Diseases caused by protein misfolding are an emerging pathologic category that are thought to share some basic common mechanisms and display impressive heterogeneity in terms of tissue involvement, age of onset and clinical features. The growing recognition of the impact that protein misfolding has on human diseases is certainly related to the phenomenon of population aging and the expansion of the population in which these diseases are more frequent, but it is also based on a scientific revolution that looks at protein dynamics and relates these data to their potential pathologic implications. The multidisciplinary exchange of knowledge between experts in apparently unrelated diseases, such as sickle cell anemia and Alzheimer’s disease, has helped clarify the pathogenesis of these and many other diseases. The quick expansion of knowledge on the mechanisms of these diseases is priming pharmaceutical research that is now providing the first prototype drugs.