Amyloid beta
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Amyloid beta (Aβ or Abeta) is a protein fragment of 39-43 amino acids that is the main constituent of amyloid plaques in the brains of Alzheimer's disease patients. Similar plaques appear in some variants of Lewy body dementia. Aβ also forms aggregates coating cerebral blood vessels in cerebral amyloid angiopathy.
Aβ is formed after sequential cleavage of the amyloid precursor protein (APP) by the β- and γ-secretases. APP is a transmembrane glycoprotein. Autosomal-dominant mutations in APP cause hereditary early-onset Alzheimer's disease, likely as a result of altered proteolytic processing. Increases in either total Aβ levels or the relative concentration of the 42-amino acid form have been implicated in the pathogenesis of both familial and sporadic Alzheimer's disease.
External link
- OMIM [104300]
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