Vitamin D Receptor Genetic Polymorphism Is Significantly Associated with Risk of Type 2 Diabetes Mellitus in Chinese Han Population

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

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

Association of vitamin D receptor gene rs739837 polymorphism with type 2 diabetes and gestational diabetes mellitus susceptibility: a systematic review and meta-analysis

Background

Increasing evidence shows that genetic variants of genes in the diabetes mellitus (DM) metabolic pathway, such as the vitamin D receptor (VDR) gene rs739837 polymorphism, increase the risk of DM susceptibility. However, the findings have been inconsistent. The present study was performed to evaluate the association of VDR gene rs739837 and type 2 diabetes (T2DM) or gestational diabetes mellitus (GDM) risk.

Methods

A comprehensive meta-analysis and a subgroup analysis were conducted to assess the association between VDR rs739837 and T2DM or GDM among five genetic models (dominant, recessive, homozygote heterozygote, and allele models) using a fixed or random model.

Results

The meta-analysis included 9 studies. In the overall analysis, the results showed that VDR rs739837 was associated with an increased risk of T2DM or GDM in the allele model (T vs. G: OR = 1.088; 95% CI: 1.018–1.163; P = 0.012) and dominant model (TT + GT vs. GG: OR = 1.095; 95% CI: 1.001–1.197; P = 0.047). In the subgroup analysis, VDR rs739837 was also associated with an increased risk of T2DM in the allele model (T vs. G: OR = 1.159; 95% CI: 1.055–1.273; P = 0.002) and dominant model (TT + GT vs. GG: OR = 1.198; 95% CI: 1.048–1.370; P = 0.008). However, VDR rs739837 was not associated with GDM.

Conclusions

Significant associations were found between the VDR rs739837 polymorphism and T2DM susceptibility, but not with GDM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00688-x.

Exploring the relationship between vitamin D and leptin hormones in type 2 diabetes mellitus patients from Kuwait

BACKGROUND

Type 2 diabetes mellitus (T2DM) and obesity are prevalent in Kuwait. Vitamin D (VD) deficiency and leptin resistance are risk factors for both disorders. A correlation between the two risk factors has been suggested albeit inconsistently reported. Our objective was to determine the effect and association of VD and leptin levels and their related common variants with T2DM.

METHODS

This case-control study included 203 Kuwaiti T2DM patients and 162 healthy Kuwaiti controls. Leptin and VD levels were measured using enzyme linked immunosorbent assays. Genotyping of LEP rs7799039, LEPR rs1137101, VDR rs2228570 and rs731236 was performed using Taqman genotyping assays.

RESULTS

Leptin levels were higher in T2DM patients than controls, but vitamin D levels did not differ. No correlation was found between the levels of the two hormones. VDR rs731236G associated with T2DM risk (Odds ratio 1.66, p=0.0008). VDR haplotype analysis revealed GG/AA, GA/AA or GG/AG to associate with T2DM risk (p=0.01) and increased risk of diabetic neuropathy (p=0.002). VDR rs2228570GG associated with leptin levels in T2DM (p=0.01). Effect of LEP rs7799039 on leptin (p=0.01) and VD levels (p=0.02) was only evident in healthy controls.

CONCLUSIONS

VDR rs731236G is associated with T2DM risk in Kuwait, and a VDR haplotype of a less active, low expressing VDR is associated with T2DM and diabetic neuropathy risk. Common variants in leptin and VD related genes appear to mediate the suggested positive correlation of both hormones however their influence is disrupted in T2DM.

Vitamin D Metabolic Pathway Genes Polymorphisms and Their Methylation Levels in Association With Rheumatoid Arthritis

Abnormal vitamin D metabolism is involved in the pathogenesis of rheumatoid arthritis (RA). In this study, we evaluated the association of single nucleotide polymorphisms (SNPs) and methylation levels in vitamin D metabolic pathway genes with RA susceptibility. Ten SNPs in vitamin D metabolic pathway genes (CYP2R1, CYP24A1, VDR, CYP27B1) were genotyped in 477 RA patients and 496 controls by improved multiple ligase detection reaction (iMLDR). The methylation levels of the promoter regions of these genes were detected in 122 RA patients and 123 controls using Illumina Hiseq platform. We found that the CYP2R1 rs1993116 GA genotype, CYP27B1 rs4646536 GA genotype, rs4646536 A allele frequencies were significantly increased in RA patients when compared to controls. The decreased risk of rs1993116, rs4646536 was found under the dominant mode in RA patients. However, no significant association was found between CYP2R1 rs7936142, rs12794714, CYP24A1 rs2762934, rs6068816, rs2296239, rs2296241, VDR rs11574129, rs3847987 polymorphism, and RA susceptibility. The VDR, CYP27B1 methylation levels in RA patients were significantly lower than those in controls, while CYP2R1, CYP24A1 methylation levels were not associated with RA. There were no statistical associations between CYP2R1, CYP24A1, VDR, CYP27B1 methylation levels and their respective genotype in RA patients. In addition, plasma 25OHD level in RA patients was significantly lower than that in healthy controls. In summary, our results showed that CYP2R1, CYP27B1 genetic variations were associated with the genetic background of RA, while altered VDR, CYP27B1 methylation levels were related to the risk of RA.

Evaluation of association studies and a systematic review and meta-analysis of VDR polymorphisms in type 2 diabetes mellitus risk

Numerous original studies and 4 published meta-analyses have reported the association between the Vitamin D receptor (VDR) BsmI, FokI, ApaI, and TaqI polymorphisms and type 2 diabetes mellitus (T2DM) risk. However, the results were inconsistent. Therefore, an updated meta-analysis was performed to further explore these issues.To further explore the association between the VDR BsmI, FokI, ApaI, and TaqI polymorphisms and T2DM risk.PubMed, EMBASE, Scopus, and Wanfang databases were searched. The following search strategy were used: (VDR OR vitamin D receptor) AND (polymorphism OR variant OR mutation) AND (diabetes OR mellitus OR diabetes mellitus). Pooled crude odds ratios with 95% confidence intervals were applied to evaluate the strength of association in 5 genetic models. Statistical heterogeneity, the test of publication bias, and sensitivity analysis were carried out using the STATA software (Version 12.0). To evaluate the credibility of statistically significant associations, we applied the false-positive report probabilities (FPRP) and Bayesian false discovery probability (BFDP) test.Overall, the VDR BsmI polymorphism was associated with a significantly decreased T2DM risk in Asians; the VDR FokI polymorphism was associated with a significantly decreased T2DM risk in Asians, African countries, and Asian countries; the VDR ApaI polymorphism was associated with a significantly decreased T2DM risk in Caucasians and North American countries.On the VDR ApaI polymorphism, a significantly increased T2DM risk was found in a mixed population. However, when we further performed a sensitivity analysis, FPRP, and BFDP test, less-credible positive results were identified (all FPRP > 0.2 and BFDP > 0.8) in any significant association.In summary, this study strongly indicates that all significant associations were less credible positive results, rather than from true associations.

The influence of VDR polymorphisms on the type 2 diabetes susceptibility in Chinese: an interaction with hypertriglyceridemia

Evidence shows that mutations in vitamin D receptor (VDR) have been linked with an increased risk of type 2 diabetes (T2D). However, the interaction effect between VDR variants and environmental factors on the T2D susceptibility remained unclear. Therefore, the current study was conducted to explore the joint effect of VDR polymorphisms and serum triglyceride level on T2D. A total of 2017 participants were included in the cross-sectional study. Taqman probe assays were applied to rs3847987 and rs739837 genotyping. Multiple logistic regression and general linear model were used to examine the effect of interaction between VDR variants and TG on T2D susceptibility and fasting serum glucose, respectively. The results showed that rs739837 polymorphism was significantly associated with an increased risk of T2D under the dominant model (OR = 1.30, 95% CI 1.02-1.66), after adjusting for potential risk factors. Meanwhile, there was a significant additive interaction between rs3847987 and hypertriglyceridemia (synergy index [SI]: 2.98, 95% CI: 1.23-7.23) and between rs739837 and hypertriglyceridemia (SI: 2.36, 95% CI: 1.05-5.31) on T2D susceptibility. Additionally, a significant linear association between fasting glucose and rs3847987 had been found at high triglyceride level (> 1.90 mmol/L) with an inversely concentration-dependent manner. The study provided further evidence that rs739837 and high level of triglyceride were both associated with higher T2D susceptibility in Chinese population. Additionally, the detrimental effect of VDR variants on T2D could be modified by hypertriglyceridemia status.

Association of Vitamin D Receptor Gene Polymorphisms With the Evolution of MODY Diabetes: Study in Tunisian Patients

Vitamin D (VD) cannot be considered as a true vitamin, but rather as a hormone, which exerts its action via a vitamin D receptor (VDR). Many genes have been shown to be involved in the evolution of diabetes in various populations, such as the vitamin D receptor gene. The aim of our study was to investigate if BsmI, TaqI, ApaI, FokI, and Tru9I, polymorphisms of VDR gene have an impact on MODY diabetes and its clinical aspects in a Tunisian population. A total of 95 patients and 153 controls were genotyped using PCR-RFLP. The comparison of the allelic and genotypic frequencies of the five polymorphisms between MODY subjects and control groups revealed the association of MODY diabetes with TaqI, Tru9I and BsmI polymorphisms and no significant differences were observed in the distributions for the ApaI and FokI polymorphisms. After stratification with biochemical and clinical parameters and TaqI, Tru9I and BsmI polymorphisms, we found an association between the three SNPs and different parameters such as age of diagnosis, therapy, hsCRP and HDL-C levels. Our results revealed that TaqI, Tru9I and BsmI polymorphisms may be more related to the progression of MODY diabetes. The possible role of vitamin D in the pathogenesis of MODY is far from being completely understood. Further knowledge on this issue may identify new candidate targets in the treatment and prevention of the disease. Our findings suggest that the TaqI, Tru9I and BsmI polymorphisms may be more related to the progression of MODY diabetes.

Association of vitamin D receptor gene polymorphisms with gestational diabetes mellitus-a case control study in Wuhan, China

BACKGROUND

Gestational diabetes mellitus (GDM) increased risk of perinatal complications for both the women and the fetuses. The association between the vitamin D receptor (VDR) gene polymorphism and GDM has not been thoroughly investigated in Chinese pregnant women. Therefore, we aimed to determine whether VDR gene single nucleotide polymorphisms (SNPs) rs154410, rs7975232, rs731236, rs2228570 and rs739837 contribute to GDM risk in Wuhan, China. Moreover, we aimed to explore their combined effects on the risk of GDM.

METHODS

Pregnant women who had prenatal examinations at 24 to 28 weeks' gestation in our hospital from January 15, 2018 to March 31, 2019 were included in this case-control study. After exclusion, a total of 1684 pregnant women (826 GDM patients and 858 non-diabetic controls) were recruited. The clinical information and blood samples were collected by trained interviewers and nurses. Genotyping of candidate SNPs was conducted on the Sequenom MassARRAY platform. Statistical analyses including t-test, ANOVA, chi-square test and logistic regression were performed to the data with SPSS Software to evaluate differences in genotype distribution and associations with GDM risk. Multifactor dimensionality reduction method was used to explore the gene-gene interactions on the risk of GDM.

RESULTS

Differences in age, pre-pregnancy BMI, family history of diabetes and previous history of GDM between the case and control groups were statistically significant (P < 0.05), whereas no significant differences were found in height, gravidity, parity, and age of menarche (P > 0.05). There were no significant differences at genotype distributions of the examined VDR gene SNPs (P > 0.05). After adjusting by age, pre-pregnancy BMI, family history of diabetes, the results of logistic regression analysis showed no associations of the five SNPs with GDM in all the four genotype models(P > 0.05). Furthermore, there were no gene-gene interactions on the GDM risk among the five examined VDR gene SNPs.

CONCLUSIONS

The VDR gene SNPs rs154410, rs7975232, rs731236, rs2228570 and rs739837 showed neither significant associations nor gene-gene interactions with GDM in Wuhan, China.

Vitamin D Receptor gene polymorphisms and susceptibility to type 2 diabetes: evidence from a meta-regression and meta-analysis based on 47 studies

Background

Evidence from various studies suggest that vitamin D receptor (VDR) gene polymorphisms are associated with type 2 diabetes (T2D); However, these results have been disputable. Here we conducted a meta-analysis to comprehensively evaluate the effect of VDR gene polymorphisms and susceptibility to T2D.

Methods

All relevant studies reporting the association between VDR gene polymorphisms and susceptibility to T2D published up to August 2020 were identified by comprehensive systematic database search in web of science, Scopus, and Medline. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to measure strength of association. The methodological quality of each study was assessed according to the Newcastle-Ottawa Scale. Subgroup and meta-regression analysis were also performed.

Results

A total of 47 case-control studies were included in this meta-analysis. The overall population results revealed a significant association between FokI, and BsmI (heterozygote model) polymorphisms and T2D in the overall analysis. However, no association was found with the TaqI and ApaI polymorphisms. Moreover, the pooled results of subgroup analysis by ethnicity suggested significant association between FokI, TaqI, and BsmI polymorphisms and T2D in some subgroups. Meta-regression analyses indicated that none of the publication year, ethnicity, and genotyping method were the source of heterogenicity in all four polymorphisms.

Conclusions

This meta-analysis suggested a significant association between VDR gene FokI, and BsmI (heterozygote model) polymorphisms and T2D susceptibility in overall population and ethnic-specific analysis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-020-00704-z.

Vitamin D Level and Vitamin D Receptor Genetic Variation Were Involved in the Risk of Non-Alcoholic Fatty Liver Disease: A Case-Control Study

BACKGROUND

It has been demonstrated that vitamin D receptor (VDR), a key gene in the metabolism of vitamin D (VD), may affect the development of Non-alcoholic fatty liver disease (NAFLD) by regulating VD level and its biological effects.

OBJECTIVES

To investigate the effects of serum VD level, VDR variation, and a combination of VDR SNP and environmental behavior factor on the risk of NAFLD.

METHODS

A total of 3023 subjects from a community in Nanjing were enrolled, including 1120 NAFLD cases and 1903 controls. Serum 25(OH)D₃ levels were measured and eight single nucleotide polymorphisms (SNPs) in VDR gene were genotyped.

RESULTS

Logistic regression analyses indicated that VD sufficiency and VD insufficiency were significantly associated with a low risk of NAFLD (all P<0.05; all P_trend<0.05, in a locus-dosage manner). After adjusting for gender and age, VDR rs2228570-A and rs11168287-A alleles were all reduced the risk of NAFLD (all P_FDR=0.136, in dominant model; P_trend =0.039, combined effects in a locus-dosage manner). The protective effects of two favorable alleles were more evident among subjects ≤40 years, non-hypertension, non-hyperglycemia and non-low high density lipoprotein-cholesterol (all P<0.05). The area under the receiver operating curve of the combination of VDR SNP and exercise time for assessing NAFLD risk was slightly higher than that of only including exercise time or neither (all P<0.05).

CONCLUSION

High serum VD levels and VDR variants (rs2228570-A and rs11168287-A) might contribute to a low risk of NAFLD in Chinese Han population. The inclusion of VDR SNP and exercise time could improve the efficiency in assessment of NAFLD risk, which might provide a novel perspective for early screening and preventing NAFLD.

Vitamin D pathway-related gene polymorphisms and their association with metabolic diseases: A literature review

PURPOSE

Given that the relationship between vitamin D status and metabolic diseases such as obesity and type 2 diabetes (T2D) remains unclear, this review will focus on the genetic associations, which are less prone to confounding, between vitamin D-related single nucleotide polymorphisms (SNPs) and metabolic diseases.

METHODS

A literature search of relevant articles was performed on PubMed up to December 2019. Those articles that had examined the association of vitamin D-related SNPs with obesity and/or T2D were included. Two reviewers independently evaluated the eligibility for the inclusion criteria and extracted the data. In total, 73 articles were included in this review.

RESULTS

There is a lack of research focusing on the association of vitamin D synthesis-related genes with obesity and T2D; however, the limited available research, although inconsistent, is suggestive of a protective effect on T2D risk. While there are several studies that investigated the vitamin D metabolism-related SNPs, the research focusing on vitamin D activation, catabolism and transport genes is limited. Studies on CYP27B1, CYP24A1 and GC genes demonstrated a lack of association with obesity and T2D in Europeans; however, significant associations with T2D were found in South Asians. VDR gene SNPs have been extensively researched; in particular, the focus has been mainly on BsmI (rs1544410), TaqI (rs731236), ApaI (rs7975232) and FokI (rs2228570) SNPs. Even though the association between VDR SNPs and metabolic diseases remain inconsistent, some positive associations showing potential effects on obesity and T2D in specific ethnic groups were identified.

CONCLUSIONS

Overall, this literature review suggests that ethnic-specific genetic associations are involved. Further research utilizing large studies is necessary to better understand these ethnic-specific genetic associations between vitamin D deficiency and metabolic diseases.

Leveraging Nuclear Receptors as Targets for Pathological Ocular Vascular Diseases

Vasculogenesis and angiogenesis are physiological mechanisms occurring throughout the body. Any disruption to the precise balance of blood vessel growth necessary to support healthy tissue, and the inhibition of abnormal vessel sprouting has the potential to negatively impact stages of development and/or healing. Therefore, the identification of key regulators of these vascular processes is critical to identifying therapeutic means by which to target vascular-associated compromises and complications. Nuclear receptors are a family of transcription factors that have been shown to be involved in modulating different aspects of vascular biology in many tissues systems. Most recently, the role of nuclear receptors in ocular biology and vasculopathies has garnered interest. Herein, we review studies that have used in vitro assays and in vivo models to investigate nuclear receptor-driven pathways in two ocular vascular diseases associated with blindness, wet or exudative age-related macular degeneration, and proliferative diabetic retinopathy. The potential therapeutic targeting of nuclear receptors for ocular diseases is also discussed.

Variants rs1544410 and rs2228570 of the vitamin D receptor gene and glycemic levels in adolescents from Northeast Brazil

Introduction

Objective: to verify the association of serum concentrations of 25-hydroxyvitamin D and glycemic levels with the genetic variants rs1544410 and rs2228570 of the VDR gene in adolescents from the Northeast region of Brazil. Materials and methods: a cross-sectional epidemiological study with 208 adolescents from public schools in the city of João Pessoa (Paraíba, Brazil) between 15 and 19 years of age. Blood samples were collected for DNA extraction and analysis of polymorphisms rs1544410 and rs2228570, as well as biochemical analyses (25-hydroxyvitamin D, parathyroid hormone, calcium and glycemia). Results: the mean age was 17.7 (± 1.14) years. Half of adolescents had sufficient serum levels of 25-hydroxyvitamin D and the other half had insufficient/deficient vitamin. The most frequent genotypic distribution was bb and Ff and of lesser frequency BB and ff. There was a significant relationship between the genotypes of rs1544410 and glycemia values (p = 0.049) in the relationships between the genotypes BBxbb (p = 0.012) and Bbxbb (p = 0.037); (p = 0.036, OR = 2.15, 95% CI = 1.05-4.41), and in the BB+Bb group analysis when compared to the bb (p = 0.025, OR = 1.89, 95% CI = 1.08-3.29) presented higher risk of glycemia above the median. On the other hand, when Bb+bb was analyzed in relation to BB, adolescents had a greater chance of blood glucose below the median (p = 0.025, OR = 0.66, CI = 0.47-0.95). Conclusion: this study showed a significant relation of glycemia with the distribution of rs1544410 polymorphism genotypes.

Diminished 25-OH vitamin D3 levels and vitamin D receptor variants are associated with susceptibility to type 2 diabetes with coronary artery diseases

Background

Role of plasma vitamin D and genetic variants of its receptor (VDR) in susceptibility to different diseases has been documented. Various studies in different populations have been highlighted strong associations with diabetes and cardiovascular diseases. Vitamin D deficiency has been linked with the development of type 2 diabetes (T2D) and the onset of coronary artery diseases (CAD). However, the role of vitamin D in predisposition to CAD in patients with T2D is ill‐defined.

Materials and Methods

We enrolled 674 Chinese T2D patients, and based on clinical phenotype, patients were further categorized into patients with (n = 138) or without coronary artery disease (n = 536). Five hundred twenty‐one healthy subjects from similar geographical areas, free from diabetic or coronary disorders, were enrolled as controls. Serum levels of 25‐OH vitamin D were quantified by ELISA. Common VDR (FokI, TaqI, BsmI, and ApaI) polymorphisms were genotyped by polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP).

Results

Patients with T2D displayed lower levels of 25‐OH vitamin D compared with healthy controls. Furthermore, T2D patients with CAD clinical phenotype had the lowest levels of vitamin D. Prevalence of FokI and TaqI mutants was significantly higher in diabetic patients when compared to controls. Interestingly, Tt genotype was more frequent in the artery disease group in comparison with T2D patients without heart involvement. Combined analysis of VDR polymorphisms and serum levels of vitamin D revealed a significant role in predisposition to T2D with or without CAD.

Conclusions

Lower vitamin D levels and variants of VDR polymorphisms (FokI and TaqI) are associated with susceptibility to T2D and clinical manifestation.

Associations of Vitamin D Receptor Single Nucleotide Polymorphisms with Susceptibility to Systemic Sclerosis

BACKGROUND

This study aims to evaluate whether the Vitamin D receptor (VDR) gene polymorphisms were associated with systemic sclerosis (SSc) in a Chinese Han population.

METHODS

Using a hospital-based case-control study including 100 SSc patients and 100 healthy controls. Single nucleotide polymorphisms (SNPs) in the VDR region were genotyped by the improved multiplex ligase detection reaction (i MLDR) method. Haplotypes were also constructed after linkage disequilibrium (LD) analysis.

RESULTS

Eight SNPs (rs731236 (TaqI), rs2228570 (FokI), rs7975232 (ApaI), rs1544410 (BsmI), rs11574010 (Cdx2), rs739837 (BglI), rs757343 (Tru9I) and rs11168267) were included. There were significant differences between SSc patients and healthy individuals in ApaI and BglI genotype (both adjusted p = 0.008). Through the genotyping, significantly association of SSc were found for: dominant model of ApaI and BglI (both OR (95% CI) = 1.80 (1.03,3.16), p = 0.040). Furthermore, the elevation of erythrocyte sedimentation rate (ESR) had a higher percentage of BglI GT genotype frequency (p = 0.034) and dominant model of ApaI (p = 0.016) in SSc. There was high linkage disequilibrium was detected in BglI and ApaI polymorphisms (r² = 1.0, D' = 1.0), Tru9I and rs11168267 (r² = 0.926, D' = 0.969), respectively. No significant difference were found in these four haplotypes (all p >0.05). The correlation between VD levels and VDR gene polymorphisms was not statistically significant.

CONCLUSIONS

Our preliminary study indicates the ApaI and BglI genotype may possibly have a role in the pathogenesis of SSc patients. Dominant model of ApaI and BglI GT genotype frequency may be associated with the increased risk of ESR.

Williams Syndrome, Human Self-Domestication, and Language Evolution

Language evolution resulted from changes in our biology, behavior, and culture. One source of these changes might be human self-domestication. Williams syndrome (WS) is a clinical condition with a clearly defined genetic basis which results in a distinctive behavioral and cognitive profile, including enhanced sociability. In this paper we show evidence that the WS phenotype can be satisfactorily construed as a hyper-domesticated human phenotype, plausibly resulting from the effect of the WS hemideletion on selected candidates for domestication and neural crest (NC) function. Specifically, we show that genes involved in animal domestication and NC development and function are significantly dysregulated in the blood of subjects with WS. We also discuss the consequences of this link between domestication and WS for our current understanding of language evolution.

Effects of genetic variants on serum parathyroid hormone in hyperparathyroidism and end-stage renal disease patients: A systematic review and meta-analysis

BACKGROUND

Parathyroid hormone (PTH) is one of the principal regulators of calcium homeostasis, crucial for normal functioning of the kidneys, bones, heart, and nervous system. Different pathologic conditions can affect serum PTH level resulting in hyperparathyroidism or hypoparathyroidism. Our study assessed the association of previously reported polymorphisms with the level of PTH (expressed in pg/mL) among individuals with different pathologic conditions affecting PTH level.

METHODS

We searched Web of Science, MEDLINE, and Scopus to identify relevant articles published up to July 2017. The search yielded 6967 publications of which 44 fulfilled the inclusion criteria. We conducted meta-analyses for calcium-sensing receptor gene (CaSR) rs1801725 polymorphism in patients with primary hyperparathyroidism and vitamin D receptor gene (VDR) rs1544410 polymorphism in patients with end-stage renal disease (ESRD).

RESULTS

None of the polymorphisms were significantly associated with PTH levels in the overall population. In subgroup analysis by ethnicity for VDR rs1544410 gene polymorphism, we found significant differences under dominant model (SMD: -0.18 [-0.32, -0.05], P < .01) and AA versus GG comparison (SMD: -0.29 [-0.52, -0.06], P < .01) in Asian patients with ESRD, while nominally significant results (P < .05) were observed for AG versus GG and AA versus GG comparisons in European individuals with ESRD.

CONCLUSION

Scientific evidence of genetic association of serum PTH level among individuals with different pathologic conditions remains deficient and published results provide weak evidence. Further well-conducted studies on larger sample sets designed according to evidence-based principles are warranted to assure clinically applicable findings.

Vitamin D Receptor TaqI Polymorphism Is Associated With Reduced Follicle Number in Women Utilizing Assisted Reproductive Technologies

PURPOSE

Calcitriol, or 1,25-hydroxycholecalciferol, is the active form of vitamin D. It binds and activates vitamin D receptor (VDR). Infertility and defective folliculogenesis have been observed in female vdr-knockout mice; however, whether VDR polymorphisms affect human ovarian responses to controlled ovarian stimulation (COS) remains unclear. We hypothesized that VDR polymorphisms are associated with infertility and COS responses. Thus, we evaluated the association between the TaqI, BsmI, and FokI VDR polymorphisms and ovarian responses in women undergoing COS.

METHODS

In this study, we recruited a control group (n = 121) comprising volunteers with a history of natural conception and a second group of women undergoing COS (n = 70). TaqI, BsmI, and FokI genotyping was performed via restriction fragment length polymorphism analysis or TaqMan qPCR and Sanger sequencing. Intrafollicular 25(OH)D contents were measured in follicular fluid collected from COS patients during oocyte retrieval. Ovarian response parameters were obtained from patient medical records.

RESULTS

There were no significant differences in the genotype frequencies of VDR polymorphisms (TaqI, BsmI and FokI) between the control and COS groups. However, the allele frequency of TaqI (C allele) was significantly lower in the COS group than in the control group (p = 0.02). Follicle number but not oocyte number was lower in patients with TaqI polymorphic (TC/CC) genotypes (p = 0.03). Importantly, the ratio between the number of follicles retrieved and intrafollicular estradiol concentrations was higher in patients with the TC/CC TaqI genotypes (p < 0.02).

CONCLUSION

We identified an association between the VDR TaqI polymorphism and reduced follicle number in women undergoing COS, suggesting that VDR signaling affects the ovarian response to stimulation via unknown mechanisms.

Association of vitamin D receptor gene polymorphisms with diabetic dyslipidemia in the elderly male population in North China

Background

The prevalence of dyslipidemia is rising alarmingly in elderly Han Chinese male patients with type 2 diabetes mellitus (T2DM). The genetic factors that contribute to the development of diabetic dyslipidemia remain incompletely identified. This study was conducted to assess the association between vitamin D receptor (VDR) polymorphisms and development of dyslipidemia in the Han elderly male population with T2DM in North China.

Methods

A total of 242 T2DM patients with dyslipidemia (DH group, n=108) or without dyslipidemia (DO group, n=134) and 100 controls were genotyped for ApaI, TaqI and FokI single nucleotide polymorphisms (SNPs) of the VDR gene using polymerase chain reaction-restriction fragment length polymorphism and sequencing. The frequency and distribution of the SNPs were compared between cases and controls.

Results

The distribution of genotypes of VDR-FokI was significantly different between the control and DM group (P=0.033), as well as between the control and DH subgroup (P=0.011) but not DO subgroup (P=0.111). The frequency of C allele and CC genotype of FokI was significantly higher in the DH patients than in the controls (P=0.015 and P=0.003, respectively). Logistic regression analysis in a dominant model homozygous for the C allele of the FokI SNP showed that CC genotype was associated with DH patients (OR =1.797, 95% CI: 1.077–2.999, P=0.025). Significant associations of the ApaI and TaqI SNPs with either DO or DH subjects were not observed.

Conclusion

These findings suggest that CC genotype of VDR-FokI is a risk factor for T2DM patients with dyslipidemia in elderly males in North China.

VDR Gene variation and insulin resistance related diseases

Background

Vitamin D status may influence the risk of Insulin resistance related diseases such as Type 2 diabetes (T2DM), metabolic syndrome (MetS), and polycystic ovarian syndrome (PCOS). Several studies have assessed vitamin D receptor (VDR) gene polymorphism in relationship with these diseases; however, results remain inconsistent. Our study was conducted to elucidate whether VDR Gene polymorphisms could predict insulin resistance on a large scale.

Methods

A meta-analysis using MEDLINE and EMBASE, was performed up to December 16th, 2016. Studies reporting association of vitamin D gene polymorphism with incident T2DM, MetS and PCOS outcomes were included and sub-group analysis by pigment of skin and latitude were performed.

Results

A total of 28 articles based on four gene variation, and comprising 9232 participants with 5193 Insulin resistance related diseases patients were included. No significant associations of the VDR ApaI, BsmI, FokI and TaqI variant with Insulin resistance related diseases were found. However, sub-group analysis analysis showed that PCOS in TaqI (OR = 1.47, 95% CI = 1.03–2.09, P = 0.03) for T allele and MetS for G allele (OR = 1.41, 95% CI = 1.07–1.85, P = 0.01) in BsmI was significant association with VDR gene polymorphism. Simultaneously, sub-group analysis showed VDR ApaI rs7975232(G > T)variant was associated with insulin resistance related diseases in Asians (GG/GT + TT) (OR, 1.62; 95% CI, 1.03–2.53; P = 0.04) and population who lived in middle latitude district (30–60°) (GG/GT + TT) (OR, 1.22; 95% CI, 1.04–1.43; P = 0.02), VDR BsmI rs1544410 (A > G)and VDR Taq1rs731236 (T/C) variant were associated with insulin resistance related diseases in Caucasian (dark-pigmented).

Conclusion

The results suggested that the association between insulin resistance related diseases and VDR ApaI, BsmI, FokI variant was more obvious in dark-pigmented Caucasians and Asians but not in Caucasian with white skin.

Study and evaluation the impact of vitamin D receptor variants on the risk of type 2 diabetes mellitus in Han Chinese

BACKGROUND

Vitamin D and the vitamin D receptor (VDR) are associated with susceptibility to type 2 diabetes mellitus (T2DM). The purpose of the present study was to screen more single nucleotide polymorphisms (SNPs) of VDR and assess their effects on the risk of T2DM in Han Chinese.

METHOD

Four SNPs were genotyped in 1191 individuals (397 cases, 794 controls). Allele frequencies and genotype distributions were analyzed. Effects were investigated by evaluating genotype distribution with regard to phenotypes, insulin resistance, and β-cell function. Haplotype analysis and gene risk score (GRS) were used to evaluate the combined and additive roles of VDR SNPs on T2DM pathogenesis.

RESULTS

There was a significant association between rs739837 and T2DM in two models and allele frequency distribution. The novel locus rs2239179 differed significantly between cases and controls, especially in males and those aged >55 years, in three models and allele frequency distribution. The TT genotype of rs739837 was associated with higher triglyceride than GG and TG genotypes, and higher total cholesterol levels than the GG genotype. Compared with the GTGA haplotype, the GCGG haplotype reduced the risk of T2DM. Trend Chi-squared tests showed that there was significant association between the weighted GRS and the risk of T2DM (P_trend  = 0.034).

CONCLUSION

This study provides novel evidence that rs739837 is associated with lipid metabolism in T2DM patients. The rs739837 and rs2239179 SNPs were associated with the risk of T2DM in Han Chinese. The VDR SNPs had combined and additive effects on the risk of T2DM.

MANAGEMENT OF ENDOCRINE DISEASE: The effect of vitamin D supplementation on glycaemic control in patients with type 2 diabetes mellitus: a systematic review and meta-analysis

OBJECTIVE

Epidemiologic studies suggest that vitamin D status plays a role in glycaemic control in patients with type 2 diabetes. However, intervention studies yielded inconsistent results. The aim of this study is to systematically review the effect of vitamin D supplementation on glycaemic control in patients with type 2 diabetes.

METHODS

Systematic review and meta-analysis. We searched Medline, Embase and the Cochrane Library for RCTs examining the effect of vitamin D supplementation on glycaemic control in patients with type 2 diabetes. A random-effects model meta-analysis was performed to obtain a summarized outcome of vitamin D supplementation on HbA_1c, fasting glucose and homeostasis model assessment - insulin resistance (HOMA-IR).

RESULTS

Twenty-three RCTs were included in this systematic review representing a total of 1797 patients with type 2 diabetes. Mean (± s.d.) change in serum 25-hydroxyvitamin D varied from 1.8 ± 10.2 nmol/L to 80.1 ± 54.0 nmol/L. Nineteen studies included HbA_1c as outcome variable. Combining these studies no significant effect in change of HbA_1c was seen after vitamin D intervention compared with placebo. A significant effect of vitamin D supplementation was seen on fasting glucose in a subgroup of studies (n = 4) with a mean baseline HbA_1c ≥ 8% (64 mmol/mol) (standardized difference in means: 0.36; 95% CI: 0.12-0.61, P = 0.003).

CONCLUSIONS

Current evidence of RCTs does not support short-term vitamin D supplementation in a heterogeneous population with type 2 diabetes. However, in patients with poorly controlled diabetes, a favourable effect of vitamin D is seen on fasting glucose.

The association between vitamin D receptor gene polymorphisms (TaqI and FokI), Type 2 diabetes, and micro-/macrovascular complications in postmenopausal women

Introduction

Since there is evidence of the action of vitamin D as a modulator of insulin release and atherosclerosis, it may well be that the vitamin D receptor polymorphisms are associated with diabetes and its chronic complications.

Aims

To examine the associations between vitamin D receptor polymorphisms (FokI and TaqI) and Type 2 diabetes (T2DM) and its associated chronic complications in postmenopausal women.

Methods

This cross-sectional study analyzed 100 postmenopausal women with T2DM (mean age 65.7±7.18 years) and 100 postmenopausal women without diabetes in the control group (mean age 65.1±9.18 years; P=0.1608). We evaluated clinical and metabolic parameters and analyzed TaqI and FokI polymorphisms.

Results

There were no significant differences in genotype and allele frequencies between patients and controls in either of the polymorphisms studied. In the group of patients with diabetes, there were no significant differences in either polymorphism in relation to stroke, retinopathy, nephropathy, or neuropathy. However, in patients with T2DM and coronary artery disease, f genotype (P=0.0361) and the combination of Ff + ff genotypes were observed less frequently (P=0.0462).

Conclusion

This study suggests the potential protective factor of FokI polymorphism for coronary artery disease in postmenopausal women with T2DM in the recessive model.