Amyloidosis


Amyloidosis

MeshID = D000686
In 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 insoluble form, 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]

Diagnosis

Amyloid can be diagnosed on microscopic examination of affected tissue. Amyloid deposits can be identified histologically by Congo 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 under polarized light where amyloid deposits produce a distinctive 'apple green birefringence'. Further, specific tests are available to more precisely identify the amyloid protein. Biopsies are 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 pentraxin 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 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 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).

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 of Pittsburgh, Pennsylvania
*Louis J. Tullio, mayor of Erie, Pennsylvania
*Robert P. Casey, Governor of Pennsylvania
*Ed Guthman, Pulitzer Prize winner


=Additional

References

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] at Cleveland 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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