Amyloidosis

In medicine, amyloid refers to a particular insoluble form that many different proteins can take, due to an alteration in their secondary structure. This characteristic alteration in the protein shape is called the beta-pleated sheet. Amyloidosis refers to a variety of conditions in which amyloid proteins are abnormally deposited in organs and/or tissues, causing disease.

Approximately 25 different proteins are known that can form amyloid in humans, most of them are constituents of the plasma.

Different amyloidoses can be systemic-affecting many different organ systems, or organ specific. Some are inherited, due to mutations in the precursor protein. Other, secondary forms are due to different diseases causing overabundant or abnormal protein production-such as with over production of immunoglobulin light chains in multiple myeloma (termed AL amyloid), or with continuous overproduction of acute phase proteins in chronic inflammation (which can lead to AA amyloid).