Abnormal arrangements of protein fibrils – fine fibres – are known as amyloid structures. Unlike other fibrous proteins, these cease to have a useful role and are associated with diseases such as Alzheimer's and type II diabetes.
Recent research has pointed to (-)-Epigallocatechin 3-Gallate (EGCG), incidentally an ingredient of green tea, as a possible drug candidate for inhibition of fibril formation or even promoting disassembly.
Further details: Formation of fibrils in Alzheimer's cut by mystery product