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| ==Causes== | | ==Causes== |
| ===Systemic Amyloidosis===
| | Some causes of secondary amyloidosis are multiple myeloma (10-15%), rheumatoid arthritis (20-25%), tuberculosis (50%), or familial Mediterranean fever (26-40%) |
| ====Primary/Hereditary Amyloidosis====
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| These rare hereditary disorders are usually due to [[point mutations]] in precursor proteins, and are also usually [[autosomal dominant]]ly transmitted. The precursor proteins are:
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| * [[Transthyretin]]-the most commonly implicated protein.
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| * [[Lysozyme]]
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| * [[Apolipoprotein B]]
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| * [[Fibrinogen]]
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| * [[Apolipoprotein A1]]
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| * [[Gelsolin]]
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| ====Secondary Amyloidosis====
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| These are far more common than the primary amyloidoses.
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| * AL amyloidosis: ([[immunoglobulin light chains]] are the precursor protein, overproduced in [[multiple myeloma]]). This is sometimes, confusingly and erroneously, called 'primary amyloidosis'.
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| * AA amyloidosis: (the precursor protein is [[serum amyloid A protein]] (SAA), an [[acute-phase protein]] due to chronic [[inflammation]]). In contrast to AL amyloid, this has previously been termed 'secondary amyloidosis'. These occur with a wide variety of diseases associated with chronic inflammation, such as [[rheumatoid arthritis]], [[familial Mediterranean fever]] or chronic infection.
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| * Dialysis related amyloidosis: (the precursor protein is [[beta-2-microglobulin]] which is not removed with [[dialysis]], and thus accumulates in patients with [[end stage renal failure]] on dialysis).
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| ===Organ-Specific Amyloidosis===
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| 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. The associated proteins are indicated in parentheses.
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| '''Neurological Amyloid'''
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| * [[Alzheimer's disease]] ([[Amyloid beta|Aβ 39-43]])
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| * [[Parkinson's disease]] ([[alpha-synuclein]])
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| * [[Huntington's disease]] ([[huntingtin]])
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| * [[Transmissible spongiform encephalopathy|Transmissible spongiform encephalopathies]] caused by [[prion|prion protein]] (PrP) were sometimes classed as amyloidoses, as one of the four pathological features in diseased tissue is the presence of [[amyloid plaques]]. These diseases include
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| ** [[Creutzfeldt-Jakob disease]] (PrP in [[cerebrum]])
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| ** [[Kuru]] (diffuse PrP deposits in brain)
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| ** [[Fatal Familial Insomnia]] (PrP in [[thalamus]])
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| ** [[Bovine spongiform encephalopathy]] (PrP in [[cerebrum]] of cows)
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| '''Cardiovascular amyloid'''
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| * [[Cardiac amyloidosis]]
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| * See the chapter on [[CMR in Cardiac Amyloidosis]]
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| ** Senile cardiac amyloidosis-may cause [[heart failure]]
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| * [[Congophilic angiopathy]]
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| '''Other'''
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| * [[Amylin]] deposition can occur in the [[pancreas]] in some cases of [[Diabetes mellitus type 2|type 2 diabetes mellitus]]
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| == References == | | == References == |