MeshID = D000686
medicine, amyloidosis refers to a variety of conditions in which amyloid proteins are abnormally deposited in organs and/or tissues, causing disease. A protein is amyloid if, due to an alteration in its secondary structure, it takes on a particular insolubleform, called the beta-pleated sheet.cite web |url=https://www-s.med.uiuc.edu/m2/pathology/PathAtlasf/CVAtlas020.html |title=Atlas of Pathology |format= |work= |accessdate=]
The term "amyloidosis" refers to a histological finding occurring in several different disease processes that have little in common with each other, and without additional information, the finding is of limited clinical use.cite journal |author=Gertz MA |title=The classification and typing of amyloid deposits |journal=Am. J. Clin. Pathol. |volume=121 |issue=6 |pages=787–9 |year=2004 |month=June |pmid=15198347 |doi=10.1309/TR4L-GLVR-JKAM-V5QT |url=http://ajcp.metapress.com/openurl.asp?genre=article&issn=0002-9173&volume=121&issue=6&spage=787]
Amyloid can be diagnosed on microscopic examination of affected tissue. Amyloid deposits can be identified
histologicallyby Congo redstainingcite journal |author=Satoskar AA, Burdge K, Cowden DJ, Nadasdy GM, Hebert LA, Nadasdy T |title=Typing of amyloidosis in renal biopsies: diagnostic pitfalls |journal=Arch. Pathol. Lab. Med. |volume=131 |issue=6 |pages=917–22 |year=2007 |month=June |pmid=17550319 |doi= |url=http://journals.allenpress.com/jrnlserv/?request=get-abstract&issn=0003-9985&volume=131&page=917] and viewing under polarized lightwhere amyloid deposits produce a distinctive 'apple green birefringence'. Further, specific tests are available to more precisely identify the amyloid protein. Biopsiesare taken from affected organs (for example, the kidney), or often in the case of systemic amyloid, from the rectum, gingiva, or omentum(anterior abdominal adipose tissue). [Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; & Mitchell, Richard N. (2007). "Robbins Basic Pathology" (8th ed.). Saunders Elsevier. p.171 ISBN 978-1-4160-2973-1]
In addition, all amyloid deposits contain
serum amyloid P component(SAP),cite journal |author=Togashi S, Lim SK, Kawano H, "et al" |title=Serum amyloid P component enhances induction of murine amyloidosis |journal=Lab. Invest. |volume=77 |issue=5 |pages=525–31 |year=1997 |month=November |pmid=9389795 |doi= |url=] a circulating protein of the pentraxinfamily. RadionuclideSAP scans have been developed which can anatomically localize amyloid deposits in patients.
Bleeding under the skin, called
amyloid purpura, is seen in a minority of patients with amyloidosis.cite journal |author=Eder L, Bitterman H |title=Image in clinical medicine. Amyloid purpura |journal=N. Engl. J. Med. |volume=356 |issue=23 |pages=2406 |year=2007 |month=June |pmid=17554122 |doi=10.1056/NEJMicm061510 |url=http://content.nejm.org/cgi/pmidlookup?view=short&pmid=17554122]
Classification of amyloid
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
mutationsin the precursor protein. Other forms are due to different diseases causing overabundant or abnormal protein production-such as with over production of immunoglobulin light chainsin multiple myeloma(termed AL amyloid), or with continuous overproduction of acute phase proteins in chronic inflammation(which can lead to AA amyloid).
There are at least 15 biologically distinct forms of amyloid, some more clinically significant than others. Following is a brief description of the more common types of amyloid:
In almost all of the organ-specific pathologies, there is significant debate as to whether the amyloid plaques are the causal agent of the disease or instead a downstream consequence of a common
Famous people who have been affected by amyloidosis
Robert Jordan, author of the " The Wheel of Time" series
David Lange, Prime Minister of New Zealand
Richard Caliguiri, mayor of Pittsburgh, Pennsylvania
Louis J. Tullio, mayor of Erie, Pennsylvania
Robert P. Casey, Governor of Pennsylvania
Ed Guthman, PulitzerPrize winner
* [http://www.mayoclinic.org/amyloidosis/ Overview] at
* [http://www.clevelandclinic.org/health/health-info/docs/0600/0658.asp?index=4775 Overview] at
* [http://www.bu.edu/amyloid] Boston University Amyloid Treatment and Research Program
* [http://www.amyloidosisaustralia.org www.amyloidosisaustralia.org] Information, support and advice to anyone with Amyloidosis
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