In the case of the c.-1849C > A – IDO1 (rs3824259) and c.804-7C > A – TPH1 (rs1799913) polymorphisms, the C/C-C/A and C/A-C/A combined polymorphisms were linked with a reduction of stroke risk about 20 times (p = 0.004) and 10 times (p < 0.001), respectively. This evidence concerns the gene IDO1 and Stroke.