Methylenetetrahydrofolate Reductase CpG Islands: Epigenotyping

Epigenetics Mechanisms in Ischemic Stroke: A Promising Avenue?

Stroke has emerged as the second most common cause of mortality worldwide and is a major public health problem. It is a multi-factorial disease and genetics plays an important role in its pathophysiology, however, mechanisms of genome involvement in the disease remain unclear. Both genetic and epigenetic mechanisms could play a role in the development of stroke disease. Although epigenetic characteristics may also be heritable, they can be modified during the lifetime under different environmental exposure in response to lifestyle. Recent studies provide clear evidence that epigenetic factors play an important role in the pathological mechanisms leading to an elevated risk of cardiovascular diseases and stroke. Epigenetic changes are reversible therefore; studying epigenetic factors may serve as a marker for disease progression, biomarker for disease diagnosis, and development of novel targets for therapeutic intervention. Identifying the factors which predispose the risk of stroke provides information for the mechanism of stroke and the design of new drug targets where epigenetic modifications play a significant role. Epigenetic modifications play an essential role in a large variety of multifactorial diseases. This review will focus on the evidence that epigenetic mechanisms play a crucial role in the pathophysiology of ischemic stroke.

Application of the genetic risk model for the analysis of predisposition to nonlacunar ischemic stroke

Aim: The purpose of our study was to analyze the predictive ability of the multiplicative model of genetic risk of nonlacunar ischemic stroke (IS) for independent samples from Russia. Patients & methods: A total of 181 patients and 360 healthy controls were included in this study. The discriminative accuracy of model was evaluated by the area under the receiver operating characteristic curve (AUC). Results: Classification model based on 15 single-nucleotide polymorphisms (SNPs), which are associated with a cardioembolic subtype of IS, had an AUC of 0.62 in patients with corresponding subtypes and an AUC of 0.58 for all patients. Conclusion: Risk calculation approach based on IS-associated SNPs had satisfactory performance in predicting the predisposition to the disease.

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.