Amyloidosis

Amyloid fibrils are protein polymers comprising identical monomer units (homopolymers). 

Functional amyloids play a beneficial role in a variety of physiologic processes (eg, long-term memory formation, gradual release of stored peptide hormones). 

Amyloidosis results from the accumulation of pathogenic amyloids—most of which are aggregates of misfolded proteins—in a variety of tissues. ^[1]

^{https://emedicine.medscape.com/article/335414-overview}

https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/amyloidosis/amyloidosis