ITSN1 and Alzheimer disease: Two genes that are good candidates for neurodegenerative pathologies associated with DS are App, which is mutated in some forms of Alzheimer's disease [30] and of which the upregulation contributes substantially to degeneration of cholinergic neurons [31] and Itsn (Intersectin), which is involved in clathrin-mediated endocytosis [32].