Abstract
Systemic amyloidosis refers to a group of diseases that are caused by the misfolding of proteins and their deposition as amyloid fibrils in various organs. Here we present an overview of the progress made in the understanding of the biochemical and structural characteristics of the pathogenic agents of these diseases, obtained by using cryo-electron microscopy. The observed structures provided insights in the molecular etiology of the diseases and helped to shed light on the mechanism of misfolding in the affected patients.