New clinical classification of rare cardiovascular diseases and disorders: relevance for cardiovascular research

Every year, based on basic and clinical research findings, new scientific statements or updates to clinical practice guidelines are published. Wide dissemination and implementation of them lead to improvements in our understanding of diseases and disorders and in clinical care. Progress is also observed in cardiovascular research concerning rare cardiovascular diseases and disorders (RCDD). However, due to the infrequency of these diseases and disorders and the relative paucity of reliable basic research and clinical evidence, collaboration between clinicians and scientists from many centres and various scientific backgrounds is crucial. Such co-operation should also aim to gather evidence for better recognition of the pathogenesis of RCDD. Getting to know the molecular mechanisms of RCDD may result in introduction of novel disease modifying therapies in the field of RCDD. Clinical classification of RCDD aids in the visualization and enhancing insight in common pathways implicated in the spectrum of RCDD and enables a systematic approach, including differential diagnosis, to these diseases and disorders. Such a classification was first published in the Journal of Rare Cardiovascular Diseases (JRCD) in 2013 and is available for free at www.jrcd.eu.1–3 However, since this publication, progress has been made in both the understanding of pathogenesis and management of RCDD.4–9 Furthermore, we have received many valuable comments from scientists and clinical practitioners, necessitating an updated version of RCDD classification.