Moreover, the G/G-G/G combined genotypes of c.*456G > A (rs10988134) – KAT1 and c.-844G > T – TPH2 (rs4570625) caused a more than elevenfold increase of the risk in the Polish population (p < 0.001), whereas the G/G-G/T and G/A-G/T genotypes caused a reduction of stroke occurrence. This evidence concerns the gene TPH2 and Stroke.