Hyperhomocysteinemia, MTHFR 677C-->T polymorphism, and stroke

A systematic review and meta-analysis expounding the relationship between methylene tetrahydrofolate reductase gene polymorphism and the risk of intracerebral hemorrhage among populations

Background: The relationship between methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphism with the risk of intracerebral hemorrhage (ICH) has remained to be controversial in recent years. This meta-analysis is aimed to confirm the association of these.

Methods: Systematically searching the related studies from the PubMed, Embase, Cochrane Library, China national knowledge internet database from 1 January 1990 to 1 June 2022. The odd ratio (ORs) and 95% confidence interval (CIs) of gene-disease correlation in various gene models were calculated by fixed or random effect model of meta-analysis. We included 20 case-control studies in this meta-analysis with a total of 1,989 ICH patients and 4,032 health controls originated from Asian, Caucasian, and African populations.

Results: The statistical analysis demonstrated the association of MTHFR C677T gene polymorphism with ICH in allele model [OR_{T VS. C} = 1.20 (95%CI: 1.06–1.36)]; homozygote model [OR _{TT VS. CC} = 1.50 (95%CI: 1.20–1.88)]; dominant model [OR _{CT+ TT VS. CC} = 1.23 (95%CI: 1.03–1.48)] and recessive model [OR_{TT VS. CT+CC} = 1.37 (95%CI: 1.17–1.60)]. Besides, we also found the relationship of MTHFR C677T gene polymorphism with Asian in four comparison model (OR_{T VS. C} = 1.19.95%CI:1.09–1.37, OR_{TT VS. CC} = 1.46.95%CI: 1.15–1.85, OR _{CT+ TT VS. CC} = 1.25.95%CI: 1.01–1.54, OR_{TT VS. CT+CC} = 1.34.95%CI: 1.54–1.17) and Caucasian in four comparison model (OR_{T VS. C} = 1.90.95%CI: 1.22–2.97, OR_{TT VS. CC} = 2.67.95%CI: 1.42–5.00, OR _{CT+ TT VS. CC} = 1.56.95%CI: 1.05–2.32, OR_{TT VS. CT+CC} = 2.25.95%CI: 1.46–4.00). But no statistically significant correlation between A1298C polymorphism and the occurrence of ICH was detected in four studies.

Conclusion: MTHFR C677T gene polymorphism increases the risk of ICH in Asian and Caucasian populations but has no impact on the incidence in African communities. More importantly, the risk of ICH increases in TT genotype individuals in comparison to CT and CC genotype individuals in Asian and Caucasian populations.

Acute stroke in relation to homocysteine and methylenetetrahydrofolate reductase gene polymorphisms

AIM

Some methylenetetrahydrofolate reductase (MTHFR) gene mutations cause hyperhomocysteinemia and homocystinuria. These may be important risk factors for cardio and cerebrovascular diseases. We investigated whether the MTHFR C677T and A1298C polymorphisms contribute to hyperhomocysteinemia and increase the risk factor for stroke.

METHODS

A total of 203 acute stroke patients and 55 controls were recruited. Polymorphisms were determined by using polymerase chain reaction-restriction fragment length polymorphism (RFLP) and plasma total homocysteine levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS AND CONCLUSIONS

There were no significant differences between C677T and A1298C genotypes and allele frequencies in the stroke patients and controls. Total plasma homocysteine level was higher in the 677TT and 1298AA genotypes in stroke patients and especially small-vessel disease patient subgroup. Age, number of males, systolic-diastolic blood pressures, creatinine, vitamin B(12) and homocysteine levels were significantly high among stroke patients. Age, sex, systolic blood pressure and HDL-C were determined as risk factors for homocysteine levels. We also determined that the effect of A1298C polymorphism on homocysteine was not as high as that of C677T polymorphism in acute stroke patients. We conclude that the MTHFR genotype may be a modest risk factor for stroke in Turkish population.