SLC6A4 and Parkinson disease: Radiopharmaceuticals that bind to the serotonin transporter (SERT), such as [11C]-(3-amino-4-(2-dimethylamino-methyl-phenyl-sulfonyl)-Benzonitrile) ([11C]-DASB), or to Acetylcholinesterase (AChE) enzyme as [11C]-methyl-4-piperidyl acetate ([11C]-MP4A), allow to map brain SERT in patients with different degrees of PD severity, or cholinergic denervation associated with progressive cognitive decline and loss of odor discrimination (Politis et al., 2010).