What Are Amyloid Diseases? in What Respects Do Neurodegenerative Amyloid

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The Answer is Amyloid protein is the term used to describe a broad family of proteins that have a high content of

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-sheets that make them prone to aggregation. Prions are a well-known subclass of amyloid proteins but in addition there are many other examples. Amyloid diseases are disorders in which amyloid proteins are implicated. The aggregation of amyloid proteins can occur outside of cells (such as in the case of prion proteins and

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-amyloid), within nuclei (huntingtin), or within the cytoplasm (SOD1; Tau; and synuclein).
Some common amyloid diseases are not associated with neurodegeneration, such as type 2 diabetes (aggregates of serum amyloid A protein are found in the pancreatic islets of Langerhans). However, neurodegeneration is the most striking clinical characteristic of many amyloid diseases.
Alzheimer disease, Parkison disease, amyotrophic lateral sclerosis, and frontotemporal disease, resemble prion protein diseases in many ways and are sometimes classified as prionoid diseases. In these diseases direct involvement of the aggregated proteins in disease is supported from familial forms of these disorders in which mutations in the relevant gene promote the formation of amyloid protein.
There is no evidence from animal studies that the aggregated proteins in prionoid disorders are infectious like prion proteins. But there is quite strong evidence that the pathogenesis resembles prion protein disease in two respects. First, like prion proteins, misfolded amyloid proteins in these disorders can induce the formation of the amyloid state in the normal proteins so that they aggregate. Secondly, for several of the disorders there is strong evidence for cell-to-cell spreading of the disorder.

What Are Amyloid Diseases? in What Respects Do Neurodegenerative Amyloid

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