TPH1 and Stroke: Additionally, the presence of the G/G-T/T and G/A-T/T combined genotypes of the c.*456G > A (rs10988134) – KAT1 and c.-1668T > A – TPH1 (rs623580) polymorphisms reduced the risk of stroke development, while the G/G-T/A genotype increased this risk in the studied population.