Efforts to protect dopaminergic neurons have shown the efficacy of AD4/NACA in decreasing damage in three experimental models of PD, the 6-OHDA-induced nigral lesion, the 1-methyl-4-phenyl-1,2,3,6,-tetrahydropyridine (MPTP), and a chronic intrajugular administration of rotenone in rats [56]. Here, PSEN2 is linked to Parkinson disease.