RT Book, Section A1 Palmer, Shanique R. A1 Mueller, Paul S. A1 Gertz, Morie A2 Imboden, John B. A2 Hellmann, David B. A2 Stone, John H. SR Print(0) ID 57275085 T1 Chapter 57. Amyloidosis T2 CURRENT Diagnosis & Treatment: Rheumatology, 3e YR 2013 FD 2013 PB The McGraw-Hill Companies PP New York, NY SN 978-0-07-163805-0 LK accessmedicine.mhmedical.com/content.aspx?aid=57275085 RD 2024/04/23 AB Amyloidosis is not a single disease but a heterogeneous group of diseases that share in common the extracellular deposition of insoluble fibrillar proteins in tissues and organs. These protein deposits derive from diverse and unrelated serum precursor proteins, yet have similar beta-pleated sheet structural conformations. Furthermore, all forms of amyloid display apple-green birefringence when stained with the cotton-wool dye Congo red and viewed under polarized light. Indeed, this observation (via tissue biopsy) remains the primary means of establishing the diagnosis of amyloidosis. Accumulation of amyloid deposits leads to tissue and organ dysfunction, which in turn causes clinical symptoms and, for some patients, death.