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

The Genetic Basis of Strokes in Pediatric Populations and Insight into New Therapeutic Options

Strokes within pediatric populations are considered to be the 10th leading cause of death in the United States of America, with over half of such events occurring in children younger than one year of life. The multifactorial etiopathology that has an influence on stroke development and occurrence signify the importance of the timely recognition of both modifiable and non-modifiable factors for adequate diagnostic and treatment approaches. The early recognition of a stroke and stroke risk in children has the potential to advance the application of neuroprotective, thrombolytic, and antithrombotic interventions and rehabilitation strategies to the earliest possible timepoints after the onset of a stroke, improving the outcomes and quality of life for affected children and their families. The recent development of molecular genetic methods has greatly facilitated the analysis and diagnosis of single-gene disorders. In this review, the most significant single gene disorders associated with pediatric stroke are presented, along with specific therapeutic options whenever they exist. Besides monogenic disorders that may present with stroke as a first symptom, genetic polymorphisms may contribute to the risk of pediatric and perinatal stroke. The most frequently studied genetic risk factors are several common polymorphisms in genes associated with thrombophilia; these genes code for proteins that are part of the coagulation cascade, fibrolysis, homocystein metabolism, lipid metabolism, or platelets. Single polymorphism frequencies may not be sufficient to completely explain the stroke causality and an analysis of several genotype combinations is a more promising approach. The recent steps forward in our understanding of the disorders underlying strokes has given us a next generation of therapeutics and therapeutic targets by which to improve stroke survival, protect or rebuild neuronal connections in the brain, and enhance neural function. Advances in DNA sequencing and the development of new tools to correct human gene mutations have brought genetic analysis and gene therapy into the focus of investigations for new therapeutic options for stroke patients.

MTHFR A1298C gene polymorphism on stroke risk: an updated meta-analysis

Background

Previous studies have shown the effect of MTHFR A1298C gene polymorphism on stroke risk. But the results of published studies remained inconclusive and controversial. So we conducted a meta-analysis to accurately estimate the potential association between MTHFR A1298C gene polymorphism and stroke susceptibility.

Methods

A systematic literature search on Embase, Pubmed, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI) and WanFang electronic database identified 40 articles including 5725 cases and 8655 controls. Strength of association was evaluated by pooled odds ratio (OR), 95% confidence interval (CI) and p value. Funnel plots and Begger’s regression test were applied for testing the publication bias. Statistical analysis of all data was performed by Stata 12.0.

Results

The meta-analysis results indicated a significant relationship between MTHFR gene A1298C polymorphisms and stoke risk under the C allelic genetic model (OR = 1.19, 95%CI = 1.07–1.32, p = 0.001), dominant genetic model (OR = 1.19, 95%CI = 1.06–1.33, p = 0.004) and recessive genetic model (OR = 1.43, 95%CI =1.15–1.77, p = 0.001). In subgroup analysis, we discovered obvious correlation in three genetic model of Asian, stroke type, adult by ethnicity, population, stroke type, source of control and case size. Additionally, in studies of control from hospital and case size equal 100, obvious correlation was also found in the three genetic model.

Conclusions

Our meta-analysis results indicated that there was evidence to support the correlation between MTHFR A1298C polymorphism and stroke susceptibility, especially in adults and ischemic stroke.

Association of MTHFR 1298A > C Polymorphism with Susceptibility to Non-Syndromic Cleft Lip with or without Palate: A Case-Control Study and Meta-Analysis

BACKGROUND

Several studies have evaluated association of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene 1298A > C polymorphism with non-syndromic cleft lip with or without palate (NSCL ± P) susceptibility, however the results are inconsistent.

MATERIALS AND METHODS

To address this issue, we performed a case-control study to evaluate the association of MTHFR 1298A > C polymorphism with NSCL ± P risk, followed by a meta-analysis.

RESULTS

Including our study, a total of 22 case-control studies with 2,814 cases and 4,199 controls were selected. The results suggested that there was no significant association between MTHFR 1298A > C polymorphism and NSCL ± P risk overall. The subgroup analysis demonstrated that the polymorphism was significantly associated with NSCL ± P risk in Asians and Iranian populations, but not in Caucasians, mixed and Chinese populations.

CONCLUSION

This meta-analysis indicates that MTHFR 1298A > C polymorphism may not contribute to NSCL ± P risk in overall. However, the MTHFR 1298A > C polymorphism was significantly associated with an increased risk of NSCL ± P in Asians and Iranian populations.

Antiphospholipid syndrome and its role in pediatric cerebrovascular diseases: A literature review

Antiphospholipid syndrome (APS) or Hughes syndrome is an acquired thromboinflammatory disorder. Clinical criteria of APS diagnosis are large- and small-vessel thrombosis as well as obstetric problems; laboratory criteria are the presence of antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibodies and anti-β2-glycoprotein-1). The presence of at least 1 clinical and 1 laboratory criterion allows definitive diagnosis of APS. Primary APS is diagnosed in patients without features of connective tissue disease; secondary APS is diagnosed in patients with clinical signs of autoimmune disease. A high frequency of catastrophic APS as well as a high tendency to evolve from primary APS to secondary syndrome during the course of lupus and lupus-like disease is a feature of pediatric APS. The most characteristic clinical presentation of APS in the pediatric population is venous thrombosis, mainly in the lower limbs, and arterial thrombosis causing ischemic brain stroke. Currently, no diagnostic criteria for pediatric APS exist, which probably results in an underestimation of the problem. Similarly, no therapeutic procedures for APS specific for children have yet been established. In the present literature review, we discussed data concerning APS in children and its role in cerebrovascular diseases, including pediatric arterial ischemic stroke, migraine and cerebral venous thrombosis.

Risk Factors for Recurrent Arterial Ischemic Stroke in Children and Young Adults

Arterial ischemic stroke (AIS) experienced at a young age is undoubtedly a serious medical problem. AIS very rarely occurs at a developmental age, whereas in young adults, it occurs with a higher frequency. The etiologic mechanisms of AIS occurring in childhood and adulthood differ. However, for both age populations, neurological consequences of AIS, including post-stroke seizures, motor disability, and recurrence of the disease, are connected to many years of care, rehabilitation, and treatment. Recurrent stroke was observed to increase the risk of patients' mortality. One of the confirmed risk factors for recurrent stroke in children is the presence of vasculopathies, especially Moyamoya disease and syndrome, and focal cerebral arteriopathy of childhood (FCA). FCA causes a 5-fold increase in the risk of recurrent stroke in comparison with idiopathic AIS. In turn, young adults with recurrent stroke were found to more often suffer from hypertension, diabetes mellitus, or peripheral artery disease than young patients with first-ever stroke. Some reports also indicate relationships between specific genetic polymorphisms and AIS recurrence in both age groups. The aim of the present literature review was to discuss available data regarding the risk factors for recurrent AIS in children and young adults.

Lack of Associations Between PAI-1 and FXIII Polymorphisms and Arterial Ischemic Stroke in Children: A Systematic Review and Meta-Analysis

The role of genetic risk factors for ischemic stroke seems to be in particular significance in pediatric patients. Numerous polymorphic variants of genes encoding proteins, that is, plasminogen activator inhibitor as well as coagulation factors, involved in the coagulation cascade may be related to arterial ischemic stroke (AIS) both in adults and children. We performed systematic review and 2 meta-analyses to assess possible correlations between common plasminogen activator inhibitor (PAI-1) and FXIII polymorphisms and ischemic stroke in children. We searched PubMed to identify available data published before October 2018 using appropriate keywords and inclusion criteria. Finally, 12 case-control studies were included: 8 analyzing PAI-1 polymorphism (600 children with stroke and 2152 controls) and 4-FXIII polymorphism (358 children with stroke and 451 controls). R and Comprehensive Meta-Analysis software were used to analyze the impact of the particular polymorphism in the following models: dominant, recessive, additive, and allelic. No publication bias was observed in both meta-analyses. In case of PAI-1 polymorphism, we observed no relation between 4G4G genotype of 4G allele and ischemic stroke in children. We also demonstrated lack of association between FXIII polymorphism and childhood ischemic stroke. In children with AIS, the PAI-1 and FXIII polymorphisms are not risk factors for the disease.

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.