Finally, multiple mutations in the APP gene that increase misfolding and aggregation can predispose individuals to develop hereditary cerebral hemorrhage with amyloidosis (HCHWA), a heritable form of CAA that is associated with early and severe disease onset (Luyendijk et al., 1988; Van Broeckhoven et al., 1990; van Nostrand et al., 1992, 2001; Davis et al., 2004). The gene discussed is APP; the disease is cerebral amyloid angiopathy.