In fact, as of now, about 300 mutations in PSEN1 and 58 mutations in PSEN2 have been described (https://www.alzforum.org/mutations), the majority of which are dominant, mostly missense, and have been associated with the inherited forms of the disease (familial Alzheimer’s disease (FAD)) [4,5]. This evidence concerns the gene PSEN2 and familial Alzheimer disease.