Historically, the classification and nomenclature of diseases has not been systematic and diseases were either classified by cause, presenting symptoms and signs, pathological features and organs involved, or they were named after the experts that first described them. An improved understanding of pathomechanisms, the identification of disease genes and an increase in the number of distinct disease entities led to nosological coding systems that are regularly updated and revised. On the one hand, there is a real need to revisit the nomenclature and classification systems of diseases and to update them according to new findings and coding standards; on the other hand, a change in disease names can be confusing for healthcare professionals and affected patients.