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ABetaA21G amyloidosis

Synonym(s) ABeta amyloidosis, Flemish type
ABetaA21G-related amyloidosis
HCHWA, Flemish type
Hereditary cerebral hemorrhage with amyloidosis, Flemish type
Prevalence <1 / 1 000 000
Inheritance Autosomal dominant
Age of onset Adult
  • E85.4+
  • I68.0*
MeSH -
MedDRA -


Disease definition

Hereditary cerebral hemorrhage with amyloidosis (HCHWA), Flemish type is a form of HCHWA (see this term) characterized by an age of onset of 45 years of age, progressive Alzheimer's disease-like dementia and lobar intracerebral hemorrhage in some patients.


It has been described in one Dutch and one British family.


HCHWA, Flemish type is due to a mutation in the APP gene on chromosome 21q21.2, encoding the beta-amyloid precursor protein. This mutation causes an increased accumulation of amyloid-beta protein in the walls of the arteries and capillaries of the meninges, cerebellar cortex and cerebral cortex, leading to the weakening and eventual rupture of these vessels.

Genetic counseling

Transmission is autosomal dominant.

Expert reviewer(s)

  • Dr Joost HAAN
  • Dr G.M. [Gisela] TERWINDT

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