Triangular relationship between CYP2R1 gene polymorphism, serum 25(OH)D3 levels and T2DM in a Chinese rural population

Gene-environment interaction in myopia

Myopia is a health issue that has attracted global attention due to its high prevalence and vision-threatening complications. It is well known that the onset and progression of myopia are related to both genetic and environmental factors: more than 450 common genetic loci have been found to be associated with myopia, while near work and outdoor time are the main environmental risk factors. As for many complex traits, gene-environment interactions are implicated in myopia development. To date, several genetic loci have been found to interact with near work or educational level. Gene-environment interaction research on myopia could yield models that provide more accurate risk predictions, thus improving targeted treatments and preventive strategies. Additionally, such investigations might have the potential to reveal novel genetic information. In this review, we summarised the findings in this field and proposed some topics for future investigations.

Association of CYP2R1 and VDR Polymorphisms with Metabolic Syndrome Components in Non-Diabetic Brazilian Adolescents

Associations between vitamin D deficiency and metabolic syndrome (MS) have been reported; however, the underlying biological mechanisms remain controversial. The aim of this study was to investigate the associations of CYP2R1 and VDR variants with MS and MS components in non-diabetic Brazilian adolescents. This cross-sectional study included 174 adolescents who were classified as overweight/obese. Three CYP2R1 variants and four VDR variants were identified by allelic discrimination. The CYP2R1 polymorphisms, rs12794714 (GG genotype) (odds ratio [OR] = 3.54, 95% confidence interval [CI] = 1.24–10.14, p = 0.023) and rs10741657 (recessive model—GG genotype) (OR = 3.90, 95%CI = 1.18–12.92, p = 0.026) were significantly associated with an increased risk of MS and hyperglycemia, respectively. The AG + GG genotype (dominant model) of the rs2060793 CYP2R1 polymorphism was associated with hyperglycemia protection (OR = 0.28, 95%CI = 0.08–0.92, p = 0.037). Furthermore, the CC genotype (recessive model) of the rs7975232 VDR polymorphism was significantly associated with a risk of hypertension (OR = 5.91, 95%CI = 1.91–18.32, p = 0.002). In conclusion, the CYP2R1 rs12794714 polymorphism could be considered a possible new molecular marker for predicting the risk of MS; CYP2R1 rs10741657 polymorphism and VDR rs7975232 polymorphism are associated with an increased risk of diabetes and hypertension in adolescents with overweight/obesity.

Undergraduate laboratory series that employs a complete polymerase chain reaction-restriction fragment length polymorphism experiment for determination of a single nucleotide polymorphism in CYP2R1 gene

Nowadays, novel Biochemistry lab techniques are being introduced at a very fast pace in scientific research. This requires development of new labs for undergraduate Biochemistry courses to equip the students with up-to-date techniques. However, the time limit of Biochemistry labs for undergraduate students represents a major obstacle. This article presents a clear set of laboratory exercises designed to introduce students to the use of polymerase chain reaction-restriction-fragment length polymorphism (PCR-RFLP) as a means of detection of genetic variants. Three consecutive lab experiments have been designed for the undergraduate students to serve this purpose. The first session was performed in a computer lab (dry lab) where students were taught how to obtain a specific gene sequence, identify an exact single nucleotide polymorphism location, choose the target sequence for amplification, design specific primers for this particular sequence and choose the most suitable restriction enzyme from web tools. The second and third lab sessions were performed as wet labs where in the second lab session, students optimized PCR conditions and performed a successful PCR. The PCR products were kept for use in the third lab session where they utilized the selected restriction enzyme and carried out gel electrophoresis to determine the exact genotype.

The influence of CYP2R1 polymorphisms and gene-obesity interaction with hypertension risk in a Chinese rural population

BACKGROUND AND AIMS

Several studies have reported that variants in CYP2R1 have been linked with an increased risk of hypertension. However, the interaction between CYP2R1 variants and environmental factors on the susceptibility of hypertension remained unclear. Therefore, this study evaluated the influence of CYP2R1 polymorphisms on hypertension susceptibility, and explored the interaction effect of CYP2R1 variations and obesity on the disease.

METHODS AND RESULTS

We included 766 incident hypertension cases matched with non-hypertension controls in a 1:1 ratio by sex, age (within 3 years). Two loci in CYP2R1 gene (rs10766197 and rs12794714) were genotyped by TaqMan probe assays. The concentration of 25-hydroxyvitamin-D was determined by human enzyme-linked immunosorbent assay (ELISA) kits. The associations of CYP2R1 polymorphisms and risks of vitamin D deficiency (VDD) were analyzed by logistic regression. Multifactor dimensionality reduction (MDR) was used to analyze the gene-environment interaction. Multiple logistic regression was used to examine the effect of CYP2R1 gene variations, and the interaction between CYP2R1 variation and obesity on hypertension susceptibility. The results showed that rs10766197 (GG vs. AA) and rs12794714 (GG vs. AA) polymorphisms were both associated with an increased risk of VDD (OR = 1.49, 95% confidence interval (CI) = 1.08-2.05 and OR = 1.63, 95% CI = 1.19-2.25, respectively), after adjustment for potential risk factors. We also found that rs12794714 polymorphism was significantly associated with elevated risk of hypertension under the dominant model (OR = 1.26, 95% CI = 1.01-1.56). In addition, the interactions between rs12794714 with both general obesity (OR = 3.93, 95% CI = 2.72-5.68) and central obesity (OR = 3.22, 95% CI = 2.29-4.52) have significant effects on hypertension susceptibility.

CONCLUSIONS

The study provided further evidence that CYP2R1 variation was associated with a higher risk of hypertension in Chinese rural population. The interaction between CYP2R1 rs12794714 and obesity may increase the risk of hypertension.

Vitamin D levels and Vitamin D-related gene polymorphisms in Chinese children with type 1 diabetes

Low vitamin D levels may play a role in type 1 diabetes (T1D) susceptibility. Since 25(OH)D synthesis is genetically regulated, single nucleotide polymorphisms (SNPs) of important genes have also been shown to modulate the risk of T1D, so this study aimed to investigate the relationship between five SNPs in CYP2R1, DHCR7, CYP24A1, VDR genes, serum 25(OH)D levels and T1D in Chinese children. This case-control study included 141 T1D patients and 200 age-matched healthy children.25 (OH) D concentration was determined, genotyping was performed by High resolution melting (HRM). There was a significant difference in the prevalence of vitamin D deficiency, insufficiency, and sufficiency between T1D and healthy controls. (χ ² = 10.86, p = 0.004), however no evidence of the association between any group of SNPs and circulating 25(OH) D levels was observed. The allele distribution of CYP2R1(rs1993116) was significantly different between T1D and control group (p = 0.040), and the C allele carriers of rs1993116 had a higher risk of T1D than the T allele carriers, Carriers of the CC and CT genotypes of rs1993116 have higher T1D risk than those carrying the TT genotype. GMDR analysis revealed a significant interaction between CYP2R1(rs12794714) and CYP2R1(rs1993116) in the risk of T1D with a maximum testing balance accuracy of 60.39%.

Association between Polymorphisms in Vitamin D Pathway-Related Genes, Vitamin D Status, Muscle Mass and Function: A Systematic Review

An association between vitamin D level and muscle-related traits has been frequently reported. Vitamin D level is dependent on various factors such as sunlight exposure and nutrition. But also on genetic factors. We, therefore, hypothesize that single nucleotide polymorphisms (SNPs) within the vitamin D pathway-related genes could contribute to muscle mass and function via an impact on vitamin D level. However, the integration of studies investigating these issues is still missing. Therefore, this review aimed to systematically identify and summarize the available evidence on the association between SNPs within vitamin D pathway-related genes and vitamin D status as well as various muscle traits in healthy adults. The review has been registered on PROSPERO and was conducted following PRISMA guidelines. In total, 77 studies investigating 497 SNPs in 13 different genes were included, with significant associations being reported for 59 different SNPs. Variations in GC, CYP2R1, VDR, and CYP24A1 genes were reported most frequently, whereby especially SNPs in the GC (rs2282679, rs4588, rs1155563, rs7041) and CYP2R1 genes (rs10741657, rs10766197, rs2060793) were confirmed to be associated with vitamin D level in more than 50% of the respective studies. Various muscle traits have been investigated only in relation to four different vitamin D receptor (VDR) polymorphisms (rs7975232, rs2228570, rs1544410, and rs731236). Interestingly, all of them showed only very low confirmation rates (6-17% of the studies). In conclusion, this systematic review presents one of the most comprehensive updates of the association of SNPs in vitamin D pathway-related genes with vitamin D status and muscle traits in healthy adults. It might be used for selecting candidate SNPs for further studies, but also for personalized strategies in identifying individuals at risk for vitamin D deficiency and eventually for determining a potential response to vitamin D supplementation.

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.

Evaluation of the Associations of GC and CYP2R1 Genes and Gene-Obesity Interactions with Type 2 Diabetes Risk in a Chinese Rural Population

INTRODUCTION

Group-specific component (GC) and cytochrome P450 family 2 subfamily R member 1 (CYP2R1) gene polymorphisms and obesity have been associated with an increased risk for development of type 2 diabetes mellitus (T2DM) in Asian populations.

OBJECTIVE

This study assessed the associations of interactions between GC gene variants and CYP2R1 gene variants and between genes and obesity with T2DM risk.

METHODS

A study that included 2,271 subjects was performed. Eight single nucleotide polymorphisms in the GC and CYP2R1 genes were genotyped. Interaction analysis was performed using rs7041 in the GC gene and rs1993116 in the CYP2R1 gene. The effects of multiplicative and additive gene-gene and gene-environment interactions on T2DM risk were assessed.

RESULTS

The T2DM risk was significantly associated with being overweight/obese, abdominal obesity, rs7041, and rs1993116. A significant additive interaction between rs1993116 and rs7041 was associated with T2DM. In addition, there was a significant multiplicative interaction between rs7041 and body mass index (BMI) associated with elevated blood glucose levels, and at a higher BMI (>28.47), the G allele carrier showed a stronger effect than the TT genotype.

CONCLUSIONS

The interactions between GC rs7041-CYP2R1 rs1993116 and GC rs7041-BMI may explain the mechanisms by which these factors increase the risk of T2DM development.

Association between variants in vitamin D-binding protein gene and vitamin D deficiency among pregnant women in china

Background

The prevalence of vitamin D deficiency and insufficiency is extremely high in pregnant women worldwide. However, the association between single nucleotide polymorphisms (SNPs) in vitamin D metabolic pathway genes and 25‐hydroxyvitamin D (25(OH)D) concentration among Chinese pregnant women is seldom reported. The risk of adverse neonatal outcomes due to maternal vitamin D deficiency has not been well investigated.

Methods

A total of 815 pregnant women and 407 infants were enrolled in this study. Serum 25(OH)D concentration was detected. DNA was extracted from the maternal blood for genotyping genetic SNPs in vitamin D pathway. An XGBoost model was established based on SNPs combined with external variables.

Results

Mean serum 25(OH)D level was 15.67 ± 7.98 ng/mL among the pregnant women. Seventy‐five percent of pregnant women had 25(OH)D deficiency in China. SNPs of GC (rs17467825, rs4588, rs2282679, rs2298850, and rs1155563) were significantly associated with maternal 25(OH)D concentration. The influence of variants of rs17467825, rs4588, rs2282679, and rs2298850 on maternal 25(OH)D might be modified by vitamin D supplementation and sunshine exposure. An XGBoost model was established for monitoring 25(OH)D status in pregnant women and provided clinical advice to reduce the risk of 25(OH)D deficiency. Mothers with 25(OH)D deficiency hinted a risk for macrosomia.

Conclusion

A high prevalence of vitamin D deficiency in China has been confirmed. A clinical model was established to guide pregnant women to supplement vitamin D according to genotype. Furthermore, we suggest the effect of maternal vitamin D status on the risk of macrosomia.

Low serum 25-hydroxyvitamin D levels may increase the detrimental effect of VDR variants on the risk of essential hypertension

BACKGROUND/OBJECTIVES

The present cross-sectional study evaluated the association of vitamin D receptor (VDR) variants with serum 25(OH)D₃ levels and their interaction on essential hypertension (EH) risk.

SUBJECTS/METHODS

1539 patients were eligible in the study population. Two loci in VDR gene (rs2239179, rs2189480) were genotyped by TaqMan probe assays. Logistic regression, Kruskal-Wallis rank test and Chi-square test were used to determine the association among VDR polymorphisms, serum vitamin D metabolites, and the risk of EH. Interaction plots were performed to explain the interaction effects of circulating 25(OH)D₃ levels and VDR variants on EH susceptibility.

RESULTS

After potential confounding adjustment, we observed that the mutations of VDR (rs2239179/rs2189480) were associated with the increased risk of EH (P < 0.05). Moreover, plasma 25(OH)D₃ levels were inversely associated with EH, However, we did not find the association between serum 25(OH)D₃ and VDR variants. When comparing with wild-type homozygous and heterozygous genotype carriers with vitamin D sufficiency, hypovitaminosis D and insufficient participants carrying homozygous variant genotype of rs2239179 showed a higher risk of EH, increased by 113% (OR = 2.13, 95% CI: 1.20, 3.80); Notably, the detrimental effect of rs2239179 homozygous variant on EH became stronger in the case of serum 25(OH)D₃ <30 ng/ml. However, we did not find the interaction effect between rs2189480 variants and serum 25(OH)D₃ levels on the risk of EH.

CONCLUSIONS

Our results suggested that the mutations of VDR may accelerate the progression of EH etiology, especially when suffering hypovitaminnosis D and insufficiency.