Amyloids are aggregates of proteins that become folded into a shape that allows many copies of that protein to stick together. In the human body, amyloids are usually unhealthy developments, as these previously healthy proteins most often lose their normal physiological function and form large fibrils. These fibrils disrupt the healthy function of nearby tissues and organs. Such amyloids have been known to arise from at least 18 different proteins and polypeptides, and have been associated with more than 20 human diseases, known as amyloidosis, and may play a role in some neurodegenerative disorders.