Hyperhomocysteinemia is a risk factor of recurrent coronary event in young patients irrespective to the MTHFR C677T polymorphism

Methylenetetrahydrofolate Reductase Polymorphism and Premature Coronary Artery Disease

Methylenetetrahydrofolate reductase (MTHFR) catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a co-substrate for homocysteine re-methylation to methionine. Its deficiency leads to an increased serum level of homocysteine, which is well-known to be associated with premature coronary artery disease (CAD). Our case demonstrates the association of MTHFR polymorphism with premature CAD and myocardial infarction (MI) despite normal homocysteine levels. Screening for MTHFR polymorphisms in addition to homocysteine levels may be considered for patients presenting with premature CAD and a normal lipid profile. Aggressive risk reduction with lifestyle modifications and guideline-driven medical therapy supplementation might be necessary for secondary cardiovascular disease prevention until more specific therapeutic options are available for this subgroup of patients.

High plasma homocysteine levels contribute to the risk of stroke recurrence and all-cause mortality in a large prospective stroke population

Plasma homocysteine concentrations have been associated with the risk of stroke, but its relevance to secondary vascular events and mortality after stroke remains unclear because of inconsistent results from clinical trials. The aim of the present study was to investigate whether plasma homocysteine levels and the MTHFR (methylenetetrahydrofolate reductase) variant C677T contributed to the risk of stroke recurrence and all-cause mortality in a large prospective cohort of stroke patients in a Chinese population. A total of 1823 stroke patients (age, 35-74 years) were recruited during 2000-2001 and prospectively followed-up for a median of 4.5 years. During the follow-up, 347 recurrent strokes and 323 deaths from all-causes were documented. After adjustment for age, gender and other cardiovascular risk factors, a high homocysteine concentration was associated with an increased risk of 1.74-fold for stroke recurrence {RR (relative risk), 1.74 [95% CI (confidence interval), 1.3-2.3]; P<0.0001} and 1.75-fold for all-cause mortality [RR, 1.75 (95% CI, 1.3-2.4); P<0.0001] when highest and lowest categories were compared. Spline regression analyses revealed a threshold level of homocysteine for stroke recurrence. By dichotomizing homocysteine concentrations, the RRs were 1.31 (95% CI, 1.10-1.61; P=0.016) for stroke recurrence and 1.47 (95% CI, 1.15-1.88; P<0.0001) for all-cause mortality in patients with homocysteine levels > or =16 micromol/l relative to those with levels <16 micromol/l. The association of elevated plasma homocysteine concentrations with all-cause mortality was mainly due to an increased risk of cardiovascular deaths. No significant association was found between MTHFR C677T and stroke recurrence or mortality. In conclusion, our findings suggest that elevated homocysteine concentrations can predict the risk of stroke recurrence and mortality in patients with stroke.