MTHFR C677T gene mutation as a risk factor for arterial stroke: a hospital based study

Case report: Clinical profile, molecular genetics, and neuroimaging findings presenting in a patient with Kearns-Sayre syndrome associated with inherited thrombophilia

Background

Kearns-Sayre syndrome (KSS) is classified as one of the mitochondrial DNA (mtDNA) deletion syndromes with multisystemic involvement. Additionally, the negative prognosis is associated with inherited thrombophilia, which includes the presence of homozygous Factor V G1691A Leiden mutation, MTHFR gene polymorphisms C677T and A1298C, and PAI-1 675 homozygous genotype 5G/5G.

Case presentation

This case report presents a 48-year-old man with chronic progressive external ophthalmoplegia, bilateral ptosis, cerebellar ataxia, cardiovascular signs (syncope, dilated cardiomyopathy, and cardiac arrest) with electrocardiographic abnormalities (first-degree atrioventricular block and major right bundle branch block), endocrine dysfunction (short stature, growth hormone insufficiency, primary gonadal insufficiency, hypothyroidism, and secondary hyperparathyroidism), molecular genetic tests (MT-TL2 gene), and abnormal MRI brain images, thus leading to the diagnosis of KSS. The patient came back 4 weeks after the diagnosis to the emergency department with massive bilateral pulmonary embolism with syncope at onset, acute cardiorespiratory failure, deep left femoral-popliteal vein thrombophlebitis, and altered neurological status. In the intensive care unit, he received mechanical ventilation through intubation. Significant improvement was seen after 2 weeks. The patient tested positive for inherited thrombophilia and was discharged in stable conditions on a new treatment with Rivaroxaban 20 mg/day. At 6 months of follow-up, ECG-Holter monitoring and MRI brain images remained unchanged. However, after 3 months, the patient died suddenly while sleeping at home.

Conclusion

The genetic tests performed on KSS patients should also include those for inherited thrombophilia. By detecting these mutations, we can prevent major complications such as cerebral venous sinus thrombosis, coronary accidents, or sudden death.

Stroke in Young Military Men With Heterozygous for MTHFR Gene Mutation or Factor V Leiden Gene Mutation Associated With Patent Foramen Ovale: Report of Two Cases and Therapeutic Strategy

We report two cases of Brazilian patients (a 22-year-old male and a 48-year-old male) with ischemic stroke, whose arterial vascular study and echocardiographic investigation did not reveal any steno-occlusive arterial disease or typical cardioembolic finding, such as atrial fibrillation or myocardial dysfunction. A transcranial Doppler ultrasound and a transesophageal echocardiogram showed a patent foramen ovale (PFO), and the laboratory screening for coagulation abnormalities showed heterozygosity for MTHFR C677T and A1298C in one of the patients and heterozygosity for factor V Leiden gene mutations in the other patient. The significance of the association of PFO with Methylenetetrahydrofolate (MTHFR) C677T and A1298C variants or factor V Leiden mutation is discussed as a possible cause of ischemic stroke through paradoxical embolism from a venous source. There is a high prevalence of these two mentioned conditions in the general population, so we discuss two cases in which indication for anticoagulant therapy or percutaneous closure of PFO prevails.

Association of methylenetetrahydrofolate reductase (MTHFR) rs1801133 (677C>T) gene polymorphism with ischemic stroke risk in different populations: An updated meta-analysis

Background: Recently, increasing evidence has implicated methylenetetrahydrofolate reductase (MTHFR) gene mutation as a risk factor for ischemic stroke (IS) in the general population. However, studies have been inconclusive and lack evidence on specific populations. We aim to determine whether the rs1801133 (NC_000001.11 (MTHFR):g. 677C>T (p.Ala222Val) variant, we termed as MTHFR rs1801133 (677 C>T), is linked to an increased risk of IS in different age groups and ancestry groups. Methods: The literature relevant to our study was found by searching the PubMed, Cochrane Library, Web of Science, EMBASE, and CNKI databases. A random effect model analysis was used to calculate the pooled odds ratio (OR) and 95% confidence interval (CI) to evaluate any possible association. We conducted a subgroup analysis based on the age and ancestry groups of the included populations. Results: As of March 2022, 1,925 citations had been identified in electronic databases, of which 96 studies involving 34,814 subjects met our eligibility criteria. A strong link was found between IS and the MTHFR gene rs1801133 (677C>T) polymorphism in all genetic models [dominant genetic model (OR = 1.47; 95%CI = 1.33-1.61; p < 0.001), recessive genetic model (OR = 1.52; 95%CI = 1.36-1.71; p < 0.001), heterozygous model (OR = 1.36; 95%CI = 1.24-1.48; p < 0.001), homozygous model (OR = 1.82; 95%CI = 1.58-2.11; p < 0.001), and T allelic genetic model (OR = 1.37; 95%CI = 1.27-1.48; p < 0.001)]. Further subgroup analyses indicated that the MTHFR rs1801133 (677C>T) variant may increase the risk of IS in Asian, Hispanic, or Latin population, middle-aged, and elderly populations (p < 0.001). Conclusion: Our results implied that mutation of the T allele of MTHFR rs1801133 (677C>T) could be a risk factor for IS. A significant association was found among Asian, Hispanic, or Latin population, middle-aged, and elderly people.

Relationship of Methylenetetrahydrofolate Reductase (MTHFR) C677T Variation With Susceptibility of Patients With Ischemic Stroke: A Meta-Analysis

Discovery and validation of genetic factors for multifactorial and polygenic disorders like stroke are needed to make progress in precision medicine. Although some traditional risk factors for stroke have been identified, they do not fully explain the pathophysiological mechanism of ischemic stroke. The research of genetic risk factors is becoming increasingly relevant in the understanding of stroke mechanisms and the finding of population-specific therapeutic targets. The methylenetetrahydrofolate reductase (MTHFR) gene is involved in homocysteine metabolism, and a high homocysteine level is a risk factor for stroke. Using a meta-analysis technique, we investigated the link between the MTHFR C677T gene polymorphism and the risk of ischemic stroke.

We used the electronic databases PubMed, Medline, Embase, and Google Scholar to find articles in the Journal of Stroke. If heterogeneity was more than 50%, pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a random-effects model; otherwise, a fixed-effects model was used.

A total of 67 case-control studies with 17,704 cases and 21,981 controls met our inclusion criteria. The Asian population was represented by 41 studies, whereas the Caucasian population was represented by 26. Under the recessive model, a gene polymorphism at the 677 location of the MTHFR gene is related to an elevated risk of ischemic stroke (OR: 1.29, 95% CI: 1.22-1.37, P < 0.001).

People who have the MTHFR C677T gene polymorphism have a greater risk of stroke than people who do not.

Association of MTHFR Polymorphisms with H-Type Hypertension: A Systemic Review and Network Meta-Analysis of Diagnostic Test Accuracy

Purpose

An association between MTHFR polymorphisms and H-type hypertension (H-HTN) has been investigated by epidemiological studies, but results have been inconsistent. Thus, a systematic assessment of the association was performed based on a literature review and pooled analysis, to provide stronger evidence on the effects of single nucleotide polymorphisms on H-HTN risk.

Methods

Three investigators independently retrieved relevant studies in PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), Wanfang Database, and China Biomedical Literature Database (CBM). A fixed or random effects model was selected to calculate pooled odds ratio (OR) and 95% confidence intervals (CIs). A network meta-analysis of diagnostic test and Thakkinstian's algorithm were used to select the most appropriate genetic model, along with false-positive report probability (FPRP) for noteworthy associations. All data were processed using Stata 15.0 and Meta-Disc.

Results

A total of 14 studies involving 1759 cases and 1581 controls for MTHFR were included in our meta-analysis. In a direct meta-analysis, we found that MTHFR C667T rs1801133 significantly increased the risk of H-HTN susceptibility except for an overdominant model. However, MTHFR A1298C rs1801131 polymorphism had no significant correlation with H-HTN risk. Besides, MTHFR C667T rs1801133 is a potential diagnostic biomarker for estimating H-HTN risk. The results indicated that the dominant model was an optimal diagnosis model for excluding diseases, which could reduce a missed diagnosis rate and further improve the accuracy of disease diagnosis.

Conclusion

The present result suggests that MTHFR C667T rs1801133 polymorphism is associated with H-HTN risk and may act as a promising predictive biomarker for H-HTN risk. However, further well-designed studies are warranted to confirm these results.

Spinal cord infarction in a young adult: What is the culprit?

Context: Non-traumatic spinal cord infarction in the young adult is usually associated with a single or multiple genetic mutations. There are certain gene mutations that are more commonly associated with spinal cord infarctions. Homozygous or heterozygous mutations, and single mutations or polymorphism, do not seem to determine the probability of spinal cord infarction.Findings: We add another case of spinal cord infarction in a young adult to the few reported in the literature, and discuss the value of genetic studies and genetic counseling.Conclusion: Non-traumatic spinal cord infarction is usually caused by a genetic mutation. Early recognition of this entity and definition of the mutation will limit unnecessary and invasive procedures and allows early rehabilitation, preventive measures for complications and genetic counseling.

The role of B vitamins in stroke prevention

Elevated plasma levels of homocysteine (Hcy) are a recognized risk factor for stroke. This relationship represents one aspect of the debated `Hcy hypothesis'. Elevated Hcy may be an independent and treatable cause of atherosclerosis and thrombotic vascular diseases. Further observations indicate that proper dietary supplementation with B-vitamins decreases total plasma Hcy concentrations and may be an effective intervention for stroke prevention. Metabolic vitamin B₁₂ deficiency is a nutritional determinant of total Hcy and stroke risk. Genetic factors may link B vitamins with stroke severity due to the impact on Hcy metabolism of polymorphism in the genes coding for methylenetetrahydrofolate reductase, methionine-synthase, methionine synthase reductase, and cystathionine β-synthase. Several meta-analyses of large randomized controlled trials exist. However, they are not completely in agreement about B vitamins' role, particularly folic acid levels, vitamin B₁₂, and B₆, in lowering the homocysteine concentrations in people at high stroke risk. A very complex relationship exists between Hcy and B vitamins, and several factors appear to modify the preventive effects of B vitamins in stroke. This review highlights the regulating factors of the active role of B vitamins active in stroke prevention. Also, inputs for further large, well-designed studies, for specific, particularly sensitive subgroups are given.

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.

Clinical characteristics of H-type hypertension and its relationship with the MTHFR C677T polymorphism in a Zhuang population from Guangxi, China

Objective

This study was designed to assess the clinical presentation of patients with H‐type hypertension who were of Zhuang nationality in Guangxi, China. The relationship between the C677T polymorphism in the MTHFR gene and H‐type hypertension was also assessed.

Methods

This was a case‐control study in which 185 Zhuang nationality patients with hypertension that had been hospitalized at the Wuming Hospital of Guangxi Medical University between February 2018 and December 2018 were assessed for plasma homocysteine (Hcy) levels. These levels were used to divide patients into H‐type (>15 μmol/L) and non‐H‐type (≤15 μmol/L) hypertension groups. Patient clinical data were then analyzed, and PCR was used to analyze samples from all patients for the presence of the C677T polymorphism in the MTHFR gene. Differences between these two groups of hypertension patients were then compared using appropriate statistical methods.

Results

We found that relative to patients in the non‐H‐type hypertension group, patients in the H‐type hypertension group exhibited significant differences in sex, age, urea nitrogen levels, creatinine levels, and uric acid levels. There were, however, no significant differences between these two groups with respect to interventricular septum thickness, left ventricular posterior wall thickness, or ejection fraction. We did not detect any association between the MTHFR gene C677T polymorphism and H‐type hypertension in Zhuang nationality individuals in Guangxi.

Conclusion

Risk of H‐type hypertension is not associated with the MTHFR C677T polymorphism in hypertensive individuals of Guangxi Zhuang nationality in China.

The association of MTHFR C677T variant with increased risk of ischemic stroke in the elderly population: a meta-analysis of observational studies

Background

C677T point mutation in methylenetetrahydrofolate reductase (MTHFR) gene have been found to be associated with ischemic stroke in general population, while the results seem inconsistent. We aim to assess the association between variant MTHFR C677T variant and increased risk of ischemic stroke and focus on the elderly population.

Methods

We searched PubMed, Embase, Cochrane Library, and Web of Science for eligible studies. Odds ratios (ORs) were calculated with the two-tailed 95% confidence intervals (CIs) by using a random effects model to evaluate any possible association. Among the Chinese and non-Chinese populations, we conducted a subgroup analysis.

Results

The electronic database search yielded 1,358 citations as of December 2017; finally, nine case-control studies involving 3,337 subjects fulfilled our eligibility criteria for inclusion in the study. The pooled results showed that MTHFR C677T variant increased the risk of ischemic stroke (OR = 1.23, 95%CI 1.06–1.43, P = 0.0067 for CT + TT vs. CC; OR = 1.18, 95%CI 1.01–1.38, P = 0.0333 for CT vs. CC; OR = 1.41, 95%CI 1.14–1.75, P = 0.0016 for TT vs. CC; OR = 1.27, 95%CI 1.05–1.54, P = 0.0145 for TT vs. CC + CT; OR = 1.18, 95%CI 1.06–1.31, P = 0.0023 for T-allele vs. C-allele). Further subgroup analyses in the Chinese population indicated that MTHFR C677T variant was associated with a higher risk of ischemic stroke.

Conclusion

Our findings showed that T-allele increases risk for stroke in the pooled sample. This association was statistically significant in the Chinese cohorts and showed a similar trend in the non-Chinese cohorts. (Word count: 237).

Dna Methylation in Esophageal Diseases Including Cancer: Special Reference to hMLH1 Gene Promoter Status

Aims and Background

Chronic inflammation leading to malignancy in the esophagus may be due to errors in mismatch repair (MMR) genes such as hMLH1. Promoter hypermethylation has been suggested as the main cause of hMLH1 silencing. In this study we assessed hMLH1 promoter hypermethylation in a range of esophageal diseases. Further, we evaluated the role of factors affecting the methylation cycle: (1) methyt-enetetrahydrofolate reductase (MTHFR) C677T mutation and (2) serum homocysteine levels.

Methods

We endoscopically and histologically categorized 124 paired tissue and blood samples from patients into cancer, precancer, reflux esophagitis, other inflammatory esophagitis and controls (endoscopically normal). Restriction enzyme-based methylation analysis was carried out to assess hMLH1 promoter hypermethylation.

Results and Conclusions

hMLH1 promoter hypermethylation in tissue was seen in 63.5% of patients with cancer and 53.8% of those with precancer, which was significantly increased when compared with controls (P <0.001). There appears to be an increasing degree of hMLH1 hypermethylation with disease progression. Patients with gastroesophageal reflux disease (GERD) showed a high degree of hMLH1 hypermethylation (88.8%), indicating that local environment due to reflux may be promoting hypermethylation. We suggest that GERD is a progressive condition with an increased risk for developing into cancer. Only 14.5% of cases exhibited hypermethylation both in tissue and blood. Hence, we conclude that hMLH1 promoter hypermethylation is a tissue-specific change in the esophagus and blood testing cannot be used as a noninvasive tool to assess it. DNA methylation is dependent on the methylation cycle; MTHFR is a major enzyme in this pathway. MTHFR mutations did not correlate with hypermethylation or clinical pathology (P >0.5). Elevated homocysteine levels, independent of MTHFR mutation, correlated significantly with hMLH1 hypermethylation in tissue (P <0.005). Our study shows that hMLH1 hypermethylation in tissue may be the primary event caused by endogenous/exogenous factors in esophageal diseases, aiding disease progression.

Risks associated with the stroke predisposition at young age: facts and hypotheses in light of individualized predictive and preventive approach

Stroke is one of the most devastating pathologies of the early twenty-first century demonstrating 1-month case-fatality rates ranging from 13 to 35% worldwide. Though the majority of cases do occur in individuals at an advanced age, a persistently increasing portion of the patient cohorts is affected early in life. Current studies provide alarming statistics for the incidence of "young" strokes including adolescents. Young stroke is a multifactorial disease involving genetic predisposition but also a number of modifiable factors, the synergic combination of which potentiates the risks. The article analyzes the prevalence and impacts of "traditional" risk factors such as sedentary lifestyle, smoking, abnormal alcohol consumption, drug abuse, overweight, hypertension, abnormal sleep patterns, and usage of hormonal contraceptives, among others. Further, less explored risks such as primary vascular dysregulation and associated symptoms characteristic for Flammer syndrome (FS) are considered, and the relevance of the FS phenotype for the stroke predisposition at young age is hypothesized. Considering the high prevalence of known genetic and modifiable risk factors in the overall predisposition to the young stroke, the risk mitigating measures are recommended including innovative screening programs by application of specialized questionnaires and biomarker panels as well as educational programs adapted to the target audiences such as children, adolescents, and young adults.

Genetic polymorphisms of methylenetetrahydrofolate reductase C677T and risk of ischemic stroke in a southern Chinese Hakka population

Previous studies have shown that methylenetetrahydrofolate reductase (MTHFR) gene to be a genetic risk factor for the susceptibility to ischemic stroke. The aim of this case-control study was to investigate whether the polymorphisms of MTHFR C677T were associated with the susceptibility to ischemic stroke in a southern Chinese Hakka population. In this study, a total of 1967 ischemic stroke patients and 2565 controls of Chinese Hakka ethnicity were recruited. The MTHFR C677T polymorphisms were genotyped by polymerase chain reaction (PCR) amplification and microarray method. The risk of ischemic stroke was estimated by logistic regression analysis. The frequencies of CC, CT, and TT genotypes were 52.67% versus 55.63%, 40.31% versus 38.52%, and 7.02% versus 5.85% in patients with ischemic stroke versus controls, respectively. The frequency of T allele was significantly higher in ischemic stroke patients (27.17%) than in controls (25.11%) (P = .026, odds ratio [OR] 1.113, 95% confidence interval [CI] 1.013-1.223). The homozygous TT genotype in the ischemic stroke patients was associated with increased risk (P = .049, OR 1.132, 95% CI 1.001-1.281) when compared with the controls after adjustment for age and sex. The positive association was only found in dominant model without adjustment for age and sex (P = .047, OR 1.127, 95% CI 1.002-1.268). Also, the carrier status of the MTHFR T allele was identified as an independent risk factor for the development ischemic stroke even after the adjustment for conventional risk factors (P = 0.047, OR 1.109, 95% CI 0.964-1.225). Our results provide evidence that variants of MTHFR C677T gene may influence the risk of developing ischemic stroke in a southern Chinese Hakka population. Further studies are needed to confirm this association, which will promote the development of strategies for prevention and treatment of ischemic stroke in our study population.

Genetics of platelet traits in ischaemic stroke: focus on mean platelet volume and platelet count

Purpose/Aim of the study: The aim of this review is to summarize the role of genetic variants affecting mean platelet volume (MPV) and platelet count (PLT) leading to higher platelet reactivity and in turn to thrombotic events like stroke and cardiovascular diseases.

MATERIALS AND METHODS

A search was conducted in PUBMED, MEDLINE, EMBASE, PROQUEST, Science Direct, Cochrane Library, and Google Scholar related to the studies focussing on genome-wide association studies (GWAS), whole exome sequencing (WES), whole genome sequencing (WGS), phenome-wide association studies (PheWAS) and multi-omic analysis that have been employed to identify the genetic variants influencing MPV and PLT.

RESULTS

Antiplatelet agents underscore the crucial role of platelets in the pathogenesis of stroke. Higher platelet reactivity in terms of mean platelet volume (MPV) and platelet count (PLT) contributes significantly to the interindividual variation in platelet reaction at the site of vessel wall injury. Some individuals encounter thrombotic events as platelets get occluded at the site of vessel wall injury whereas others heal the injury without occluding the circulation. Evidence suggests that MPV and PLT have a strong genetic component. High throughput techniques including genome-wide association studies (GWAS), whole exome sequencing (WES), whole genome sequencing (WGS), phenome-wide association studies (PheWAS) and multi-omic analysis have identified different genetic variants influencing MPV and PLT.

CONCLUSIONS

Identification of complex genetic cross talks affecting PLT and MPV might help to develop novel treatment strategies in treating neurovascular diseases like stroke.

Methylenetetrahydrofolate reductase C677T variant and hyperhomocysteinemia in subarachnoid hemorrhage patients from India

Methylenetetrahydrofolate reductase (MTHFR) polymorphism (C677T, A1298C) has been implicated in increased plasma homocysteine (Hcy) levels. The present study was designed to investigate the association between MTHFR polymorphism and increased Hcy levels in subarachnoid haemorrhage (SAH) patients. A total of 150 subjects from North India were included in the study, comprising of 100 SAH patients and 50 healthy controls. Plasma Hcy levels was determined and MTHFR polymorphism (C677T, A1298C) was screened by High resolution melting (HRM) analysis. Plasma Hcy levels were found to be significantly higher (p < 0.001) in SAH patients than in healthy controls. No significant difference in the genotype and allele frequency of MTHFR A1298C was observed. However, frequency of MTHFR C677T genotype, CT (53% vs. 20%; p < 0.001) and TT (15% vs. 2%; p < 0.05) was significantly higher in SAH group as compared to healthy controls. The frequency of T allele (41.5% vs. 12%; p < 0.001) was also found to be higher in SAH patients in comparison to healthy controls. Furthermore, Hcy levels were higher in SAH patients with TT genotype than in patients having CT genotype, whereas CC genotype had lower Hcy levels. The study suggests that higher frequency of MTHFR C677T allele may contribute to etiopathology of SAH through increase in Hcy levels.

Epigenetic regulation of inflammation in stroke

Despite extensive research, treatments for clinical stroke are still limited only to the administration of tissue plasminogen activator and the recent introduction of mechanical thrombectomy, which can be used in only a limited proportion of patients due to time constraints. A plethora of inflammatory events occur during stroke, arising in part due to the body's immune response to brain injury. Neuroinflammation contributes significantly to neuronal cell death and the development of functional impairment and death in stroke patients. Therefore, elucidating the molecular and cellular mechanisms underlying inflammatory damage following stroke injury will be essential for the development of useful therapies. Research findings increasingly point to the likelihood that epigenetic mechanisms play a role in the pathophysiology of stroke. Epigenetics involves the differential regulation of gene expression, including those involved in brain inflammation and remodelling after stroke. Hence, it is conceivable that epigenetic mechanisms may contribute to differential interindividual vulnerability and injury responses to cerebral ischaemia. In this review, we summarize recent findings on the emerging role of epigenetics in the regulation of neuroinflammation in stroke. We also discuss potential epigenetic targets that may be assessed for the development of stroke therapies.

Vascular Genetic Variants and Ischemic Stroke Susceptibility in Albanians from the Republic of Macedonia

BACKGROUND

Acute first-ever ischemic stroke (FIS) is a heterogeneous, polygenic disorder. The contribution of vascular genetic variants as inherited causes of ischemic stroke has remained controversial.

AIM

To examine the association of genetic variants in vascular factors with the occurrence of FIS.

MATERIAL AND METHODS

The current research was performed in a group of 39 patients with FIS (study group) and 102 healthy volunteers (control group). We analyzed the prevalence of vascular genetic variants in following genes: factor V, prothrombin, methylenetetrahydrofolate reductase (MTHFR), factor XIII, plasminogen activator 1, endothelial protein C receptor (EPCR), apolipoprotein B, apolipoprotein E, β-fibrinogen, human platelet antigen 1, angiotensin-converting enzyme (ACE), endothelial nitric oxide synthase (eNOS) and lymphotoxin alpha.

RESULTS

It was found that heterozygous LTA 804C>A and FXIII V34L Leu/Leu were significantly more frequent in patients with FIS than in control group (p = 0.036 and p = 0.017, respectively). The frequency of FXIII V34L Val/Val was significantly lower in patients with FIS than in control group (p = 0.020). Other frequencies of vascular gene variants in patients with FIS and in control group were not significantly different.

CONCLUSIONS

This is the first comprehensive study to present data indicating that polymorphism of vascular genes in the prevalence of acute FIS exists in the Albanian population from the Republic of Macedonia. Variations in these genes have been detected in patients with acute FIS, suggesting that their combination might act in a susceptible or protective manner in this Albanian population.

Heterogenous Distribution of MTHFR Gene Variants among Mestizos and Diverse Amerindian Groups from Mexico

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in folate metabolism. Folate deficiency has been related to several conditions, including neural tube defects (NTDs) and cardiovascular diseases. Hence, MTHFR genetic variants have been studied worldwide, particularly the C677T and A1298C. We genotyped the C677T and A1298C MTHFR polymorphisms in Mexican Amerindians (MAs), from the largest sample included in a genetic study (n = 2026, from 62 ethnic groups), and in a geographically-matched Mexican Mestizo population (MEZ, n = 638). The 677T allele was most frequent in Mexican individuals, particularly in MAs. The frequency of this allele in both MAs and MEZs was clearly enriched in the South region of the country, followed by the Central East and South East regions. In contrast, the frequency of the 1298C risk allele in Mexicans was one of the lowest in the world. Both in MAs and MEZs the variants 677T and 1298C displayed opposite allele frequency gradients from southern to northern Mexico. Our findings suggest that in Mestizos the 677T allele was derived from Amerindians while the 1298C allele was a European contribution. Some subgroups showed an allele frequency distribution that highlighted their genetic diversity. Notably, the distribution of the frequency of the 677T allele was consistent with that of the high incidence of NTDs reported in MEZ.

Fifty years of stroke researches in India

Currently, the stroke incidence in India is much higher than Western industrialized countries. Large vessel intracranial atherosclerosis is the commonest cause of ischemic stroke in India. The common risk factors, that is, hypertension, diabetes, smoking, and dyslipidemia are quite prevalent and inadequately controlled; mainly because of poor public awareness and inadequate infrastructure. Only a small number of ischemic stroke cases are able to have the benefit of thrombolytic therapy. Benefits from stem cell therapy in established stroke cases are under evaluation. Presently, prevention of stroke is the best option considering the Indian scenario through control and/or avoiding risk factors of stroke. Interventional studies are an important need for this scenario.

Quantitative assessment of association between rs1801133 polymorphism and susceptibility to stroke

Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme involved in folate metabolism, which is essential for DNA synthesis and methylation. Genetic variations in the MTHFR gene seem to contribute to a decreased activity of MTHFR, ultimately confer increased susceptibility to stroke. To assess the association between this polymorphism and stroke risk, we conducted a comprehensive meta-analysis based on 73 eligible studies. A total of 73 studies, including 10,225 cases and 13,800 controls identified between 1999 and 2012, were selected through researching the PubMed, MEDLINE, EMBASE, Cochrane Library, Web of Science, and Chinese Biomedical Chinese National Knowledge Infrastructure and Literature database databases. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to assess the association. Overall, a significant elevated risk of stroke risk was associated with the rs1801133 polymorphism in all genetic models (homozygote model: OR 1.296, 95% CI 1.109-1.514; dominant model: OR 1.179, 95% CI 1.058-1.315; recessive model: OR 1.209, 95% CI 1.063-1.375; allele comparison model: OR 1.154, 95% CI 1.061-1.256). In the stratified analyses, significantly increased stroke risks were indicated among Asians in all genetic models (homozygote model: OR 1.726, 95% CI 1.314-2.267; dominant model: OR 1.535, 95% CI 1.282-1.838; recessive model: OR 1.452, 95% CI 1.160-1.818; allele comparison model: OR 1.403, 95% CI 1.211-1.626).The present meta-analysis suggests that rs1801133 polymorphism contributes to the risk of stroke, of note, in Asian populations.

Recurrent cerebral venous thrombosis associated with heterozygote methylenetetrahydrofolate reductase C677T mutation and sickle cell trait without homocysteinemia: an autopsy case report and review of literature

Elevated blood homocysteine concentration and certain genetic mutations have been associated with increased risk for developing arterial and venous thrombosis. A common mutation of methylenetetrahydrofolate reductase, MTHFR C677T, has been associated with elevated homocysteine concentration and increased risk for developing thrombosis in homozygote carriers. Heterozygote carriers for this gene mutation, if associated with other major or minor risk factors for thrombophilia, appear to be prone to develop thrombosis. A postmortem genetic testing for common mutations resulting in thrombophilia should be performed in all individuals who die as a result of thrombosis, regardless of predisposing risk factors, to determine the true prevalence of mutations in these individuals, and to assess the true role of a certain mutation, such as heterozygote MTHFR C677T, in the pathogenesis of thrombosis. Postmortem genetic testing for common mutations associated with thrombophilia in selected cases has potentially life-saving importance to surviving family members. We report a case of recurrent cerebral venous thrombosis in a 19 year old male with history of sickle cell trait, obesity, and high normal blood homocysteine, who was heterozygote for MTHFR C677T mutation.

Genome-wide meta-analysis of homocysteine and methionine metabolism identifies five one carbon metabolism loci and a novel association of ALDH1L1 with ischemic stroke

Circulating homocysteine levels (tHcy), a product of the folate one carbon metabolism pathway (FOCM) through the demethylation of methionine, are heritable and are associated with an increased risk of common diseases such as stroke, cardiovascular disease (CVD), cancer and dementia. The FOCM is the sole source of de novo methyl group synthesis, impacting many biological and epigenetic pathways. However, the genetic determinants of elevated tHcy (hyperhomocysteinemia), dysregulation of methionine metabolism and the underlying biological processes remain unclear. We conducted independent genome-wide association studies and a meta-analysis of methionine metabolism, characterized by post-methionine load test tHcy, in 2,710 participants from the Framingham Heart Study (FHS) and 2,100 participants from the Vitamin Intervention for Stroke Prevention (VISP) clinical trial, and then examined the association of the identified loci with incident stroke in FHS. Five genes in the FOCM pathway (GNMT [p = 1.60 × 10(-63)], CBS [p = 3.15 × 10(-26)], CPS1 [p = 9.10 × 10(-13)], ALDH1L1 [p = 7.3 × 10(-13)] and PSPH [p = 1.17 × 10(-16)]) were strongly associated with the difference between pre- and post-methionine load test tHcy levels (ΔPOST). Of these, one variant in the ALDH1L1 locus, rs2364368, was associated with incident ischemic stroke. Promoter analyses reveal genetic and epigenetic differences that may explain a direct effect on GNMT transcription and a downstream affect on methionine metabolism. Additionally, a genetic-score consisting of the five significant loci explains 13% of the variance of ΔPOST in FHS and 6% of the variance in VISP. Association between variants in FOCM genes with ΔPOST suggest novel mechanisms that lead to differences in methionine metabolism, and possibly the epigenome, impacting disease risk. These data emphasize the importance of a concerted effort to understand regulators of one carbon metabolism as potential therapeutic targets.

Detailed analysis of gene polymorphisms associated with ischemic stroke in South Asians

The burden of stroke is disproportionately high in the South Asian subcontinent with South Asian ethnicity conferring a greater risk of ischemic stroke than European ancestry regardless of country inhabited. While genes associated with stroke in European populations have been investigated, they remain largely unknown in South Asians. We conducted a comprehensive meta-analysis of known genetic polymorphisms associated with South Asian ischemic stroke, and compared effect size of the MTHFR C677T-stroke association with effect sizes predicted from homocysteine-stroke association. Electronic databases were searched up to August 2012 for published case control studies investigating genetic polymorphisms associated with ischemic stroke in South Asians. Pooled odds ratios (OR) for each gene-disease association were calculated using a random-effects model. We identified 26 studies (approximately 2529 stroke cases and 2881 controls) interrogating 33 independent genetic polymorphisms in 22 genes. Ten studies described MTHFR C677T (108 with TT genotype and 2018 with CC genotype) -homocysteine relationship and six studies (735 stroke cases and 713 controls) described homocysteine-ischemic stroke relationship. Risk association ORs were calculated for ACE I/D (OR 5.00; 95% CI, 1.17–21.37; p = 0.03), PDE4D SNP 83 (OR 2.20; 95% CI 1.21–3.99; p = 0.01), PDE4D SNP 32 (OR 1.57; 95% CI 1.01–2.45, p = 0.045) and IL10 G1082A (OR 1.44; 95% CI, 1.09–1.91, p = 0.01). Significant association was observed between elevated plasma homocysteine levels and MTHFR/677 TT genotypes in healthy South Asians (Mean difference (ΔX) 5.18 µmol/L; 95% CI 2.03–8.34: p = 0.001). Our results demonstrate that the genetic etiology of ischemic stroke in South Asians is broadly similar to the risk conferred in Europeans, although the dataset is considerably smaller and warrants the same clinical considerations for risk profiling.

No evidence for the role of somatic mutations and promoter hypermethylation of FH gene in the tumorigenesis of nonsyndromic uterine leiomyomas

Fumarate hydratase (FH) gene is reported to have specific involvement in syndromic uterine tumors, but its role in nonsyndromic forms is still unclear. Hence, the present study has aimed to screen the role of promoter methylation status and mutations in exon 2 and 7 regions of FH gene in the genesis of nonsyndromic uterine leiomyomas. Leiomyoma and myometrium tissues were collected from 85 hysterectomized uterine specimens. DNA from each of the biopsy was subjected to PCR, methylation-specific restriction assay, and DNA sequencing. In silico analysis was carried out to identify the impact of sequence variants on the protein structure. Chi-square (χ (2)) test was used to compare the promoter methylation proportions of leiomyoma and myometrium tissues. No sequence variants were observed in exon 2 region, but three novel heterozygous germ line sequence variants, i.e., c.1010A > C, c.1021 G > A, and c.1066 T > C in exon 7 region of the FH gene were detected in 14/85 (16.5 %) of the cases examined. In silico analysis results showed that c.1010A > C and c.1021 G > A mutations damage the structure and function of FH, whereas c.1066 T > C mutation is mostly tolerant or neutral. No significant difference of FH promoter methylation status between the leiomyoma (11.76 %) and myometrium (5.88 %) tissues was observed (P = 0.176). Therefore, it is concluded that somatic mutations in FH do not show pronounced effect in nonsyndromic uterine leiomyomas compared to that of their syndromic counterparts. However, higher frequency of FH mutations in leiomyoma cases raises the need to conduct larger number of prospective case-control and family-based studies to assess them as risk markers to nonsyndromic leiomyomas.

Cyclooxygenase-2-765G>C functional promoter polymorphism and its association with oral squamous cell carcinoma

AIM

Cyclooxygenase-2 is a key enzyme in the conversion of arachidonic acid to prostaglandins, and has critical role in the progression of several malignancies, including oral squamous cell carcinoma.

METHODS

We designed a case-control study to evaluate the susceptibility of the functional -765G>C genetic variation in oral squamous cell carcinoma patients. Polymerase chain reaction-based restriction fragment length polymorphism analysis was used to determine the polymorphism in oral squamous cell carcinoma (n = 150) patients and healthy controls (n = 150).

RESULTS

The genotype frequencies of cyclooxygenase-2 765G>G, 765G>C, and 765C>C were 73.3%, 18.66%, and 8.0% in the cancer patients, and 94.66%, 4% and 1.3% in the controls, respectively. The cyclooxygenase-2 GC and CC genotypes were significantly associated (P = 0.0003 and P = 0.01, respectively) with oral squamous cell carcinoma patients, when compared to the controls. The 765G>C genotypes were statistically significant, with habitual tobacco chewing and alcohol consumption + smoking (P = 0.05).

CONCLUSIONS

This study highlights the genetic variant that might play a role in mediating susceptibility to oral squamous cell carcinoma in this population.

Inherited thrombophilia in childhood arterial stroke: data from Lebanon

Pediatric ischemic stroke still represents a burden, and more than half of the survivors will experience cognitive or motor disabilities. The objective of this study was to investigate the role of thrombophilia in a cohort of children with arterial ischemic stroke. The records of infants and children with clinically and radiologically confirmed stroke were reviewed. Patients with venous or perinatal stroke were not included. Thirty-three patients were diagnosed with arterial ischemic stroke. The male/female ratio was 1.75:1. The median age was 4 years. The most frequent clinical manifestations were hemiparesis (54.5%) and seizures (33.3%). Genetic thrombophilia testing was available on 24 patients. Nine of the 24 patients (37.5%) were heterozygous for factor V Leiden. None of the patients carried the factor II G20210A variant. Ten patients (41.7%) were heterozygous and 3 (12.5%) were homozygous for methylenetetrahydrofolate reductase (MTHFR) C677T variant. Fifteen patients (62.5%) had one or more genetic polymorphism. Factor V Leiden was significantly associated with arterial ischemic stroke (P < 0.001). Stroke recurred in 2 children with multiple risk factors and MTHFR C677T mutation. Factor V Leiden is one of the major genetic risk factors for pediatric arterial ischemic stroke in Lebanon. MTHFR C677T was prevalent among patients with recurrent stroke.

Mitochondrial insertion-deletion polymorphism: role in disease pathology

AIM

Mitochondrial DNA (mtDNA) sequence variations are associated with a number of human diseases. The 9-bp repeat sequence, CCCCCTCTA, in the intergenic region of MTCO2 and MTTK genes of the mtDNA has been extensively used in phylogenic studies. The sequence has been reported to be polymorphic in south-east Asians in isolated cases of mt diseases. This is the first systemic study identifying the role of insertion-deletion polymorphism in human disease.

RESULTS

A total of 241 patients including those with cardiomyopathy, ataxias, and idiopathic neurological disorders along with 100 controls were screened; 2.9% of patients showed a single repeat (deletion) and 4.14% had three repeats (insertion), whereas all the controls had two repeats (normal).

CONCLUSION

This indicates that the 9-bp insertion-deletion repeat polymorphism plays a role in disease pathology, affecting the expression of the downstream genes of mtDNA and altering ATP generation.

Detection of somatic mutations and germline polymorphisms in mitochondrial DNA of uterine fibroids patients

To identify the role of mitochondrial DNA (mtDNA) mutations in uterine fibroids patients, genomic DNA isolated from paired myometrium and fibroid tissues was screened for mutations. The present study represents the first investigation to report that 10.4% of uterine fibroids cases had either mtDNA mutations or polymorphisms or both. Among the 14 mitochondrial sequence variants identified, seven are somatic mutations (A3327C, G3352A, G3376A, G3380A, G3421A, T15312G, and C15493G) and the remaining (G3316A, C3342A, C3442T, T10205A, A10188G, A10229C, and A10301T) are gene polymorphisms. Somatic mutations were both homo- and heteroplasmic in nature. Of the seven somatic mutations located in the MTND1 and MTCYB genes, five (71.42%) are nonsynonymous in nature, whereas four (57.14%) of the polymorphisms located in MTND1 and MTND3 genes are found to be nonsynonymous. Sequence variants such as G3380A, G3421A, T15312G, G3376A, and G3316A have been earlier described in different human pathologies, but the remaining are novel ones. Mitochondrial somatic mutations and polymorphisms may predispose women to an earlier onset of degenerative cellular processes, which impair oxidative phosphorylation capacity and thereby promote tumorigenesis in uterine smooth muscle cells. Detection of mtDNA sequence variations in fibroid patients raises the need for larger case-control studies to screen the whole mitochondrial genome and evaluate as a future diagnostic biomarker in fibroid patients.

Evaluation of MTHFR C677T polymorphism in ischemic and hemorrhagic stroke patients. A case-control study in a Northern Indian population

OBJECTIVE

The present study was aimed to evaluate MTHFR C677T gene polymorphism in patients with ischemic stroke (IS) and intracerebral hemorrhage (ICH) and compare it with controls.

METHODS

207 patient with IS and 215 with CT/MRI proven ICH were included and compared with 188 healthy controls. The stroke risk factors, location of IS, its vascular territory and in ICH the location of hematoma were noted. MTHFR C677T polymorphism was studied by polymerase chain reaction.

RESULTS

Hypertension was present in 65.9% of ICH and 48.8% of IS. Other stroke risk factors were not significantly different. The frequency of the CC genotype in controls was 68.6%. CT in 28.7% and TT in 2.7%, whereas it was 75.3%, 20.5% and 4.2% in ICH and 66.2%, 39.4% and 2.4% respectively in IS. The frequency of these genotypes as well as allele frequency was not different in IS, ICH as compared to controls, however variant allele was more frequent in IS compared to ICH. Homocysteine level was higher in IS patients with variant genotype

INTERPRETATION

MTHFR C677T gene polymorphism was neither associated with hemorrhagic nor ischemic stroke. However raised homocysteine levels were found to be associated with MTHFRC677-TT genotype in IS patients.

Stroke in young in India

Stroke in young has special significance in developing countries. This is so because some etiologies like cardioembolic infections are more common than in developed countries, and the affection of economically productive group adds further to the overall disease burden. The paper discusses the burden of stroke in young and its implications in a developing country like India along with an approach to identifying different causes that are known to occur in this age group.

Stroke in children: inherited and acquired factors and age-related variations in the presentation of 48 paediatric patients

AIM

Stroke is relatively rare in children and the clinical presentation of paediatric stroke is often subtle. Numerous predisposing risk factors are known, and these can be both inherited and acquired. They include cardiac disease, vascular abnormalities, endothelial damage, infectious diseases, collagen tissue diseases, certain inborn errors of metabolism and anticardiolipin antibody, lupus anticoagulant and deficiencies of protein C, protein S, antithrombin or plasminogen. In addition, abnormal activated protein C resistance (or Factor V Leiden), Factor II G20219A variant, and the thermolabile variant of methylenetetrahydrofolate reductase (MTHFR C677T) need to be considered.

METHODS

To explore the prevalence of different predisposing conditions in paediatric stroke patients, we evaluated 48 patients, including subjects with ischaemic and haemorrhagic stroke subtypes.

RESULTS

Only 7 out of 48 (14.5%) had no recognizable risk factors: the majority of paediatric stroke patients had pre-existing risk factors that predisposed to the condition. The major genetic risk factor in our series of patients was homozygosity for the MTHFR C677T mutation (7 out of 48 patients); three more patients were found to be heterozygous for the Factor V Leiden mutation. Acquired predisposing conditions were present in 23 out of 48 patients and included pulmunar stenosis, head trauma, hyperlipidaemia and varicella infection. A total of 17 patients had both genetic and acquired predisposing factors.

CONCLUSION

Our results emphasize that multiple predisposing risk factors commonly predispose to paediatric stroke. In addition, the primary clinical presentation appeared to differ between the older and younger children: hemiparesis was the typical presentation in children <1 year of age while seizure predominated in older children.

Methylenetetrahydrofolate reductase homozygous mutation in a young boy with cerebellar infarction

Posterior circulation vascular occlusive disease in children is a rare and uncommonly reported event. Among the numerous risk factors, the methylenetetrahydrofolate reductase (MTHFR) mutation is considered to be a common genetic cause of thrombosis in adults and children. Recently, a link between the MTHFR mutation and cerebrovascular disorders was reported in children. Diffusion tensor imaging (DTI) is a great improvement on magnetic resonance imaging (MRI), making the in vivo anatomical and pathological study of the brain and its fibers possible. In our patient cerebellar infarction was associated with MTHFR mutation and, in a standard neurological examination, DTI revealed normal white matter tracts.

Tumor necrosis factor alpha -C850T polymorphism is significantly associated with endometriosis in Asian Indian women

OBJECTIVE

To establish the association of tumor necrosis factor alpha (TNFA) promoter C850T polymorphism in Asian Indian women with endometriosis.

DESIGN

Case control study, from multiple gynecological centers from Hyderabad, a cosmopolitan city in southern India. The study included 245 women who comprised 110 surgically confirmed cases of endometriosis, 50 ultrasonographically confirmed cases of fibroid tumors, and 85 healthy female volunteers.

SETTING

Academic hospital.

PATIENT(S)

The cases were 245 women, 160 patients and 85 controls.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Tumor necrosis factor alpha -C850T polymorphism may be used as a molecular marker for endometriosis in our population.

RESULT(S)

In this study we have demonstrated an association between TNFA -C850T polymorphism and endometriosis. The T allele is significantly associated with endometriosis when compared to women with fibroids as well as healthy controls. Our data imply that the T allele is associated with endometriosis (OR = 1.9594: 95% CI, 1.3833-2.7753; in our population. The TT genotype increases the risk of endometriosis by fourfold (4.5542: 95% CI, 2.0388-10.1701.

CONCLUSION(S)

This study suggests that -C850T TNFA gene polymorphism could be used as a relevant molecular marker to identify women with risk of developing endometriosis in our population.

Relationship of homocysteine with other risk factors and outcome of ischemic stroke

OBJECTIVE

Hyperhomocysteinemia (HH) is an emerging risk factor for ischemic stroke but its role in outcome is controversial. We compare the risk factors, nature of stroke and outcome of patients with and without hyperhomocysteinemia.

PATIENTS AND METHODS

CT proven ischemic stroke patients were included. The conventional risk factors such as diabetes, hypertension, hyperlipidemia, obesity, smoking, and family history of stroke were recorded. Dietary history was noted. Fasting serum homocysteine (Hcy), B12 and folic acid were estimated after 1 month of stroke. Severity of stroke was assessed by Canadian Neurological Scale (CNS) and outcome at 3 months by Barthel Index (BI) score into good (BI > or = 12) and poor (BI < 12). Serum Hcy, B12 and folic acid were also estimated in 200 normal healthy volunteers.

RESULTS

There were 198 patients with ischemic stroke whose median age was 56 years and 36 were females. In the study group, 41.4% patients were vegetarian, 55.1% hypertensive, 24.7% diabetic, 30.8% smoker, 61.1% sedentary and 28.8% obese. 23.2% had past history of stroke and 21.7% had stroke in their first degree relative. Serum cholesterol was elevated in 11.7% and LDL in 10.8% patients. Serum Hcy was elevated in 60.6% and serum B12 low in 25.7% and folic acid in 42.1%. Hcy levels correlated with serum B12 and LDL. Patients with hyperhomocysteinemia had significantly better outcome at 3 months. Hcy levels in stroke patients did not significantly differ from controls.

CONCLUSION

Hyperhomocysteinemia is found in 60.6% stroke patients, which is related to low serum B12 level. Patients with hyperhomocysteinemia had a better 3-month outcome.

MTHFR homozygous mutation and additional risk factors for cerebral infarction in a large Italian family

Several cases with cerebral infarctions associated with the C677T mutation in the methylenetetrahydrofolate reductase gene (MTHFR) have been reported. Given the large number of asymptomatic individuals with the MTHFR mutation, additional risk factors for cerebral infarction should be considered. This study describes a large family with the MTHFR mutation and a combination of heterozygous factor V Leiden mutations and different additional exogenous and endogenous thrombogenic risk factors. Psychomotor retardation and a left fronto-insular infarct associated with the MTHFR mutation together with diminished factor VII and low level of protein C was documented in the first patient. In the second patient, generalized epilepsy and a malacic area in the right nucleus lenticularis was associated with the MTHFR mutation and a low level of protein C. In the third patient, right hemiparesis and a left fronto-temporal porencephalic cyst were documented, together with the MTHFR mutation and hyperhomocysteinemia. An extensive search of additional circumstantial and genetic thrombogenic risk factors should be useful for prophylaxis and prognosis of infants with cerebral infarctions associated with the MTHFR mutation and of their related family members.

Relationship of angiotensin-converting enzyme gene polymorphism with nephropathy associated with Type 2 diabetes mellitus in Asian Indians

OBJECTIVE

Diabetic nephropathy (DN) has become the leading cause of end-stage renal disease, but the pathogenesis of this condition is not exactly understood. Several studies from different parts of the world have examined angiotensin-converting enzyme (ACE) gene polymorphism as a candidate for DN. Two studies yielding controversial results have been reported from India. To rule out this discrepancy, we carried out a hospital-based study on a cohort from our population to determine whether ACE gene polymorphism is associated with DN.

RESEARCH DESIGN AND METHODS

ACE gene polymorphism was analyzed by polymerase chain reaction in 460 individuals consisting of 174 cases of DN, 175 cases of Type 2 diabetes mellitus (DM), and 111 controls. The DN cases included in the study were Type 2 DM cases with serum creatinine >1.5 mg/dl and serum albumin >30 mg/dl in a 24-h urine sample.

RESULTS

ACE insertion/deletion genotyping analysis showed DD genotype in 22.75% of DN cases, 15.42% of Type 2 DM cases, and 21.62% of controls. Chi-square test between the DN group and the control group did not show a significant difference in D allele. However, the difference was significant at P<.05 between the DN group and the DM group. The odds ratio was 2.0953 (95% confidence interval=1.35-3.2522), indicating a significant association of DD genotype and D allele with DN.

CONCLUSION

Our data enable us to conclude that Asian Indians with D allele and Type 2 DM are at greater risk for developing DN.

Association of gene polymorphism with genetic susceptibility to stroke in Asian populations: a meta-analysis

Stroke is a heterogeneous multifactorial disease and is thought to have a polygenic basis. Case-control studies on gene sequence variations have identified a number of potential genetic predisposition factors, but due to the conflicting results, uncertainty remains on the effect of these polymorphisms on risk for the development of stroke. To qualitatively and quantitatively assess the risk associated with different gene polymorphisms for stroke in Asian populations, we comprehensively searched and identified all the studies of association. Clinically overt case-control studies were selected only if neuroimaging had been used as the confirmatory measure for diagnosis of stroke. We performed a meta-analysis of the three most investigated genes, viz., methylenetetrahydrofolate reductase (MTHFR), apolipoprotein E (ApoE) and angiotensin-converting enzyme (ACE). Statistically significant association with stroke were identified for C677T polymorphism of MTHFR [random effects odds ratio (OR) = 1.47, 95% confidence interval (95% CI) 1.19, 1.82; P = 0.0004] and marginally significant association was detected with allele epsilon 4 of ApoE (random effects OR = 1.47, 95% CI 1.00, 2.15; P = 0.049). The sensitivity analysis (exclusion of studies with controls not in Hardy-Weinberg equilibrium) revealed a significant association of stroke with the MTHFR C677T and ApoE epsilon 4 alleles but showed no association with ACE gene insertion/deletion polymorphism.

Methylenetetrahydrofolate reductase gene polymorphisms are associated with ischemic and hemorrhagic stroke: Dual effect of MTHFR polymorphisms C677T and A1298C

Hyperhomocysteinemia is an independent risk factor for ischemic stroke. The enzyme methylenetetrahydrofolate reductase (MTHFR) plays a critical role in modulating the levels of plasma homocysteine. Two polymorphisms in the MTHFR gene, C677T, A1298C result in reduced enzyme activity. The mechanisms of ischemic and hemorrhagic stroke are not well understood. Although controversial, previous studies have shown evidence of causality of both stroke subtypes in patients with methylenetetrahydrofolate reductase gene polymorphisms. Therefore, we examined whether the C677T and A1298C polymorphisms of MTHFR gene are genetic risk factors for both ischemic and hemorrhagic stroke in a Turkish Caucasian population. In a case-control study, 120 total unrelated stroke patients (92 ischemic stroke, 28 hemorrhagic stroke), and 259 healthy controls were genotyped for C677T and A1298C polymorphisms of the MTHFR gene using a PCR-RFLP based-method. The MTHFR 1298C allele (chi(2)=8.589; P=0.014), C1298C genotype (OR=2.544; P=0.004), and C677C/C1298C compound genotype (OR=3.020; P=0.001) were associated with overall stroke. The MTHFR 1298C allele (chi(2)=11.166; P=0.004), C1298C genotype (OR=2.950; P=0.001), and C677C/C1298C compound genotype (OR=3.463, P=0.0001) were strongly associated with ischemic stroke. Interestingly however, the MTHFR 677T allele (chi(2)=6.033; P=0.049), T677T genotype (OR=3.120; P=0.014), and T677T/A1298A compound genotype (OR=4.211; P=0.002) were associated with hemorrhagic stroke. In conclusion, the C677T and A1298C polymorphisms of the MTHFR gene are genetic risk factors for hamorrhagic and ischemic stroke respectively, independent of other atherothrombotic risk factors.

A proteomic approach for the characterization of C677T mutation of the human gene methylenetetrahydrofolate reductase

Methylenetetrahydrofolate reductase (MTHFR) catalyzes the conversion of methylenetetrahydrofolate (CH2H4folate) to methyltetrahydrofolate (CH3H4folate). The C677T mutation is a common polymorphism of the human enzyme that leads to the replacement of Ala222Val, thermolability of MTHFR, and mild elevation of plasma homocysteine levels. A mild hyperhomocysteinemia is known to be risk factor for cardiovascular and thrombotic diseases, ischemic stroke, neural tube defects, late on-set dementia, and pregnancy complications. Human plasma of subjects carrying the C677T mutation in the MTHFR gene has been investigated for their protein pattern in order to identify novel molecular hallmarks. 2-D analysis of the plasma protein allowed the identification of a specific pattern associated with the TT mutant genotype. Noteworthy, we found one spot shifted to a more basic pI in mutant individuals, and MS identification corresponded to vitamin D-binding protein (DBP or group component (Gc) globulin). MS/MS peptide sequencing allowed to discriminate different allelic variants in the investigated clinical groups. These data confirmed by molecular genetic analysis highlight the novel association between the C677T MTHFR genotype with the Gc2 polymorphism of the DBP. Moreover, we found a quantitative reduction of Apolipoprotein A-I in mutant individuals, which was associated, in previous studies by others to an increased cardiovascular risk.