However, when delivered extracellularly into the striata of the 6-hydroxydopamine (6-OHDA)-treated rats, serving as a model of the dopamine deficiency seen in Parkinson’s disease (PD) patients, MANF and CDNF behave as bona fide NTFs, protecting dopaminergic neurons from degeneration. The gene discussed is CDNF; the disease is Parkinson disease.