Dopamine transporter imaging (DAT-SPECT or DAT-PET) can support the clinical diagnosis of PD (Liu et al., 2018; Mirpour et al., 2018; Suwijn et al., 2015), yet only two of the 16 included studies performed DAT-SPECT and PD patients enrolled in future studies should have this scan when research costs are permitted. Here, SLC6A3 is linked to Parkinson disease.