F-dopa and DAT studies have traditionally been used to evaluate the disease severity of PD by assessing the integrity of dopaminergic terminals (Morrish et al., 1996, Puñal-Riobóo et al., 2009, Heiss and Hilker, 2004, Rahmim et al., 2016). This evidence concerns the gene SLC6A3 and Parkinson disease.