Amyloid-β is a key player in pathomechanisms of various neurogenerative diseases, such as Alzheimer’s disease, frontotemporal dementia, cerebral amyloid angiopathy, and cerebral amyloidosis, through multiple pathways [193,195]; however, the detailed roles of 5-HT7 in pathomechanisms of neurodegenerative disease associated with amyloid-β remain to be clarified [196,197]. This evidence concerns the gene HTR7 and early-onset autosomal dominant Alzheimer disease.