The aggregation and cerebrovascular deposition of amyloid-β (Aβ) peptides, the products of sequential processing of the amyloid precursor protein (APP), in the walls of medium-sized and small brain vessels is the defining feature of CAA, a major cause of intracerebral hemorrhage (Charidimou et al., 2017; Greenberg et al., 2020). Here, APP is linked to intracerebral hemorrhage.