Neuroimaging showed small to large hematomas, subarachnoid bleeding, scars with hemosiderin deposits, small infarcts, and leukoaraiosis. Aβ immunoreactivity was detected in the walls of leptomeningeal and parenchymal vessels and in the neuropil. This disease is distinguished from Alzheimer's disease with CAA by the absence of neurofibrillary changes and neuritic plaques
(Tagliavini et al., 1999
; Bugiani et al., 2010
CAA caused by the Italian or Dutch Aβ variants is uniquely characterized by deposition of Aβ in the smooth muscle cells surrounding the cerebral vasculature
as compared to the typical Aβ pathology in sporadic AD, which is found mostly in brain parenchymaThe absence of neuritic plaques and tangles made it possible to distinguish the disease from familial AD with CAA and to call it hereditary cerebral hemorrhage with amyloidosis (HCHWA). Biological Effect
It is possible that this variant affects the conformation of Aβ peptides changing their rate of fibrillization. Indeed, a variant in this same position and associated with a similar phenotype, E693Q
, accelerates polymerization into protofibrils and fibrils.