PMC

Schematic representation of Aβ proteolysis by major Aβ-degrading enzymes. Thick arrows indicate major cleavage sites

Mutations in the APP gene and their relationship to the amino acid sequence of the Aβ peptide. The Dutch and London mutations of the APP gene, shown in red, were the first described within and outside the sequence of the Aβ peptide, respectively

a A Congo red-positive cortical arteriole in sporadic Aβ-CAA showing (b) characteristic apple green birefringence in polarised light. c Deposition of Aβ peptide in the vascular wall is extensive and double barrelling with ‘vessel-within-vessel’ appearance is also seen. The bar on a represents 30 μm on all images

a–c Marked activated microglial reaction in relation to amyloid laden blood vessels in familial British dementia (confocal microscopy, a Thioflavin S, b Cr3/43, c combined image). d–f The C1q component of the classical complement cascade co-localises with ADan deposition in cerebrovascular amyloid in familial Danish dementia (confocal microscopy, a ADan, b C1q, c combined image). The bar on a represents 30 μm on a–c and 60 μm on d–f

Different amyloid peptides in hereditary CAAs. a Deposition of Aβ peptide in blood vessels and diffuse parenchymal plaques in cerebral cortex in HCHWA-D. b Accumulation of mutated cystatin C in leptomeningeal and cerebral cortical blood vessels in HCHWA-I. c Widespread deposition of ABri in FBD d and ADan in FDD is characteristic (c and d: cerebellar cortex). e: ATTR deposition is abundant in the leptomeninges and leptomeningeal blood vessels in the Hungarian form of meningovascular amyloidosis (lumbar cord). f PrP^Sc deposition in blood vessels and parenchyma is a characteristic morphological feature of human prion disease with the novel Y163STOP mutation of the PRNP gene (cerebellum). g Deposition of AGel in skin blood vessels in familial amyloidosis of the Finnish type. The bar on b repsents 60 μm on a, 30 μm on b–e and g, 15 μm on f