SLC6A3 and Parkinson disease: The use of dopamine transporter (DAT) ligands, such as 123I-FP-Cit (N-ω-fluoropropyl-2-β-carbomethoxy-3β-(4-[123I]iodophenyl)nortropane), 123I Ioflupane, (GE Healthcare B.V., Eindhoven, The Netherlands), to examine the integrity of the nigrostriatal dopamine function with imaging techniques, such as single photon emission computed tomography (SPECT), have shown high sensitivity in idiopathic parkinsonian diseases [5, 6] but a low discriminative power in separating PD from APD [7].