Abstract
Intracerebral hemorrhage (ICH) is caused by primary abnormality of cerebral blood vessels such as cerebral amyloid angiopathy (CAA) or secondary cerebrovascular changes by hypertension, coagulopathies, etc. Multiple genetic and environmental risk factors contribute to pathogenesis of ICH ; it has been reported that apolipoprotein (apoE) genotype is a major risk of lobar ICH, and that non-lobar ICH is mostly attributable to hypertension. CAA is classified to six types depending on 6 different amyloid proteins, i.e., amyloid β protein (Aβ), cystatin C, prion protein (PrP), ABri/ADan, transthyretin (TTR), and gelsolin. The most common type found in the elderly and Alzheimer's disease is sporadic Aβ type, in which ApoE E2 or E4 is reported to be risk of CAA or CAA-related ICH. Mutations of genes for six amyloid proteins or precursor proteins are associated with hereditary CAA; hereditary CAA of TTR and PrP type have been found in Japan.
