Astrocyte<unk>  has been identified as occurring either sporadically (generally in elderly populations) or in familial forms such as Flemish, Iowa, and Dutch types. In all cases, it is defined by the deposition of<unk>  beta (Aβ) in the leptomeningal and cerebral vessel walls.<unk>  occurring in the Flemish type has been observed to be linked to large dense-core plaques observed in this pedigree. The reason for increased deposition of Aβ in sporadic<unk>  is still unclear with both increased production of the peptide and abnormal clearance having been proposed as potential causes. Under normal physiology Aβ is cleared from the brain by four pathways: (1) endocytosis by astrocytes and microglial cells, (2) enzymatic degradation by neprilysin or insulysin (3) cleared by way of the blood brain barrier or (4) drained along periarterial spaces. Abnormalities in each of these identified clearance pathways have been linked to<unk> . In familial forms of<unk> , the cause of Aβ build up is likely due to increased production rather than poor clearance. Mutations in the<unk>  precursor protein (APP), Presenilin (PS) 1 and PS2 genes can result in increased rates of cleavage of the APP into Aβ. An immune mechanism has also been proposed. apolipoprotein E (APOE) ε2 and ε4 are associated with increased risk of getting cerebral<unk>  antipathy. The use of antiplatelet and anticoagulant therapy increases the risk of getting intracerebral haemorrhage in<unk> . Types Several familial variants exist. The condition is usually associated with<unk>  beta. However, there are types involving other<unk>  peptides: * the "Icelandic type" is associated with Cystatin C<unk>  (ACys). * the "British type" and "Danish type" are associated with British<unk>  (ABri) and Danish<unk>  (ADan) respectively. Both peptides are linked to mutations in ITM2B. * Familial<unk> osis-Finnish type is associated with gelsolin<unk>  (AGel). Research is currently being conducted to determine if there is a link between<unk>  and ingestion of excessive quantities of aluminium.
Cerebral amyloid angiopathy
Cerebral atherosclerosis
Cerebral vasculitis
Hypertensive leukoencephalopathy
Diabetic angiopathy
Infectious intracranial aneurysm
Cerebral arteriovenous malformation
Moyamoya disease