Due to the higher selectivity and specificity of the S enantiomer compared with the R enantiomer of [18F]THK-5117 (Figure 3d) to tau aggregates in AD brains, a new tracer called [18F]THK-5317 (Figure 3f, 6-((3-[18F]fluoro-2-hydroxy)propoxy)-2-(4-methylaminophenyl) quinoline) was developed, which proved to have superior pharmacokinetics in rodents. The gene discussed is MAPT; the disease is Alzheimer disease.