Amyloidosis is an abnormal accumulation of amyloid proteins in the body organs or tissues. Amyloids are insoluble fibrous protein aggregates sharing specific structural traits. Amyloidosis may play a role in various degenerative diseases. Although deposition patterns of amyloid proteins vary between patients, they are almost always composed of just one amyloidogenic protein. Deposition can be systemic, affecting many different organ systems, or organ-specific. Many amyloidoses are inherited, due to mutations in the precursor protein.