This rescue approach has already been demonstrated in two mice models of AD (PSEN1/PSEN2 conditional double knockout mice, without amyloid deposition, and APP/PS1/Tau triple transgenic mice, with amyloid deposition) [130] and in a rat model of PD (α‐synuclein knockdown) [158] but has yet to be tested in humans. The gene discussed is PSEN2; the disease is Parkinson disease.