SLC6A3 and Parkinson disease: Collectively, these findings support that the αSyn/Syn III complex can constitute a druggable therapeutic target for PD, and that MPH therapeutic efficacy in patients in advanced stages of disease with freezing of gait [18,19], which should not respond to MPH treatment in light of their marked reduction in striatal DAT [20], may be ascribed to the ability of this drug to stimulate the functional αSyn/Syn III interaction.