The methylenetetrahydrofolate reductase polymorphism (MTHFR c.677C>T) and elevated plasma homocysteine levels in a U.S. pediatric population with incident thromboembolism

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.

Association of Thymidylate Synthase (TS) Gene Polymorphisms with Incidence and Prognosis of Coronary Artery Disease

Coronary artery disease (CAD) is a prevalent cardiovascular condition characterized by the accumulation of plaque within coronary arteries. While distinct features of CAD have been reported, the association between genetic factors and CAD in terms of biomarkers was insufficient. This study aimed to investigate the connection between genetic factors and CAD, focusing on the thymidylate synthase (TS) gene, a gene involved in DNA synthesis and one-carbon metabolism. TS plays a critical role in maintaining the deoxythymidine monophosphate (dTMP) pool, which is essential for DNA replication and repair. Therefore, our research targeted single nucleotide polymorphisms that could potentially impact TS gene expression and lead to dysfunction. Our findings strongly associate the TS 1100T>C and 1170A>G genotypes with CAD susceptibility. We observed that TS 1100T>C polymorphisms increased disease susceptibility in several groups, while the TS 1170A>G polymorphism displayed a decreasing trend for disease risk when interacting with clinical factors. Furthermore, our results demonstrate the potential contribution of the TS 1100/1170 haplotypes to disease susceptibility, indicating a synergistic interaction with clinical factors in disease occurrence. Based on these findings, we propose that polymorphisms in the TS gene had the possibility of clinically useful biomarkers for the prevention, prognosis, and management of CAD in the Korean population.

Homozygous methylentetrahydrofolate reductase C667T genotype anticipates age at venous thromboembolism by one decade

The aim of the study was to compare age at first venous thromboembolism (VTE), plasma homocysteine and activated partial thromboplastin time ratio (aPTTr) amongst unprovoked VTE patients with the methylentetrahydrofolate reductase (MTHFR) C667T genotypes, and to identify predictors of age at first VTE, of plasma homocysteine and of the aPTTr; to evaluate whether heterozygous or homozygous prothrombin (PT) G20210A mutation lowered the age at first VTE when associated with MTHFR TT. Retrospective cohort study on 259 MTHFR TT, 76 MTHFR TC and 64 MTHFR CC participants with unprovoked VTE; each participant contributed age, sex, age at VTE, history of dyslipidaemia, hypertension, smoking, homocysteine (measured by enzyme immunoassay) and aPTTr (measured by standard coagulation assay). Age at first VTE was lower in MTHFR TT than MTHFR TC and CC (41 ± 14 vs. 50 ± 16 vs. 51 ± 12 years, respectively, P < 0.0001); plasma homocysteine was higher in MTHFR TT than in the other groups (22 ± 21 vs. 12 ± 11.6 vs. 10 ± 3.3 μmol/l, respectively, P = 0.0005) whilst aPTTr was not different. MTHFR TT independently predicted age at first VTE (P = 0.001), plasma homocysteine (P < 0.0001) alongside sex (P = 0.0007), age and smoking (P = 0.03 for both). Compound MTHFR TT with PT GA or AA had no lowering effect on age at first VTE compared with MTHFR TT alone (41 ± 13 vs. 41 ± 14 years). Plasma homocysteine inversely related to aPTTr in the MTHFR TT group (P = 0.003). MTHFR TT anticipates age at first VTE by an average of 10 years compared with MTHFR TC and CC genotypes.

The 3'-UTR Polymorphisms in the Thymidylate Synthase (TS) Gene Associated with the Risk of Ischemic Stroke and Silent Brain Infarction

Thymidylate synthase (TS) is a key gene involved in the repair of DNA damage and DNA synthesis that plays an important role in vascular development and recovery. In particular, TS gene polymorphisms play a major role in the progression of vascular disease and cancer metastasis. Therefore, the aim of this study was to investigate the association of three TS polymorphisms (1100T>C [rs699517], 1170A>G [rs2790], and 1494ins/del [rs151264360]) with ischemic stroke and silent brain infarction (SBI) in Koreans. A total of 1299 participants (507 stroke patients, 383 SBI patients, and 409 controls) were enrolled in the study. Genotyping of the three TS polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism analysis. To examine the association between TS gene polymorphisms and the diseases, we performed statistical analyses, including multivariable logistic regression and Fisher's exact tests. We found that TS 1100T>C and 1170A>G genotypes were strongly associated with ischemic stroke and SBI susceptibility. More specifically, the TS 1100T>C polymorphism was associated with the likelihood of ischemic stroke (TT vs. CC: AOR = 2.151, 95% CI = 1.275-3.628, P = 0.004) and SBI (TT vs. TC+CC: AOR = 1.443, 95 % CI = 1.009-2.063, P = 0.045). In contrast, the TS 1170A > G polymorphism exhibited lower correlation with the risk of stroke (AA vs. GG: AOR = 0.284, 95% CI = 0.151-0.537, P < 0.0001) and SBI (AA vs. GG: AOR = 0.070, 95% CI = 0.016-0.298, P = 0.0002). Furthermore, we confirmed that the TS 1100T>C polymorphism was synergistic with low folic acid levels (AOR = 6.749, P < 0.0001). Altogether, these results suggest that TS 1100T>C and 1170A > G polymorphisms are associated with the risk of ischemic stroke and SBI, and our study provides the first evidence that 3'-UTR variants in TS are potential biomarkers in ischemic stroke and SBI.

Alterations in Sulfur Amino Acids as Biomarkers of Disease

Homocysteine (Hcy) is methylated by methionine synthase to form methionine with methyl-cobalamin as a cofactor. The reaction demethylates 5-methyltetrahydrofolate to tetrahydrofolate, which is required for DNA and RNA synthesis. Deficiency of either of the cobalamin (Cbl) and/or folate cofactors results in elevated Hcy and megaloblastic anemia. Elevated Hcy is a sensitive biomarker of Cbl and/or folate status and more specific than serum vitamin assays. Elevated Hcy normalizes when the correct vitamin is given. Elevated Hcy is associated with alcohol use disorder and drugs that target folate or Cbl metabolism, and is a risk factor for thrombotic vascular disease. Elevated methionine and cystathionine are associated with liver disease. Elevated Hcy, cystathionine, and cysteine, but not methionine, are common in patients with chronic renal failure. Higher cysteine predicts obesity and future weight gain. Serum S-adenosylhomocysteine (AdoHcy) is elevated in Cbl deficiency and chronic renal failure. Drugs that require methylation for catabolism may deplete liver S-adenosylmethionine and raise AdoHcy and Hcy. Deficiency of Cbl or folate or perturbations of their metabolism cause major changes in sulfur amino acids.

Is an "Epigenetic Diet" for Migraines Justified? The Case of Folate and DNA Methylation

Migraines are a common disease with limited treatment options and some dietary factors are recognized to trigger headaches. Although migraine pathogenesis is not completely known, aberrant DNA methylation has been reported to be associated with its occurrence. Folate, an essential micronutrient involved in one-carbon metabolism and DNA methylation, was shown to have beneficial effects on migraines. Moreover, the variability of the methylenetetrahydrofolate reductase gene, important in both folate metabolism and migraine pathogenesis, modulates the beneficial effects of folate for migraines. Therefore, migraine could be targeted by a folate-rich, DNA methylation-directed diet, but there are no data showing that beneficial effects of folate consumption result from its epigenetic action. Furthermore, contrary to epigenetic drugs, epigenetic diets contain many compounds, some yet unidentified, with poorly known or completely unknown potential to interfere with the epigenetic action of the main dietary components. The application of epigenetic diets for migraines and other diseases requires its personalization to the epigenetic profile of a patient, which is largely unknown. Results obtained so far do not warrant the recommendation of any epigenetic diet as effective in migraine prevention and therapy. Further studies including a folate-rich diet fortified with valproic acid, another modifier of epigenetic profile effective in migraine prophylaxis, may help to clarify this issue.

Pediatric Stroke: A Single-Center Experience

The aim of this study was to evaluate the clinical characteristics, risk factors, treatment, and outcomes of pediatric stroke cases. A total of 118 patients diagnosed with arterial ischemic stroke (AIS), hemorrhagic stroke, and sinovenous thrombosis (SVT) between January 2000 and December 2011 were included. Neonatal cases were excluded. Demographic and clinical findings were retrospectively examined from medical records. We identified 118 patients with stroke. The age of the patients ranged from 1 to 215 months (17.92 y), with a mean age of 5.19±5.25 years. AIS accounted for the majority of cases (n=69, 58.5%), and the major etiology was cardiac disease (17%). Hemorrhagic stroke accounted for 19.5% (n=23) of the cases, and late hemorrhagic disease of the newborn was the major etiology (43%, n=10). SVT accounted for 22% (n=26) of the cases, and the major etiology was otitis media-mastoiditis (27%, n=7). Hemiplegia and headache were the most frequent symptoms for AIS and SVT, respectively. Stroke is rare in children compared with adults; however, it is detected more frequently with better imaging techniques and increased awareness. We found that children with AIS presented more commonly with hemiplegia and children with SVT with headache and strabismus. We did not find an association between thrombophilia and stroke.

Is the 1298A>C polymorphism in the MTHFR gene a risk factor for arterial ischaemic stroke in children? The results of meta-analysis

An elevated level of homocysteine is a risk factor for vascular diseases, brain atrophy and several other disorders. The 1298A>C polymorphism (rs1801131) leads to mildly decreased MTHFR activity. Previously, it was observed that the MTHFR 1298A>C polymorphism in combined analysis with the MTHFR 677C>T polymorphism increases homocysteine levels. However, conflicting results on its relation to ischaemic stroke in children can be found. We conducted a meta-analysis to analyse possible connections between the MTHFR 1298A>C polymorphism and ischaemic stroke in paediatric patients. We identified available data published before December 2016 using appropriate keywords and searching PubMed as well as the references cited in the found articles. Eight case-control studies were included in the meta-analysis (426 children with stroke and 778 controls). Statistical analyses were made using R and Comprehensive Meta-Analysis softwares to investigate the impact of polymorphism in four models: dominant, recessive, additive and allelic. No publication bias was observed in the meta-analysis. We demonstrated no relationship between the 1298A>C polymorphism and ischaemic stroke in children in the case of recessive, additive and allelic models. However, the results of the dominant model analysis should be treated with caution due to the sensitivity analysis results. After omitting one of the included study, we observed a significant association between the carriers of the MTHFR C allele (cases with AC + CC genotypes) and ischaemic stroke in children (OR 1.35 95% CI 1.02-1.79, p = 0.035 in a fixed effects model). In conclusion, the 1298A>C polymorphism in the MTHFR gene is not a risk factor for ischaemic stroke in paediatric patients.

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

Stroke incidence is a multifactorial disease and especially hyperhomocysteinemia is associated with a higher risk of stroke. Previous studies have reported a folate metabolism disorder associated with the MTHFR gene. We investigated four single nucleotide polymorphisms in the MTHFR 3'-UTR [2572 C > A (rs4846049), 4869 C > G (rs1537514), 5488 C > T (rs3737967), and 6685 T > C (rs4846048)] to elucidate associations between ischemic stroke prevalence and prognosis. We examined 511 consecutive patients with ischemic stroke. Additionally, we selected 411 sex-/age-matched control subjects from patients presenting at our hospitals during the same period. The MTHFR 2572 C > A and 6685 T > C were significantly associated with ischemic stroke prevalence in the cardioembolism subgroup (MTHFR 2572CC vs. CA + AA: AOR, 2.145; 95% CI, 1.203-3.827; P = 0.010; MTHFR 6685TT vs. CC: AOR, 10.146; 95% CI, 1.297-79.336; P = 0.027). The gene-environment combined effect was significant, with MTHFR 2572CA + AA and folate levels ≤3.45 ng/mL correlating with ischemic stroke incidence. In addition, the total homocysteine (tHcy) levels in subjects with MTHFR 2572AA were elevated compared to tHcy levels in subjects with MTHFR 2572CC. Therefore, we suggest that MTHFR 2572 C > A and 6685 T > C are associated with ischemic stroke pathogenesis. The combined effects of the MTHFR 3'-UTR polymorphisms and tHcy/folate levels may contribute to stroke prevalence.

Major Polymorphisms of Genes Involved in Homocysteine Metabolism in Malaria Patients in Ouagadougou, Burkina Faso

This study analyzed the four main polymorphisms of the genes in homocysteine metabolism in malaria patients. Forty-two randomly selected subjects, diagnosed positive for Plasmodium falciparum, were included. The four genotypes were detected by real-time PCR using the MTHFR 677C>T, MTHFR 1298A>C, MTR 2756A>G, and MTRR 66A>G detection kit (Sacace Biotechnologies REF: T01002-96-S). The results revealed frequencies of 90% 677CC, 10% 677CT, and 00% 677TT for MTHFR C677T; 78.6% 1298AA, 19% 1298AC, and 2.4% 1298CC for MTHFR A1298C; 61.9% 2756AA, 33.3% 2756AG, and 4.8% 2756GG for MTR A2756G; and 50% of 66AA, 45% of 66AG, and 5% of 66GG for MTRR A66G. Correlations were found between A2756G MTR genotypes and parasitaemia (P = 0.02), MTRR A66G and hemoglobin genotypes (P = 0.009), and MTHFR A1298C and sex (P = 0.01). This study demonstrated for the first time an association between the A2756G MTR alleles and Plasmodium falciparum malaria in Burkina Faso and gave an overview of the genotypic distribution of the major SNPs influencing the metabolism of homocysteine.

Thrombophilia risk is not increased in children after perinatal stroke

Thrombophilia in children with perinatal stroke is rare, with rates similar to those in the normal population. Routine testing in childhood is not indicated.

Arterial Ischemic Stroke in Children and Young Adults

PURPOSE OF REVIEW

This article reviews risk factors, recurrence risk, evaluation, management, and outcomes of arterial ischemic stroke in children and young adults.

RECENT FINDINGS

The risk for recurrence and mortality appear to be low for neonatal and childhood stroke. Most children have relatively mild deficits, but those who have greater neurologic deficits, poststroke epilepsy, or strokes early in life are at risk for lower overall cognitive function. Stroke recurrence and long-term mortality after stroke in young adults are greater than originally thought. Cognitive impairments, depression, and anxiety are associated with higher levels of poststroke unemployment and represent targets for improved poststroke care. Poststroke care in young adults involves more than medical management. Self-reported memory and executive function impairments may be more severe than what is detected by objective measures. Assessment of possible cognitive impairments and appropriate management of psychological comorbidities are key to maximizing the long-term functional outcome of stroke survivors.

SUMMARY

Childhood and young adult stroke survivors survive for many more years than older patients with stroke. To ensure that these survivors maximize the productivity of their lives, neurologists must not only optimize medical management but also recognize that impairments in cognition and mood may be remediable barriers to long-term functional independence.

Renal vascular thrombosis in the newborn

Neonatal renal vascular thrombosis is rare but has devastating sequelae. The renal vein is more commonly affected than the renal artery. Most neonates with renal vein thrombosis present with at least one of the three cardinal signs, namely, abdominal mass, macroscopic hematuria and thrombocytopenia, while unilateral renal artery thrombosis presents with transient hypertension. Contrast angiography is the gold standard for diagnosis but because of exposure to radiation and contrast agents, Doppler ultrasound scan is widely used instead. Baseline laboratory tests for platelet count, prothrombin time, activated partial thromboplastin time and fibrinogen concentration are essential before therapy is initiated. Maternal blood is tested for lupus anticoagulant and anticardiolipin antibody. Evaluation for prothrombotic disorders is warranted when thrombosis is clinically significant, recurrent or spontaneous. Management should involve a multidisciplinary team that includes neonatologists, radiologists, pediatric hematologists and nephrologists. In addition to supportive therapy, recent guidelines recommend at least prophylactic heparin therapy in the majority of cases to prevent thrombus extension. Thrombolytic therapy is reserved for bilateral thrombosis compromising kidney function. Long-term sequelae, such as kidney atrophy, systemic hypertension and chronic kidney disease, are common, and follow-up by pediatric nephrologists is recommended for monitoring of kidney function, early detection and management of hypertension and chronic kidney disease.

Potential Risk Factors Associated With Vascular Diseases in Patients Receiving Treatment for Hypertension

Background

Currently, the hypertension (HTN) patients undergo appropriate medical treatment, and traditional risk factors are highly controlled. Therefore, potential risk factors of atherosclerotic vascular diseases (AVD) and venous thromboembolisms (VTE) in HTN should be reconsidered. We investigated thrombophilic genetic mutations and existing biomarkers for AVD or VTE in HTN patients receiving treatment.

Methods

A total of 183 patients were enrolled: AVD with HTN (group A, n=45), VTE with HTN (group B, n=62), and HTN patients without any vascular diseases (group C, n=76). The lipid profile, homocysteine (Hcy) levels, D-dimers, fibrinogen, antithrombin, lupus anticoagulant, and anti-cardiolipin antibody (aCL) were evaluated. Prothrombin G20210A, Factor V G1691A, and methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C were analyzed.

Results

All patients revealed wild type prothrombin G20210A and Factor V G1691A polymorphisms. The frequency of MTHFR polymorphisms was 677CT (n=84, 45.9%); 677TT (n=46, 25.1%); 1298AC (n=46, 25.1%); and 1298CC (n=2, 1.1%). The MTHFR 677TT genotype tended to increase the odds ratio (OR) to AVD events in HTN patients (OR 2.648, confidence interval 0.982-7.143, P=0.05). The group A demonstrated significantly higher Hcy levels (P=0.009), fibrinogen (P=0.004), and platelet counts (P=0.04) than group C. Group B had significantly higher levels of D-dimers (P=0.0001), platelet count (P=0.0002), and aCL (P=0.02) frequency than group C.

Conclusions

The MTHFR 677TT genotype and Hcy level could be potential risk factors associated with development of AVD in HTN patients receiving treatment. D-dimer and aCL might be useful to estimate the occurrence of VTE in them.

The MTHFR C677T Polymorphism and Risk of Intracerebral Hemorrhage in a Chinese Han Population

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism has been speculated to be and extensively investigated as a risk factor for various vascular diseases, including intracerebral hemorrhage (ICH). However, results from published studies regarding the role of C677T polymorphism in ICH risk in Chinese populations were contradictory rather than conclusive.

MATERIAL/METHODS

In this study, a total of 180 ICH patients and 180 matched controls of Chinese Han ethnicity were enrolled. The MTHFR C677T polymorphism was genotyped by polymerase chain reaction-ligation detection reaction (PCR-LDR). A meta-analysis was conducted by combining our data with previous relevant studies in Chinese populations.

RESULTS

In our case-control study, similar allele frequency (p=0.492) and genotype distribution (p=0.748) of MTHFR C677T polymorphism were detected between ICH patients and controls. Further analysis based on hematoma location did not show a significant association. When combined with previous studies, however, C677T polymorphism was found to be significantly associated with an increased risk for ICH in Chinese populations (recessive model: OR=1.57, 95%CI=1.29-1.91). When focusing on the Han ethnicity, carriers of the TT genotype had an increased risk of ICH (recessive model: OR=1.36, 95%CI=1.05-1.75).

CONCLUSIONS

In this case-control study we did not observe that the MTHFR C677T polymorphism was associated with ICH risk in people of Chinese Han ethnicity. However, when combined with previous published studies, a significant association of C677T polymorphism with an increased risk of ICH was detected in Chinese populations, and also in the subgroup analysis focusing on Han ethnicity.

VKORC1 -1639 G>A Polymorphism in Romanian Patients With Deep Vein Thrombosis

AIM

The purpose of the research was to study the influence of several genetic factors, especially the -1693 G>A polymorphism of the VKORC1 gene, on the risk of acute unprovoked lower extremity deep vein thrombosis (DVT).

MATERIALS AND METHODS

The study included 127 patients (median age 63 [53.2; 72] years; 61 [48%] women and 66 [52%] men) who were diagnosed with acute lower extremity DVT and 114 controls (median age 62 [53; 73] years; 64 [56.1%] women and 50 [43.9%] men) without DVT. We recorded data regarding the history of DVT and the presence of varicose veins. We determined the genotypes for factor V Leiden (FVL) mutation, prothrombin G20210A mutation, VKORC1 -1639 G>A mutation, and PAI-1 -675 4G/5G polymorphism.

RESULTS AND CONCLUSION

Varicose veins were found in 67 (52.8%) patients and 29 (25.4%) controls (P < .001). FVL was present in 29 (22.8%) patients and 10 (8.8%) controls (P = .005). The VKORC1 (-1693 G>A) GG genotype was found in 42 (33.1%) patients and 41 (36%) controls, the GA genotype in 71 (55.9%) patients and 47 (41.2%) controls, and AA genotype in 14 (11%) patients and 26 (22.8%) controls (P = .020). Multivariate analysis showed that the presence of varicose veins, FVL, and VKORC1 -1639 G>A was independently associated with the risk of DVT. The VKORC1 (-1693 G>A) AA genotype was associated with fewer cases of DVT (odds ratio = 0.435; 95% confidence interval 0.205-0.991; P = .031).

Arterial ischemic stroke in children: risk factors and etiologies

Stroke is increasingly recognized as a significant cause of morbidity and mortality in children, and as a financial burden for families and society. Recent studies have identified and confirmed presumptive risk factors, and have identified novel associations with childhood arterial ischemic stroke. A better understanding of risk factors for stroke in children, which differ from the atherosclerotic risk factors in adults, is the first step needed to improve strategies for stroke prevention and intervention, and ultimately minimize the physical, mental, and financial burden of arterial ischemic stroke. Here, we discuss recent advances in research for selected childhood stroke risk factors, highlighting the progress made in our understanding of etiologic mechanisms and pathophysiology, and address the future directions for acute and long-term treatment strategies for pediatric stroke.