SLC6A3 and Parkinson disease: Since non-motor symptoms have proven to be accompanied by low mIBG uptake [41], mIBG-scintigraphy can be a useful marker during the DAT-SPECT negative period to identify premotor PD [42].This multicenter study confirmed the superior diagnostic accuracy of the mIBG exam compared to DAT-SPECT in diagnosing PD in de novo patients, probably related to the fact that damage to the presynaptic postganglionic sympathetic fibers occurs earlier than damage to the presynaptic terminals of dopaminergic neurons.