Abstract
Fibrodysplasia ossificans progressiva is one of the most devastating constitutional diseases of the bone, and may be a valid example to establish the role of Primary Care in the care of rare diseases. Although rare diseases usually present with marked anomalies, they can mimic signs and symptoms of common disorders, with the risk of going unnoticed. For this reason, all health professionals should proceed with a reasonable suspicion when confronted with a patient with an apparently common disease with atypical symptoms and a non-conventional progress. The care given by the Primary Care team along with other health care services are fundamental in the integrated and individualised follow-up. The quality of care in rare diseases must not be inferior to that provided to the other chronic diseases, since, besides being a requirement of justice and fairness, these patients are, in essence, the "paradigm of chronicity".