stone formation

Genetic Polymorphisms and Kidney Stones Around the Globe: A Systematic Review and Meta-Analysis

Objective: This study explores associations between recurrent kidney stones and genetic polymorphisms.

Methods: Meta-analysis of polymorphisms in renal stone cases versus control groups. Four electronic databases (PubMed, SCOPUS, EMBASE, and Web of Science) were searched up to 30 May 2021, using the keywords: “kidney stone” or “kidney calculi,” or “urolithiasis” or “nephrolithiasis” or “urinary calculi” and “genome” or “genetic” or “mutation” or “single nucleotide polymorphism.” Forrest plots, ORs, 95% CI, Chi-square (χ2)-test, and index of heterogeneity (I2) were calculated. Only studies with Newcastle–Ottawa scale (NOS) ≥ 6 were included for quality control, and Funnel, Begg’s, and Eager’s plots assessed publication bias. PROSPERO: CRD42022250427.

Results: Among 7,671 searched articles, 72 were included. Polymorphisms in VDR (OR: 1.20; 95% CI: 1.06–1.36), CASR (OR = 1.24; 95% CI: 1.01–1.52), Osteopontin (OR = 1.38; 95% CI: 1.09–1.74), and Urokinase genes (OR = 1.52; 95% CI: 1.02–2.28) showed a significant association with risk of urinary stone formation, while Klotho gene showed a protective effect (OR = 0.75; 95% CI: 0.57–0.99). The VDR gene polymorphism was frequent in Asians, whereas CASR polymorphism was frequent in European and North American populations.

Conclusion: Multifactorial nature of the stone formation, emphasizing the role of environmental factors, might explain contradictory results in the literature. While polymorphisms in VDR, CASR, Osteopontin, and Urokinase genes were associated with urinary stone formation, the Klotho gene showed a protective effect.

Vitamin D receptor gene polymorphisms and susceptibility to urolithiasis: a meta-regression and meta-analysis

BACKGROUND

The currently available data with respect to the association between vitamin D receptor (VDR) gene polymorphism and risk to urolithiasis are inconclusive and inconsistent. Hence, an exhaustive meta-analysis can solve the discrepancies and provide a hint for upcoming investigations. Herein, a meta-analysis was carried out to attain a conclusive estimate of the association between VDR gene single nucleotide polymorphisms (SNPs) and urolithiasis risk.

METHODS

The major databases, including ISI Web of science, Scopus, and PubMed/MEDLINE were searched systematically from until June 2020 to retrieve all relevant studies. Association between VDR gene polymorphisms, including FokI (rs2228570), TaqI (rs731236), BsmI (rs1544410), and ApaI (rs7975232), and urolithiasis risk was evaluated using pooled odds ratio (OR) and their corresponding 95% confidence interval (CI). Additionally, to seek for the potential source of heterogeneity, meta-regression analyses were exerted.

RESULTS

Literature search led to finally finding of 33 studies evaluating the VDR gene SNPs and urolithiasis risk. It was observed that none of the four SNPs were significantly associated with urolithiasis predisposition. However, subgroup analysis confirmed higher risk of urolithiasis in East-Asian and Caucasian population with ApaI and TaqI gene polymorphism. The analyses of sensitivity acknowledged the results stability.

CONCLUSION

Although this meta-analysis did not support the association of FokI, TaqI, BsmI, and ApaI in the overall polled analysis, it suggests that ApaI and TaqI SNPs is associated with increased risk of urolithiasis in East-Asian and Caucasians populations.

Genetics of kidney stone disease

Kidney stone disease (nephrolithiasis) is a common problem that can be associated with alterations in urinary solute composition including hypercalciuria. Studies suggest that the prevalence of monogenic kidney stone disorders, including renal tubular acidosis with deafness, Bartter syndrome, primary hyperoxaluria and cystinuria, in patients attending kidney stone clinics is ∼15%. However, for the majority of individuals, nephrolithiasis has a multifactorial aetiology involving genetic and environmental factors. Nonetheless, the genetic influence on stone formation in these idiopathic stone formers remains considerable and twin studies estimate a heritability of >45% for nephrolithiasis and >50% for hypercalciuria. The contribution of polygenic influences from multiple loci have been investigated by genome-wide association and candidate gene studies, which indicate that a number of genes and molecular pathways contribute to the risk of stone formation. Genetic approaches, studying both monogenic and polygenic factors in nephrolithiasis, have revealed that the following have important roles in the aetiology of kidney stones: transporters and channels; ions, protons and amino acids; the calcium-sensing receptor (a G protein-coupled receptor) signalling pathway; and the metabolic pathways for vitamin D, oxalate, cysteine, purines and uric acid. These advances, which have increased our understanding of the pathogenesis of nephrolithiasis, will hopefully facilitate the future development of targeted therapies for precision medicine approaches in patients with nephrolithiasis.

Relationship Between the ApaI (rs7975232), BsmI (rs1544410), FokI (rs2228570), and TaqI (rs731236) Variants in the Vitamin D Receptor Gene and Urolithiasis Susceptibility: An Updated Meta-Analysis and Trial Sequential Analysis

The relationship between urolithiasis and vitamin D receptor (VDR) gene variants is still under debate according to the available published literature. To assess correlations between VDR gene variants ApaI (rs7975232), BsmI (rs1544410), FokI (rs2228570), and TaqI (rs731236) and urolithiasis susceptibility, we performed the present study through meta-analysis. The PubMed, Cochrane Library, China National Knowledge Infrastructure, EMBASE, Web of Science, and Wanfang databases were searched to retrieve qualified case-control studies. Finally, 31 reports were selected for the present meta-analysis. The results demonstrated that the VDR gene TaqI TT genotype was related to decreased risk of urolithiasis in the overall population (TT vs. Tt+tt: P = 0.011, OR = 0.824, 95% CI = 0.709–0.957). In ethnicity subgroup analysis, we found that the TaqI variant was obviously correlated to urolithiasis risk among Asians and Caucasians (P < 0.05). Additionally, significant urolithiasis risk was identified in adults. However, the FokI, BsmI, and ApaI variants did not have an increased risk of developing urolithiasis. Trial sequential analysis results were on a sufficiently large number of participants and did not require more research to confirm associations. Our research suggested that the VDR gene variant TaqI was correlated with urolithiasis susceptibility and that the t-allele might be the risk gene and T-allele the protective gene in VDR TaqI variant.

Association of vitamin D receptor gene polymorphisms and risk of urolithiasis: results of a genetic epidemiology study and comprehensive meta-analysis

Polymorphisms of vitamin D receptor (VDR) gene have been associated with risk of urolithiasis, but, with inconsistent results and lack data from Pakistani population. Therefore, after including our indigenous study data, a comprehensive meta-analysis was performed to provide an evidence-based estimate of any association between VDR polymorphisms and urolithiasis risk. A total of 483 Pakistani subjects, comprising 235 urolithiasis patients and 248 healthy controls, were genotyped for 6 VDR polymorphisms. Additionally, a systematic literature search with subsequent meta-analysis was conducted and pooled odds ratios (ORs) were used to determine the strength of any existent associations. Trial sequential analysis (TSA) was also performed. Results revealed no significant association of any VDR polymorphism and urolithiasis risk in indigenous Pakistani patients. However, meta-analysis of 29 relevant studies indicated that VDR FokI polymorphism significantly increased the risk of urolithiasis in allelic (f vs. F: OR = 1.13; 95% CI = 1.05-1.22; p ≤ 0.01) and recessive (ff vs. FF + Ff: OR = 1.20; 95% CI = 1.05-1.38; p = 0.01) models with no significant heterogeneity. No associations were evident for VDR ApaI, BsmI and TaqI polymorphic variants and urolithiasis risk after correction for multiple testing. Subgroup analysis by ethnicity suggested significant association for FokI variant among Asians. The TSA results demonstrated that the evidence reflecting association of FokI polymorphism and urolithiasis risk was sufficient and conclusive. In conclusion, this meta-analysis suggests that VDR FokI polymorphism is significantly associated with urolithiasis risk, especially in Asians, whereas ApaI, BsmI and TaqI polymorphisms are not associated.

Effects of vitamin D receptor polymorphisms on urolithiasis risk: a meta-analysis

Background

Several studies analyzed the associations of Vitamin D receptor (VDR) polymorphisms with urolithiasis risk in different ethnic groups. However, the results were inconclusive. To evaluate a more precise estimation of the relationship, a meta-analysis was performed.

Methods

Pubmed, EMBASE, Wanfang Database, China National Knowledge Infrastructure (CNKI) and Weipu Database were searched. Data were extracted independently by two investigators. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

Results

Twenty-three case–control studies were included in this meta-analysis. Significant associations between ApaI, BsmI, FokI, and TaqI polymorphisms and urolithiasis risk were observed. However, sensitivity analyses for BsmI and FokI polymorphisms indicated that the results were not reliable and credible. In addition, there was a significant association of the ApaI-TaqI haplotype with urolithiasis risk.

Conclusions

This meta-analysis suggested that ApaI and TaqI polymorphisms in VDR gene were associated with urolithiasis risk.

Association of vitamin D receptor (Fok-I) polymorphism with the clinical presentation of calcium urolithiasis

OBJECTIVE

To investigate the effect of the vitamin D receptor (VDR) FokI polymorphism on the clinical presentation of calcium urolithiasis, as a FokI polymorphism in the VDR gene was recently reported to be associated with calcium metabolism disorders.

PATIENTS, SUBJECTS AND METHODS

In all, 235 patients with calcium urolithiasis and 231 age- and sex-matched healthy controls were recruited from Kaohsiung Medical University Hospital between June 2003 and February 2005. Clinical information on the age at first onset, stone episodes, stone severity and presence of family history were collected from patients with stones. Any VDR FokI polymorphism was detected using polymerase chain reaction-based restriction analysis.

RESULTS

The frequency of VDR FokI genotypes between the patients and the healthy controls was not significantly different. However, among patients, those with the FF genotype had a significantly higher risk of having more stone episodes (adjusted odds ratio 2.15, 95% confidence interval 1.02-4.54, P = 0.044) and were younger at the first onset (3.23, 1.08-9.63, P = 0.036) than those with the ff genotype.

CONCLUSION

The VDR FokI polymorphism might be important in the clinical presentation of patients with calcium urolithiasis, especially for the frequency of stone episodes and age at first onset, although it is not associated with the formation of stones.

Vitamin D receptor gene polymorphisms in patients with urolithiasis

Urolithiasis is a multifactorial disease, the onset and severity of which is influenced by both genetic and environmental factors. This study represents an investigation of the role of vitamin D receptor (VDR) gene polymorphisms (ApaI, BsmI, and TaqI) and combined genotypes in urolithiasis in a Turkish population. We studied 110 patients with urinary stones and 150 control subjects. The polymorphic regions were amplified using polymerase chain reaction, followed by digestion with restriction enzymes BsmI, ApaI, and TaqI, and analyzed electrophoretically. Genotype and allele frequencies were calculated, and the association with urolithiasis, family history, and recurrence of stone was investigated. Our data provide no evidence for an association between urolithiasis and VDR ApaI, BsmI, and TaqI genotypes. We also analyzed the effects of VDR ApaI, BsmI, and TaqI genotypes in combination; the "GTT" VDR haplotype, constructed from three adjacent restriction fragment length polymorphisms was overrepresented among the urolithiasis patients. However, no significant differences between heterozygous carriers (OR 1.302; 95% CI 0.527-3.215) and homozygous carriers (OR 3.39; 95% CI 0.719-15.985) were observed in our study population. A significant association was found only between the ApaI polymorphism and family history (P=0.017; chi (2)=5.657). Our data indicate that the VDR ApaI, BsmI, and TaqI polymorphisms do not confer a significant risk for urolithiasis.

Association between vitamin D receptor gene polymorphisms and fasting idiopathic hypercalciuria in recurrent stone-forming patients

OBJECTIVES

To investigate the association between fasting idiopathic hypercalciuria (IHc), defined as IHc in the fasting state associated with normal parathyroid function, and ApaI, BsmI, and FokI polymorphisms of the vitamin D receptor (VDR) gene in 159 hypercalciuric recurrent stone formers. IHc contributes to the formation of calcium kidney stones in more than one half of reported cases.

METHODS

We examined 62 patients with fasting IHc (24 women, mean age 42.8 +/- 11.1 years, body mass index 25.7 +/- 4.8 kg/m2), 97 patients with absorptive IHc (41 women, mean age 43.5 +/- 10.8 years, body mass index 26.1 +/- 4.4 kg/m2), and 124 healthy control subjects (52 women, mean age 41.9 +/- 10.4 years, body mass index 25.4 +/- 5.1 kg/m2) without a history of nephrolithiasis and without IHc. The bone mass density and VDR genotype and haplotype frequencies were determined in the studied populations.

RESULTS

A reduced bone mass density was observed in fasting IHc patients compared with absorptive IHc patients (P = 0.009) and control subjects (P = 0.006). The prevalence of ApaI and BsmI VDR genotypes and alleles in patients with fasting IHc was significantly different statistically (P <0.05) from that observed in patients with absorptive IHc and control subjects, and the ba haplotype was overrepresented in these patients. No statistically significant difference in the distribution of FokI VDR genotypes and alleles was found between the studied groups.

CONCLUSIONS

Our results suggest a genetic association between 3' VDR alleles, fasting IHc, and reduced bone mass density in patients with recurrent stone formation.

Association of vitamin D receptor genotypes with calcium excretion in nephrolithiatic subjects in northern India

Our objective was to investigate the association between the vitamin D receptor (VDR) allelic variants (Bsm I and Fok I) and nephrolithiasis in northern India. A total of 150 nephrolithiatic patients and 100 age and sex matched controls were enrolled for study. A 10 ml blood sample was obtained for biochemical analysis and DNA isolation. In addition, 24 h urine samples were obtained from each patient for the estimation of calcium and creatinine. PCR was performed for the Bsm I and Fok I VDR variants. The association between Bsm I and Fok I VDR polymorphism and nephrolithiasis was investigated after digestion with restriction enzymes (3 U). The product was analysed on 3% agarose gel for Bsm I and 15% polyacrylamide gel for Fok I allelic variants. We did not observe any significant differences in the prevalence of either the Bsm I or Fok I VDR genotypes between stone formers and controls. The B allele was found to be more prevalent in hypercalciuric patients compared to controls and nephrolithiatic subjects. The subjects with the bb genotype exhibited a higher calcium excretion than the BB genotype. Patients with the F allele were also found to excrete higher urinary calcium. VDR genotypes may be associated with increased calcium excretion in hypercalciuric nephrolithiatic subjects.

Association between vitamin D receptor gene polymorphisms and tubular citrate handling in calcium nephrolithiasis

OBJECTIVES

Hypocitraturia is a risk factor for calcium nephrolithiasis. 1,25(OH)2D3 influences renal citrate handling and enhances citraturia. The aim of this study was to evaluate the relationship between vitamin D receptor (VDR) allelic variant and urinary citrate excretion in recurrent stone formers (SF) patients.

DESIGN

Case-control study.

SUBJECTS

A total of 220 recurrent calcium oxalate SF patients and 114 healthy control (C) subjects were enrolled for this study. Subjects with urinary tract infections, hyperparathyroidism, cystinuria >70 micromol/24 h, gouty diathesis, renal tubular acidosis, renal failure, chronic diarrhoeal states, intake of thiazide diuretics, angiotensin-converting enzyme (ACE)-inhibitors, glucocorticoids or oestrogens were excluded. A standard constant diet was given for 7 days. The 24-h urinary citrate excretion and the active tubular reabsorption of filtered citrate (Rcit) were evaluated. Hypocitraturia was defined as a urinary citrate excretion lower than 1.7 mmol day-1. Stone formers patients and C were genotyped for BsmI and TaqI VDR alleles. Contingency table chi-square tests were used to compare genotype frequencies in hypocitraturic SF patients, normocitraturic SF and C.

RESULTS

The prevalence of hypocitraturia in SF patients was 32.7% (72 of 200). Hypocitraturia in these patients resulted from excessive Rcit of a normal load of citrate. We found a different distribution (P < 0.05) of BsmI and TaqI VDR genotypes in hypocitraturic SF patients compared with normocitraturic SF and C. In particular, the prevalence of bb and TT VDR genotypes in hypocitraturic SF was significantly higher than in normocitraturic SF and C.

CONCLUSIONS

These results point to a genetic association between BsmI and TaqI VDR polymorphisms and idiopathic hypocitraturia in calcium-oxalate recurrent SF patients.