Interplay between 3'-UTR polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and the risk of ischemic stroke

The Association Between Thymidylate Synthase Gene Polymorphisms and the Risk of Ischemic Stroke in Chinese Han Population

Family history of hypertension, smoking, diabetes and alcohol consumption and atherosclerotic plaque were identified as common risk factors in IS. We aimed at investigating the relationship between Thymidylate Synthase (TS) gene polymorphisms and ischemic stroke (IS).This case-control research selected and genotyped three single nucleotide polymorphisms (SNPs)of TS( rs699517, rs2790, and rs151264360) with Sanger sequencing in Chinese Han population. We also adopted logistic regression analysis in genetic models for calculating odds ratios and 95% confidence intervals. Genotype-Tissue Expression(GTEx) database analyzed the tissue-specific expression and TS polymorphisms. The ischemic stroke patients showed higher low-density lipoprotein cholesterol and total homocysteine (tHcy). It was found that patients with the TT genotype of rs699517 and GG genotype of rs2790 had larger degrees of tHcy than those with CC + CT genotypes and AA + AG genotypes, respectively. The genotype distribution of the three SNPs did not deviate from Hardy-Weinberg equilibrium (HWE). Haplotype analysis showed that T-G-del was the major haplotype in IS, and C-A-ins was the major haplotype in controls. GTEx database indicated that the rs699517 and rs2790 increased the expression of TS in healthy human and associated with TS expression level in a single tissue. In conclusion: This study has shown that TS rs699517 and rs2790 were significantly related to ischemic stroke patients.

Detection of Methylene Tetrahydrofolate Reductase (MTHFR C677T) Mutation among Acute Lymphoblastic Leukemia in Sudanese Patients

Background

A genetic polymorphism that causes abnormal folate metabolism may lead to genomic instability and increase susceptibility to malignancies such as Acute Lymphoblastic leukemia (ALL). The purpose of this research is to identify methylene tetrahydrofolate reductase (MTHFR C677T) (NCBI ID: 4524) mutation in ALL patients.

Methods

The study was a descriptive case-control hospital-based study with one hundred Sudanese participants divided equally into fifty (50) Sudanese ALL diagnosed patients as cases and fifty (50) Sudanese individuals as controls. The MTHFR C677T mutant allele was detected using conventional PCR, with the primer sequence of MTHFR C677T F-TGAAGGAAGGTGTCTGCGGGA R-AGGACGGTGCGGTGAGAGTG. The study was conducted from January to March 2023, and samples were collected from the Radiation and Isotops Center at Khartoum Hospital.

Results

The investigation revealed that 12 of the 50 patients in the case group (24%) had the MTHFR C677T mutant allele, and the study also revealed that there is significant correlation with the control group. There is no significant relationship between socio-demographic variables and MTHFR mutation detection in ALL patients. Also, the sociodemographic variables predictors of MTHFR mutation among ALL patients adjusted for smoking habit revealed no significant relationship.

Conclusion

According to the findings of this study, the mutant allele of the Methylene Tetra Hydro Folate Reductase C677T was detected and demonstrated varying degrees of significance. It was concluded that the MTHFR C677T gene mutation was associated with acute lymphoblastic leukemia in Sudanese patients.

Relationship between MTHFR C677T, homocysteine, and ischemic stroke in a large sample of the Han Chinese population

Ischemic stroke, one of the prevalent causes of death and disability worldwide, is linked to environmental and genetic factors, including polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene involved in homocysteine metabolism. The present study aimed to explore the relationship between the MTHFR C677T variant, plasma homocysteine, and risk of developing large-artery atherosclerotic ischemic stroke (LAAIS) among Han Chinese. A population-based case-control study, which included 1810 patients with LAAIS and 1765 unrelated control subjects, was conducted. Compared to the controls, LAAIS patients had a significantly higher prevalence of hypertension, diabetes mellitus, smoking, and alcohol consumption (P < .001), as well as significantly higher mean fasting blood glucose, triglyceride, total cholesterol, and plasma homocysteine levels (P < .001). The TT homozygous genotype correlated with increased risk of developing LAAIS, as indicated by a significantly higher odds ratio (OR) compared to the CT and CC genotypes, in both additive (OR = 3.215, P = .01) and recessive models (OR = 3.265, P = .01). The plasma homocysteine level was genotype-dependent according to the following trend: TT > CT > CC. In conclusion, our data demonstrate that, in spite of its low prevalence in both patients and controls (1.5% vs 0.8%), the MTHFR C677T variant could, at least in part, affect homocysteine levels and this, either alone or in combination with other factors, increases the risk of LAAIS.

Pre-microRNAs single nucleotide variants (rs3746444 A > G and rs2910164 C > G) increase the risk of ischemic stroke in the Egyptian population: a case–control study

Background

Ischemic stroke (IS) is the most leading cause of morbidity and mortality worldwide. Micro RNA (miRNA) genetic variants have been identified as a part of IS non-modifiable risk markers. This study aims to identify the possible association of rs2910164 C > G of pre-miRNA-146a and rs3746444 A > G of pre-miRNA-499 with increased IS risk. C-reactive protein (CRP) was studied as one of the mediators of the genetic disturbance in IS. The study included 100 patients with atherosclerotic IS and 100 age and sex matched healthy controls with more than one risk factor for IS. Variants were evaluated by the real-time polymerase chain reaction technique using TaqMan probes. CRP levels were assayed by immunoturbidimetry method on COBAS analyzer.

Results

Regarding rs3746444 A > G, the G allele, and its containing genotypes (GG and GG + AG) were associated with high IS incidence. Increased CRP levels were found to induce IS by GG and GG + AG genotypes, with a cut value of 7.5 mg/ L in differentiation between AA genotype and GG + AG genotypes. Combining the G allele of rs3746444 A > G with either G or C allele of rs2910164 C > G had enhanced the risk. For rs2910164 C > G, the G allele, and the combined GG + GC genotypes were associated with IS risk elevation with no correlation to CRP levels.

Conclusion

The G involving genetic variants of rs3746444 A > G and rs2910164 C > G were associated with an enhanced IS risk. CRP showed higher levels in GG and AG genotypes of rs3746444 with no relation to rs2910164 genotypes.

MTHFR Gene Polymorphisms and Cardiovascular Risk Factors, Clinical-Imagistic Features and Outcome in Cerebral Venous Sinus Thrombosis

Cerebral venous sinus thrombosis (CVST) as a severe neurological emergency, is represented by variable conditions in its clinic presentation, onset, risk factors, neuroimagistic features and outcome. The genetic polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C was associated with CVST. We aimed to characterize the prevalence of MTHFR gene polymorphisms associated with cardiovascular risk factors in the group of patients with CVST. Also, we studied additional causes associated with CVST including local infections, general infections, obstetric causes (pregnancy, puerperium) and head injury. This is a retrospective study including 114 patients which referred to our hospital between February 2012-February 2020. The protocol included demographic (age, sex), clinical, neuroimagistic features, paraclinic (genetic polymorphism of MTHFR, factor V G1691A-Leiden, prothrombin G20210A, PAI-1 675 4G/5G; Homocysteine level, the lipid profile, blood glucose and Glycohemoglobin HbA1c, high- sensitive C- reactive protein- hsCRP) data, as well as treatment and outcome. The mean age was 37.55 years with a female predominance (65.79%). In the first group of patients with inherited thrombophilia (60 cases; 52.63%) we found genetic mutation includes MTHFR C677T (38.59%) and A1298C (14.03%), factor V G1691A- Leiden (15.78%), prothrombin G20210A (2.63%), PAI-1 675 4G/5G (42.98%), and hyperhomocysteinemia (35.08%). At the second group with other etiology of CVST, except thrombophilia, we included 54 patients (47.36%). The most common sites of thrombosis were the superior sagittal sinus (52.63%). Headache was the most common symptom (91.22%) and seizures were the main clinical presentation (54.38%). The MTHFR polymorphism was significantly correlated with higher total cholesterol (TC) (p = 0.023), low- density lipoprotein cholesterol (LDL) (p = 0.008), homocysteine level (tHcy) (p < 0.001). Inside the first group with MTHFR polymorphism we have found a significant difference between the levels of homocysteine at the patients with MTHFR C677T versus MTHFR A1298C polymorphism (p < 0.001). The high-sensitive C-reactive protein (hsCRP) was increased in both groups of patients, but the level was much higher in the second group (p = 0.046). Mortality rate was of 2.63%. Demographic, clinical and neuroimagistic presentation of CVST in our study was similar with other studies on the matter, with a high frequency of thrombophilia causes. MTHFR gene polymorphisms (C677T and A1298C) are increased in prevalence in CVST. PAI-1 675 4G/5G gene mutation seems to be involved in CVST etiology. Plasma C-reactive protein level and hyperhomocysteinemia should be considered as a prognostic factor in CVST.

Interaction Between Methylenetetrahydrofolate Reductase (MTHFR) Gene Polymorphisms and Environment with Susceptibility to Ischemic Stroke in Chinese Population

Aims:

To investigate the association of several single-nucleotide polymorphisms (SNPs) within methylenetetrahydrofolate reductase (MTHFR) gene, and additional gene–environment interaction with ischemic stroke (IS) risk.

Methods:

Testing for Hardy–Weinberg equilibrium in controls was conducted using SNPstats (online software: http://bioinfo.iconcologia.net/SNPstats). Generalized multifactor dimensionality reduction (GMDR) was used to screen the best interaction combination among four SNPs within MTHFR gene and smoking or alcohol drinking.

Results:

The frequency of the rs4846049-A allele was 28.6% in IS patients and 19.1% in normal controls, in addition, the frequency of the rs3737967-T allele was 27.9% in IS patients and 20.3% in normal controls, which was also indicating a statistically significant difference. The rs4846049-A and rs3737967-T were associated with an increased risk of IS risk; adjusted odds ratios (ORs) (95% confidence interval [CI]) were 1.76 (1.28–2.13) and 1.51 (1.13–1.97), respectively. GMDR model found significant gene–alcohol drinking interaction combination, but no significant gene–tobacco smoking interaction combinations. In order to obtain the odds ratios and 95% CI for the joint effects of gene–alcohol drinking on IS, we conducted stratified analysis for interaction effect using logistic regression. We found that alcohol drinkers with rs4846049-CA/AA genotype also have the highest IS risk, compared with never drinkers with rs4846049-CC genotype, OR (95% CI) = 3.12 (1.83–4.45), after adjustment for age, smoke, and smoking status.

Conclusions:

The rs4846049-A and rs3737967-T, gene–environment interaction between rs1764391 and rs918592, gene–environment interaction between rs4846049 and alcohol drinking were all associated with increased IS risk.

The Role of Transient Receptor Potential Channels in Blood-Brain Barrier Dysfunction after Ischemic Stroke

Stroke is the leading cause of long-term disability, demanding an ever-increasing need to find treatment. Transient receptor potential (TRP) channels are nonselective Ca²⁺-permeable channels, among which TRPC, TRPM, and TRPV are widely expressed in the brain. Dysfunction of the blood brain barrier (BBB) is a core feature of stroke and is associated with severity of injury. As studies have shown, TRP channels influence various neuronal functions by regulating the BBB. Here, we briefly review the role of TRP channel in the BBB dysfunction after stroke, and explore the therapeutic potential of TRP-targeted therapy.

MTHFR Gene Polymorphisms Prevalence and Cardiovascular Risk Factors Involved in Cardioembolic Stroke Type and Severity

Background: Cardioembolic stroke (CES), generally known as the most severe subtype of ischemic stroke, is related to many factors, including diabetes mellitus (DM), hypertension (HTN), smoking, hyperlipidemia and atrial fibrillation (AF). Genetic mutations of the methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C have been recently associated with ischemic stroke. The purpose of this study was to analyze the prevalence of MTHFR gene polymorphisms correlated with cardiovascular risk factors in a selected population of patients with CES due to non-valvular AF (NVAF). Methods: This cross-sectional study was performed on 67 consecutive patients with acute cardioembolic stroke admitted to our hospital. The protocol included general physical examination, neurological clinical status and stroke severity evaluation, imagistic evaluation and genetic testing of MTHFRC677T and A1298C polymorphisms. Results: The prevalence of MTHFR polymorphisms in the study population was 38.2% for C677T and 40.3% for A1298C. The C677T mutation was significantly correlated with increased diastolic blood pressure (DBP) values (p = 0.007), higher total cholesterol (TC) (p = 0.003), low-density lipoprotein cholesterol (LDLc) (p = 0.003) and triglycerides (TGL) (p = 0.001), increased high-sensitive C-reactive protein (hsCRP) values (p = 0.015), HbA1c (p = 0.004) and left ventricle ejection fraction (LVEF) (p = 0.047) and lower high-density lipoprotein cholesterol (HDLc) (p < 0.001) compared to patients without this genetic variant. This genetic profile also included significantly higher CHA₂DS₂VASC (p = 0.029) and HASBLED (Hypertension, Abnormal liver/renal function, Stroke, Bleeding, Labile INR, Elderly age(>65 years), Drug/Alcohol usage history/Medication usage with bleeding predisposition) (p = 0.025) scores. Stroke severity in patients with MTHFRA1298C mutation was significantly increased when applying National Institutes of Health Stroke Scale (NIHSS) (p = 0.006) and modified Rankin scale (mRS) (p = 0.020) scores. The presence of A1298C mutation as a dependent variable was associated with significantly higher TGL values (odds ratio (OR) = 2.983, 95%CI = (1.972, 7.994)). Conclusions: The results obtained in this study demonstrate that MTHFR gene polymorphisms have a high prevalence in an NVAF cardioembolic stroke population. Moreover, an association between C677T mutation and stroke severity was highlighted. The C677T mutation in patients with NVAF was correlated with a higher incidence of cardiovascular comorbidities (hypertension HTN, heart failure (HF), dyslipidemia, type II diabetes mellitus (T2DM) with high HbA1c and increased inflammatory state). The A1298CMTHFR gene mutation was associated with a higher incidence of previous lacunar stroke and stroke recurrence rate, while dyslipidemia was the main cardiovascular comorbidity in this category.

3'-UTR Polymorphisms of Vitamin B-Related Genes Are Associated with Osteoporosis and Osteoporotic Vertebral Compression Fractures (OVCFs) in Postmenopausal Women

As life expectancy increases, the prevalence of osteoporosis is increasing. In addition to vitamin D which is well established to have an association with osteoporosis, B vitamins, such as thiamine, folate (vitamin B9), and cobalamin (vitamin B12), could affect bone metabolism, bone quality, and fracture risk in humans by influencing homocysteine/folate metabolism. Despite the crucial role of B vitamins in bone metabolism, there are few studies regarding associations between B vitamin-related genes and osteoporosis. In this study, we investigated the genetic association of four single nucleotide polymorphisms (SNPs) within the 3’-untranslated regions of vitamin B-related genes, including TCN2 (encodes transcobalamin II), CD320 (encodes transcobalamin II receptor), SLC19A1 (encodes reduced folate carrier protein 1), and SLC19A2 (encodes thiamine carrier 1), with osteoporosis and osteoporotic vertebral compression fracture (OVCF). We recruited 301 postmenopausal women and performed genotyping of CD320 rs9426C>T,TCN2 rs10418C>T, SLC19A1 rs1051296G>T, and SLC19A2 rs16862199C>T using a polymerization chain reaction-restriction fragment length polymorphism assay. There was a significantly higher incidence of both osteoporosis (AOR 5.019; 95% CI, 1.533–16.430, p < 0.05) and OVCF (AOR, 5.760; 95% CI, 1.480–22.417, p < 0.05) in individuals with genotype CD320 CT+TT and high homocysteine concentrations. Allele combination analysis revealed that two combinations, namely CD320 C-TCN2 T-SLC19A1 T-SLC19A2 C (OR, 3.244; 95% CI, 1.478–7.120, p < 0.05) and CD320 T-TCN2 C-SLC19A1 G-SLC19A2 C (OR, 2.287; 95% CI, 1.094–4.782, p < 0.05), were significantly more frequent among the osteoporosis group. Our findings suggest that SNPs within the CD320 gene in 3´-UTR may contribute to osteoporosis and OVCF occurrences in some individuals. Furthermore, specific allele combinations of CD320, TCN2, SLC19A1, and SLC19A2 may contribute to increased susceptibility to osteoporosis and OVCF.

Genetic Risk Factors of Intracranial Atherosclerosis

PURPOSE OF REVIEW

Intracranial atherosclerosis (ICAS) is the most common cause of stroke throughout the world. It also increases the risk of recurrent stroke and dementia. As a complex and multifactorial disease, ICAS is influenced by multiple genetic, biological, and environmental factors. This review summarizes the candidate gene and genome-wide studies aimed at discovering genetic risk factors of ICAS.

RECENT FINDINGS

Numerous studies have focused on the association between single-nucleotide polymorphisms (SNPs) of atherosclerosis-related genes and the risk of ICAS. Variants in adiponectin Q (ADIPOQ), ring finger protein 213 (RNF213), apolipoprotein E (APOE), phosphodiesterase 4D (PDE4D), methylenetetrahydrofolate reductase (MTHFR), lipoprotein lipase (LPL), α-adducin (ADD1) genes, angiotensin-converting enzyme (ACE), and other genes related to renin-angiotensin-aldosterone system have been associated with ICAS. We review the available evidences on the candidate genes and SNPs associated with genetic susceptibility to ICAS, and point out future developments of this field. Genetic discoveries could have clinical implications for intracranial atherosclerotic disease.

Rs4846049 Polymorphism at the 3'-UTR of MTHFR Gene: Association with Susceptibility to Childhood Acute Lymphoblastic Leukemia

Background

Accumulating evidence has suggested the polymorphisms of methylenetetrahydrofolate reductase (MTHFR) were associated with susceptibility to childhood acute lymphoblastic leukemia (ALL). However, the known conclusions of currently known polymorphic loci (677 C > T and 1298 A > C) remain controversial. This study was to investigate new genetic biomarkers for ALL by analyzing the MTHFR polymorphisms at the 3′-untranslated region, which is a location bound by miRNAs.

Methods

Polymorphisms of rs4846049 (miR-555 binding) were assessed by PCR amplification and direct sequencing in 110 ALL patients and 105 healthy controls. The relative expression of MTHFR was detected by qRT-PCR.

Results

Overall, genotype distribution or allele carrier frequencies were not significantly different between patients with ALL and healthy controls (P > 0.05). Subgroup analysis results showed that T allele (OR = 0.134, 95% CI = 0.028–0.639; P=0.005) or genotypes with T allele (TT + GT) (OR = 0.133, 95% CI: 0.024–0.727; P=0.017) may be a protective factor for ALL susceptibility in patients with age >8 years. This conclusion was also true for the group only focusing on the precursor B-cell ALL patients. Furthermore, karyotype abnormality was more commonly observed in patients with the GG genotype (56.0%) compared to carriers of TT (0%) or GT (40.6%) genotypes, while c-myc break frequency was significantly higher in TT carriers (33%) than that of patients with GT (3.1%) or GG (0%) genotypes. PCR analysis showed patients carrying the GG genotype of rs4846049 exhibited the reduced mRNA expression of MTHFR.

Conclusion

MTHFR rs4846049 polymorphism may be associated with increased risk of childhood with ALL and MTHFR mRNA expression.

Common Variations in Prothrombotic Genes and Susceptibility to Ischemic Stroke in Young Patients: A Case-Control Study in Southeast Iran

Background and Objective: Evidence indicates that genetic factors may be involved in the risk of ischemic stroke (IS). The aim of this study was to assess the effect of genetic polymorphisms located in exons or untranslated regions of MTHFR as well as FV genes on ischemic stroke. Materials and Methods: In this case-control study, 106 patients with IS and 157 healthy volunteers (age <50 years) were genotyped for MTHFR C677T, A1298C, C2572A and C4869G, FVL, and prothrombin G20210A polymorphisms. Results: The MTHFR 677CT genotype was more frequent in patients and increased risk of IS with Odds Ratio = 1.9. The MTHFR A1298C and C2572A polymorphisms were not associated with IS in dominant and recessive models. Our findings showed a significant decrease in the MTHFR4869CG genotype in IS patients, and this variant was associated with a decreased risk of IS in the dominant model. The CAAT haplotype was associated with increased risk, and the GAAC haplotype was associated with decreased risk of IS compared to other haplotypes. There was no relation between FVL G1691A polymorphism and IS risk. Conclusions: The present study showed that the MTHFR 677CT genotype was more frequent and the MTHFR 4869CG genotype was less frequent in young IS patients.

Combined Biomarkers Composed of Environment and Genetic Factors in Stroke

It was widely accepted that stroke onset was the result of interactions between environment and genetic factors. However, the combined biomarkers covering environment and genetic factors and their interplay information in stroke were still lacking. In this study, we proposed a framework to identify the targeting or indicating role each factor played in the combined stroke biomarkers. A combined set of 36 biomarkers were identified based on evaluation and importance scores. Validations on three independent microarray data sets justified that the obtained markers were pervasively effective in discriminating stroke patients of different stages from healthy people on genetic levels. 8 and 3 genetic factors were identified as biomarkers in the acute and recovery phases of stroke, respectively. For example, the expression changing of SERPINH1 only appeared in the acute phase of stroke showing its targeting role in the combined biomarker. Compared with this, 11 genetic factors such as MMP9 were found to be differentially expressed in both acute and recovery phases of stroke showing their indicating roles in stroke. Functional analyses further revealed that the biomarkers could be grouped into 4 closely related processes of stroke including prevention, occurrence, processing, and recovery, respectively. These results indicated that the adoption of interactions between environment and genetic factors would be helpful in selecting robust and biologically relevant biomarkers, which cast a new insight for stroke biomarker identification.