PSEN1 and ADan amyloidosis: Although the familial cases caused by APP/PSEN mutations are classified as FAD and those caused by mutations in BRI2/ITM2b as Familial Danish or British dementias (FDD or FBD), recent evidence suggest that FBD and FDD share with FAD a pathogenic mechanism involving synaptic-toxic APP metabolites released during memory acquisition [11-16].