- Amyloidosis
MeshID = D000686
Inmedicine , amyloidosis refers to a variety of conditions in whichamyloid protein s are abnormally deposited in organs and/or tissues, causing disease. A protein is amyloid if, due to an alteration in itssecondary structure , it takes on a particularinsoluble form, called thebeta-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]
Diagnosis
Amyloid can be diagnosed on microscopic examination of affected tissue. Amyloid deposits can be identified
histologically byCongo red stainingcite 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 underpolarized light where amyloid deposits produce a distinctive 'apple greenbirefringence '. Further, specific tests are available to more precisely identify the amyloid protein.Biopsies are taken from affected organs (for example, thekidney ), or often in the case of systemic amyloid, from therectum ,gingiva , oromentum (anterior abdominaladipose 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 thepentraxin family.Radionuclide SAP 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
human s. 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 forms are due to different diseases causing overabundant or abnormal protein production-such as with over production ofimmunoglobulin light chains inmultiple myeloma (termed AL amyloid), or with continuous overproduction ofacute phase protein s inchronic 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:
Organ-specific amyloidosis
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
idiopathic agent.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 ofPittsburgh, Pennsylvania
*Louis J. Tullio , mayor ofErie, Pennsylvania
*Robert P. Casey , Governor ofPennsylvania
*Ed Guthman ,Pulitzer Prize winner
=AdditionalReferences
External links
* [http://www.mayoclinic.org/amyloidosis/ Overview] at
Mayo Clinic
* [http://www.clevelandclinic.org/health/health-info/docs/0600/0658.asp?index=4775 Overview] atCleveland Clinic
* [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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