What is the role of genetics in the etiology of cerebral amyloid angiopathy (CAA)?

Updated: Dec 19, 2018
  • Author: Ravi S Menon, MD; Chief Editor: Helmi L Lutsep, MD  more...
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Hereditary cerebral hemorrhage with amyloidosis-Dutch type is an autosomal-dominant disorder with complete penetrance. Among affected individuals, 87% have ICH and 13% have infarcts (deep).The age of onset of ICH is in the sixth decade (mean, 55 y). Some patients develop dementia without ICH.

Amyloid deposits are found in cortical and leptomeningeal vessels; parenchymal neurofibrillary tangles are not seen. Deposited amyloid protein in these patients is identical to the amyloid protein seen in sporadic cases, and the likely genetic defect is in the amyloid protein precursor protein (APP) gene on chromosome 21.

Icelandic type

Hereditary cerebral hemorrhage with amyloidosis-Icelandic type is also autosomal dominant. Patients present with their first episode of ICH in the third or fourth decade, with some patients as young as age 15 years dying from ICH. One case report identified a family with late-onset dementia with and without ICH.

The amyloid angiopathy is more widely distributed in this type than in other types, involving arteries in the cerebrum, cerebellum, and brainstem. The amyloid protein is a mutant of the cysteine protease inhibitor cystatin C.

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