Chapter 5: Amyloidosis

Question 1

What is amyloidosis?

Answer 1

A condition associated with a number of disorder in which extracellular deposits of fibrillar proteins are responsible for tissue damaga and functional comrpomise.

Question 2

How do these abnormal fibrils arise?

Answer 2

They are produced by the aggregation of improperly folded proteins.

Question 3

What are the three most common forms of amyloid?

Answer 3

AL amyloid (made up of complete immunoglobulin light chains), AA amyloid (made up of proteins dervied from a lager SAA-precursor), β-amyloid (derived from APP).

Question 4

Normally,
intracellular misfolded proteins are degraded in proteasomes and extracellular protein aggregates are taken up
and degraded by macrophages. What goes wrong during amyloidosis?

Answer 4

These control mechanisms fail and fibrillar proteins accumulate outside of the cell.

Question 5

The proteins that form amyloid

fall into two general categories. What are these categories?

Answer 5

1. normal proteins that have a tendency to form fibrils, particularly when produced in increased amounts.
2. mutant proteins that are prone to misfolding and aggregation.

Question 6

By what is primary amyloidosis caused and what type of amyloid aggregates?

Answer 6

By clonal proliferation of plasma cells that synthesize abnormal IgG molecules, AL type amyloid aggregates.

Question 7

What are charasteristics of reactive systemic amyloidosis?

Answer 7

Is is composed of AA protein and it’s secondary to an associated inflammatory condition.