Lack of association between methylenetetrahydrofolate reductase (MTHFR) C677T and ischaemic heart disease (IHD): family-based association study in a Spanish population

Association between polymorphism of MTHFR c.677C>T and risk of cardiovascular disease in Turkish population: a meta-analysis for 2.780 cases and 3.022 controls

Cardiovascular diseases (CVDs) remain the main cause of morbidity and mortality around the world. A common polymorphism c.677C>T has been identified in the gene coding for methylenetetrahydrofolate reductase (MTHFR), which is involved in the remethylation of homocysteine, and may predispose to CVDs. A meta-analysis was performed to estimate the risk of CVDs associated with MTHFR c.677C>T in Turkish population. Published studies were retrieved from PubMed, Science Citation Index/Expanded, Google Scholar, Turkish Medline, and the Turkish Council of Higher Education Theses Database. For each study, we calculated odds ratios and 95 % confidence intervals (CI), assuming frequency of allele and homozygote comparison, dominant and recessive genetic models. Thirty-one separate studies were included and 2.780 cases/3.022 controls were involved in the current meta-analysis. Significant association was found between c.677C>T polymorphism and risk of CVD when all studies pooled with random-effects model for T versus C (OR 1.33; 95 % CI 1.11-1.59; p = 0.002), TT vs. CC (OR 1.87; 95 % CI 1.35-2.60; p = 3.53E-04), TT+CT vs. CC (OR 1.32; 95 % CI 1.06-1.64; p = 0.014) and TT vs. CT+CC (OR 1.75; 95 % CI 1.29-2.37; p = 6.57E-04). Further analysis indicated the significant association between methylenetetrahydrofolate reductase (MTHFR) TT genotype and groups with venous thrombosis, peripheral arterial thrombosis, acute MI/MI. No publication bias was observed in any comparison model. Our results of meta-analysis suggest that MTHFR c.677C>T polymorphism is associated with the CVDs in Turkish population.

An MTHFR variant, plasma homocysteine levels and late-onset coronary artery disease in subjects from southern Iran

There have been many controversial debates on the role of Hyperhomocysteinaemia (HHcy) as an independent risk factor for Coronary Artery Disease (CAD) during recent years. Furthermore, an alanine/valine (Ala/Val) gene polymorphism at 222nd amino acid of 5,10-methylenetetrahydrofolate reductase (MTHFR) has been considered as a factor that could render this enzyme thermolabile and less active which in turn may yield a subsequent increase in plasma total homocysteine (tHcy) levels. To assess whether this polymorphism is associated with increased risk of CAD and plasma levels of tHcy in a population from southern Iran, a total of 457 patients with angiographically documented multi-vessel CAD were compared with a control group comprised of 371 subjects with <30% stenosis in all major vessels. Nevertheless our results failed to admit a significant difference between CAD individuals and control subjects for Ala/Val polymorphism and plasma Hcy concentrations. However, plasma Hcy concentrations were significantly higher in individuals with Val/Val genotype than subjects with Ala/Ala genotype, but it didn't show a significant association with CAD in our population. Moreover, as the multiple linear regression analysis indicated, smoking habit, folate levels and the MTHFR Val/Val genotype were the only major predictors of tHcy concentrations in the current investigation.

E65 K polymorphism in KCNMB1 gene is not associated with ischaemic heart disease in Spanish patients

Hypertension is a main risk factor for atherosclerosis through vascular wall hyperplasia. A recent study reported a new polymorphism (E65 K) in the beta(1) subunit (KCNMB1) gene of the Ca(2+)-dependent potassium channel with a protective effect against the severity of diastolic hypertension, but further data have lead to conflicting results. In order to ascertain the involvement of the E65 K variant in cardiovascular system regulation, the potential association between this mutation and ischaemic heart disease was assessed through a family-based association study (n=302 individuals). Transmission disequilibrium analysis failed to detect any association between this polymorphism and ischaemic heart disease. Although a minor effect cannot be discarded, sample analytical power and negative results do not support a major role for E65 K polymorphism in atherogenic pathologies.

Frecuencia de la mutación 677C-T del gen de la metilentetrahidrofolato reductasa en una muestra de 652 recién nacidos de toda España

BACKGROUND AND OBJECTIVE

An international study on the frequency of the mutation 677C-T of the methylenetetrahydrofolate reductase (MTHFR) gene and its genotypes has been performed on a sample of consecutive liveborn infants around the world. In that study Spain participated through the ECEMC group. Here we present the distribution of the frequency of the T-allele by Spanish Regions (Autonomic Comunities).

SUBJECTS AND METHOD

The ECEMC collaborating physicians gathered blood samples from 15 consecutive liveborn infants in 67 hospitals from all over the country during the same months, specifying the ethnicity and sex of each infant. The frequency of the mutation was estimated through the percentage with its confidence interval. The *2 of homogeneity (k-1 degrees of freedom) was used to confirm that the frequencies were not statistically different across the country.

RESULTS

The frequency distribution of the TT genotype does not differ significantly between Spanish Regions.

CONCLUSIONS

This seems to be the first nation-wide study on a homogeneous sample of individuals. The observed frequencies are in agreement with those observed in some published studies on specific Spanish geographic areas. The overall frequency is similar to that reported in Mediterranean countries.