Postmortem studies have shown an association between PD and striatal DAT concentration.37,38 Evaluation of DAT in human postmortem tissue has demonstrated good correlation of in vitro tracers such as [125I] altropane and DAT reduction in PD.39 DAT provides a good site for monitoring the integrity of the presynaptic dopaminergic systems that are most affected in PD. Here, SLC6A3 is linked to Parkinson disease.