Amyloid-a

Amyloid A, abbreviated as "AA" (AA=amyloid associated) belongs to a group of polymorphic fibre proteins which, in acquired or hereditary amyloidosis, are deposited as insoluble, fibrillar aggregates in organs, vessels and nerves. Amyloidosis is caused by a disturbance in protein folding.

The precursor protein for amyloid A is the serum amyloid A protein (SAA), an acute phase protein. The SAA protein is found in the amyloid after long-term, chronic inflammation (acquired amyloidosis) or in rare hereditary diseases such as familial Mediterranean fever and Muckle-Wells syndrome (AA amyloidosis, urticaria and hearing loss).