Key word included are: ("Alzheimer's disease" OR dementia) AND ("viral" OR "non-viral vectors" OR "gene therapy" OR "gene transfer" OR "viral vector" OR "AAV" OR "lentivirus" OR "CRISPR") AND ("Neurotrophic factors" OR "NTF" OR "NGF" OR "nerve growth factor" OR "BDNF" OR "brain-derived neurotrophic factor"). This evidence concerns the gene NGF and dementia.