ABSTRACT
The amyloidoses are a collection of disorders arising from protein misfolding
and misassembly into insoluble b-rich sheets. Extracellular deposition of the resulting amyloid fibrils disrupts organ function, producing clinical disease.
Originally identified as carbohydrate by Virchow in 1854 (1), amyloid deposits
consist of linear arrays of subunit proteins complexed with glucosaminoglycans
and serum amyloid P (SAP) that stabilize the b-sheet conformation. Amyloid deposition occurs in systemic and organ-limited or localized forms. More than
20 proteins form amyloid fibrils (2). In systemic amyloidosis, the precursor
proteins forming amyloid fibrils dictate organ involvement and the resulting
clinical syndrome. Consequently, typing the amyloid allows disease classifica-
tion, prediction of disease progression, and basis for therapeutic intervention.