MTHFR and ischemic stroke: Furthermore, Table 2 also shows that patients with low PCT (Q1) and normal MTHFR 677 genotype (CC/CT) subgroups receiving folic acid reduced 60% (HR: 0.40; 95% CI: 0.23–0.70; p = 0.001) and 70% (HR: 0.30; 95% CI: 0.16–0.57; p < 0.001) stroke and ischemic stroke risk during the trial period, respectively.