Different types of amyloidosis are named according to the proteins which form the amyloid fibrils. All have the initial “A” denoting amyloidosis and letter(s) identifying the particular precursor protein which forms amyloid fibrils within the amyloid deposits. For example:
AL amyloidosis: Light chains (fragments of monoclonal immunoglobulins (antibodies)) are the amyloid precursor protein. This is the most common form of amyloidosis and was formerly known as primary amyloidosis.
ATTR amyloidosis: Transthyretin (TTR), a normal blood protein, present in everybody, is the amyloid precursor protein. ATTR amyloidosis may be inherited (hereditary ATTR amyloidosis) or non-inherited (wild type ATTR amyloidosis, also known as ATTRwt).
AA amyloidosis: Serum amyloid A protein (SAA), a blood protein whose levels rise when there is prolonged inflammation, is the amyloid precursor protein. This was formerly known as secondary amyloidosis.
Aβ2M amyloidosis: Beta 2 Microglobulin (β2M) is the amyloid precursor protein.
AFib amyloidosis: Fibrinogen is the amyloid precursor protein.
A wide variety of other proteins can form amyloid in the various rare, hereditary types of amyloidosis.
Amyloidosis may be either systemic or local:
Amyloidosis may also be either acquired or hereditary: