Skip to Main Content


Amyloidosis is the term for diseases caused by the extracellular deposition of insoluble polymeric protein fibrils in tissues and organs. These diseases are a subset of a growing group of disorders attributed to misfolding of proteins. Among these are Alzheimer's disease and other neurodegenerative diseases, transmissible prion diseases, and genetic diseases caused by mutations that lead to misfolding, aggregation, and protein loss of function, such as certain of the cystic fibrosis mutations. Amyloid fibrils share a common β-pleated sheet structural conformation that confers unique staining properties. The term amyloid was coined by the pathologist Rudolf Virchow around 1854, who thought such deposits were cellulose-like under the microscope.


Amyloid diseases are defined by the biochemical nature of the protein in the fibril deposits and are classified according to whether they are systemic or localized, acquired or inherited, and by their clinical patterns (Table 112-1). The accepted nomenclature is AX, where A indicates amyloidosis and X represents the protein in the fibril. AL is amyloid composed of immunoglobulin light chains (LCs), and has been called primary systemic amyloidosis; it arises from a clonal B cell disorder and may be associated with myeloma or lymphoma. AF groups the familial amyloidoses, most commonly due to mutations in transthyretin, the transport protein for thyroid hormone and retinol-binding protein. AA amyloid is composed of the acute-phase reactant serum amyloid A protein and occurs in the setting of chronic inflammatory or infectious diseases and has been termed secondary amyloidosis. Aβ2M is amyloid composed of β2-microglobulin and occurs in individuals with end-stage renal disease (ESRD) of long duration. Aβ is the most common form of localized amyloidosis. Aβ is deposited in the brain in Alzheimer's disease and is derived from abnormal proteolytic processing of the amyloid precursor protein (APP).

Table Graphic Jump Location
Table 112-1 Amyloid Fibril Proteins and Their Clinical Syndromes

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.


About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessMedicine Full Site: One-Year Subscription

Connect to the full suite of AccessMedicine content and resources including more than 250 examination and procedural videos, patient safety modules, an extensive drug database, Q&A, Case Files, and more.

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessMedicine

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.