3xTg-AD: Triple Transgenic Mouse Model of Alzheimer’s Disease, AAV: Adeno-Associated Virus, AAVT42: Adeno-Associated Virus serotype T42, AD: Alzheimer’s Disease, Aβ: Amyloid Beta, ASO: α-Synuclein Overexpression, BDNF: Brain-Derived Neurotrophic Factor, CBP: CREB-Binding Protein, CREB: cAMP Response Element-Binding Protein, GDNF: Glial cell line-Derived Neurotrophic Factor, MC65: Human neuroblastoma cell line (expressing APP-C99 upon tetracycline withdrawal), NF-α1: Neurotrophic Factor Alpha 1, NMDA: N-Methyl-D-Aspartate, NSC: Neural Stem Cell, SeV: Sendai Virus. This evidence concerns the gene GDNF and early-onset autosomal dominant Alzheimer disease.