In AD, the amyloid plaques are primarily composed of amyloid-β (Aβ) peptides, which derive from the proteolytic processing of Amyloid-β Precursor protein (APP), whereas in FDD and FBD, the plaques are composed of the cleavage products of the mutant BRI2 proteins, the ADan peptide, or the ABri peptide, respectively (Garringer et al, 2010). The gene discussed is APP; the disease is Alzheimer disease.