In patients with 4R-tauopathies, tau-PET in basal ganglia and midbrain regions is negatively associated with striatal DAT availability, whereas those with α-synucleinopathies like MSA showed no such relationship, indicating that tau burden in brain regions involved in dopaminergic pathways is associated with aggravated dopaminergic dysfunction in tauopathies that might involve various functions [230]. Here, SLC6A3 is linked to multiple system atrophy.