Amyloidosis: Wikis

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Amyloidosis
Classification and external resources

Micrograph showing amyloid deposition (red fluffy material) in the heart (cardiac amyloidosis). Congo red stain.
ICD-10 E85.
ICD-9 277.3
DiseasesDB 633
eMedicine med/3377 med/3888
MeSH D000686

In medicine, amyloidosis refers to a variety of conditions in which amyloid proteins are abnormally deposited in organs and/or tissues. A protein is described as being amyloid if, due to an alteration in its secondary structure, it takes on a particular aggregated insoluble form similar to the beta-pleated sheet.[1] Symptoms vary widely depending upon the site of amyloid deposition. Amyloidosis may be inherited or acquired.[2]

Contents

Classification

Amyloidosis may be divided into the following types:[3]

Diagnosis

Amyloid can be diagnosed on microscopic examination of affected tissue. Extracellular amyloid deposits can be identified histologically by Congo red staining[4] and viewing under polarized light where amyloid deposits produce a distinctive apple green birefringence. Other more 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).[5]

In addition, all amyloid deposits contain serum amyloid P component (SAP),[6] 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.[7] This type of lesion may be pronounced in the periorbital area.

Histology: amorphous; eosinophilic; extracellular material; extracted amyloid has pentagonal structures, the P component.

Classification of amyloid

The modern classification of amyloid disease tends to use an abbreviation of the protein that makes up the majority of deposits, prefixed with the letter A. For example amyloidosis caused by transthyretin is termed "ATTR". Deposition patterns vary between patients but 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. 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).

Out of the approximately 60 amyloid proteins that have been identified so far,[8] at least 36 have been associated in some way with a human disease.[9]

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Standard classification

Following is a brief description of the more common types of amyloid:

Abb. Amyloid type Description
AL amyloid light chain Contains immunoglobulin light-chains (λ,κ) derived from plasma cells
AA amyloid associated Non-immunoglobulin protein made in the liver (terminal)
β amyloid Found in Alzheimer disease brain lesions
ATTR Transthyretin A mutant form of a normal serum protein that is deposited in the genetically determined familial amyloid polyneuropathies. TTR is also deposited in the heart in senile systemic amyloidosis.[10]
2M β2 microglobulin Not to be confused with , β2m is a normal serum protein, part of major histocompatibility complex (MHC) Class 1 molecules. Can occur in long term haemodialysis.
IAPP Amylin Found in the pancreas of patients with type 2 diabetes
PrP Prion protein In Prion diseases, misfolded prion proteins deposit in tissues and resemble amyloid proteins.

OMIM includes the following:

OMIM Gene Name Number
176300 TTR Senile systemic amyloidosis (type 1)
105120 GSN Finnish type amyloidosis (type 5)
105150 CST3 Cerebral amyloid angiopathy, Icelandic type (type 6)
105210 TTR Leptomeningeal amyloidosis (type 7)
105200 APOA1, FGA, LYZ Familial visceral amyloidosis (type 8)
105250 OSMR Primary cutaneous amyloidosis (type 9)
176500 ITM2B Cerebral amyloid angiopathy, British type -
609065, 605714 APP Dutch type / Italian type / Iowa type -

Alternative classifications

An older, clinical, method of classification refers to the amyloidoses as systemic or localised

  • Systemic amyloidoses are those which affect more than one body organ or system. Examples are: AL, AA and Aβ2m.[11]

Another classification is primary or secondary.

  • Primary amyloidoses arise from a disease with disordered immune cell function such as multiple myeloma and other immunocyte dyscrasias.
  • Secondary (reactive) amyloidoses are those occurring as a complication of some other chronic inflammatory or tissue destructive disease. Examples are reactive systemic amyloidosis.[11]

Famous people who have been affected by amyloidosis

Additional images

References

  1. ^ "Atlas of Pathology". https://www-s.med.uiuc.edu/m2/pathology/PathAtlasf/CVAtlas020.html.  
  2. ^ Pavelka, Margit; Roth, Jürgen. Functional Ultrastructure: An Atlas of Tissue Biology and Pathology. Springer. pp. 258. ISBN 3-211-83564-4.  
  3. ^ James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology. (10th ed.). Saunders. ISBN 0721629210.
  4. ^ Satoskar AA, Burdge K, Cowden DJ, Nadasdy GM, Hebert LA, Nadasdy T (June 2007). "Typing of amyloidosis in renal biopsies: diagnostic pitfalls". Arch. Pathol. Lab. Med. 131 (6): 917–22. PMID 17550319. http://journals.allenpress.com/jrnlserv/?request=get-abstract&issn=0003-9985&volume=131&page=917.  
  5. ^ 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
  6. ^ Togashi S, Lim SK, Kawano H, et al. (November 1997). "Serum amyloid P component enhances induction of murine amyloidosis". Lab. Invest. 77 (5): 525–31. PMID 9389795.  
  7. ^ Eder L, Bitterman H (June 2007). "Image in clinical medicine. Amyloid purpura". N. Engl. J. Med. 356 (23): 2406. doi:10.1056/NEJMicm061510. PMID 17554122. http://content.nejm.org/cgi/pmidlookup?view=short&pmid=17554122.  
  8. ^ Mok KH, Pettersson J, Orrenius S, Svanborg C (March 2007). "HAMLET, protein folding, and tumor cell death". Biochem. Biophys. Res. Commun. 354 (1): 1–7. doi:10.1016/j.bbrc.2006.12.167. PMID 17223074.  
  9. ^ Pettersson-Kastberg J, Aits S, Gustafsson L, et al. (November 2008). "Can misfolded proteins be beneficial? The HAMLET case". Ann. Med. 41: 1–15. doi:10.1080/07853890802502614. PMID 18985467.  
  10. ^ Hassan W, Al-Sergani H, Mourad W, Tabbaa R (2005). "Amyloid heart disease. New frontiers and insights in pathophysiology, diagnosis, and management". Tex Heart Inst J 32 (2): 178–84. PMID 16107109.  
  11. ^ a b c Table 5-12 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson (2007). Robbins Basic Pathology. Philadelphia: Saunders. ISBN 1-4160-2973-7.   8th edition.

External links

Review Amyloidosis] Covering structure, mechanisms of action and kinetics of amyloid fibrils.


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