Introduction

The term cerebral amyloid angiopathy (CAA) (synonymous with cerebral congophilic angiopathy and cerebrovascular amyloidosis) describes and defines a pathologic condition whereby the media of small arteries (arterioles), veins (venules) and adventitial component of capillaries is replaced by one of several fibrillar proteins that have a betapleated sheet configuration (Vinters, 1987). Whereas the older literature differentiates between primarily capillary and arteriolar amyloid deposition, modern conceptualization of CAA defines the microangiopathy based upon the biochemical composition of the primary molecule that constitutes the fibrillar amyloid deposits (Coria and Rubio, 1996). Thus, several forms of CAA are recognized:

1. CAA associated with Alzheimer disease/senile dementia of Alzheimer type (AD/SDAT), Down's syndrome (DS) and brain aging – biochemically composed of beta/A4 protein – is by far the most common form of CAA worldwide.

2. CAA in Icelandic patients who suffer from a hereditary form of cerebral hemorrhage – best described by the terms hereditary cerebral hemorrhage with amyloidosis, Icelandic (HCHWA-I); or, since the amyloid protein is a variant of gamma-trace/cystatin C, hereditary cystatin C amyloid angiopathy (HCCAA) (Ólafsson et al., 1996).

3. CAA in Dutch patients who also experience frequent brain hemorrhage on a hereditary basis – by analogy to the Icelandic condition, referred to as HCHWA-D (Bornebroek et al., 1996; Maat-Schieman et al., 1996).

4. […]