Contrarily, dopamine transporter (DaT) imaging, such as 123I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)-nortropane single-photon emission computerized tomography (123I-FP-CIT SPECT), can provide information regarding nigrostriatal function based on quantified DaT uptake in the striatum; thus, it can diagnose Parkinsonism and monitor the disease [12, 13]. The gene discussed is SLC6A3; the disease is Parkinsonism.