Registries of rare diseases: current knowledge and future perspectives

In Europe, a rare disease is a condition that affects less than 1 in 2000 citizens. Over 6000 different rare diseases have been identified to date but only 700 of them are covered by active European registries. Due to the low prevalence of rare diseases, the main sources of clinical knowledge are case reports, case series or small observational studies. The AIDA Registry dedicated to Behçet syndrome (BS) represents a step toward an international and multidisciplinary collaboration. The huge amount of data potentially included could improve our current clinical knowledge on BS, as well as inspire new clinical trials to test novel treatments.