We reported a case of two 24-year-old and 17-year-old male patients with episode of transient ischemic attacks and diagnosed as having patent foramen ovale (PFO). One patient had heterozygosity for the factor V Leiden mutation, and one other had heterozygosity for prothrombin G20210A mutation. Both of them were also carriers for MTHFR 677T genotype with elevated plasma levels of homocysteine (22.3 +/- 3.9 micromol/L). These findings strongly confirm and emphasize the importance of the genetic screening for thrombotic mutations in young patients with PFO-related ischemic events in order to improve secondary prevention strategies.