In order to address the main challenges related to the rare diseases (RDs) the European Commission launched the European Reference Networks (ERNs), virtual networks involving healthcare providers (HCPs) across Europe. The mission of the ERNs is to tackle low prevalence and RDs that require highly specialised treatment and a concentration of knowledge and resources. In fact, ERNs offer the potential to give patients and healthcare professionals across the EU access to the best expertise and timely exchange of lifesaving knowledge, trying to make the knowledge travelling more than patients. For this reason, ERNs were established as concrete European infrastructures, and this is particularly crucial in the framework of rare and complex disease...