Amyloid is

Ref Robbins 9/e p256 Amyloidosis is a condition associated with a number of inherited and inflammatory disorders in which extracel- lular deposits of fibrillar proteins are responsible for tissue damage and functional compromise. These abnormal fibrils are produced by the aggregation of misfolded pro- teins (which are soluble in their normal folded configura- tion) or protein fragments. The fibrillar deposits bind a wide variety of proteoglycans and glycosaminoglycans, including heparan sulfate and dermatan sulfate, and plasma proteins, notably serum amyloid P component (SAP). The presence of abundant charged sugar groups in these adsorbed proteins gives the deposits staining charac- teristics that were thought to resemble starch (amylose). Therefore, the deposits were called "amyloid," a name that is firmly entrenched despite the realization that the depos- its are unrelated to starch.