The dynamics of causes and conditions: the rareness of diseases in French and Portuguese patients’ organizations’ engagement in research

Many actors in the field of rare diseases point to the role played by the notion of ‘rareness’ in the emergence and development of what we refer to as the ‘hybrid collective model’ (HCM) of collaboration between patients and experts. The HCM features two main characteristics: (i) the constitution of communities which bring togetherfamilies and researchers as actors in the ‘war on disease’; and (ii) organized cooperation between experts and patients’ organizations in the production of knowledge on diseases. This article seeks to highlight the reflexive work carried out by French and Portuguese patients’ organizations on the notion of rareness and its relation with the HCM. A systematic surveyand fieldwork conducted in both countries have shown that such relation is neither systematic nor univocal. Some patients’ organizations point to the limits or the lack of relevance of rareness as a category for grounding their action. These criticisms have led us to envisage a more general dynamic: the choice of the HCM as a mode of involvement in a politics of singularization-generalization of causes and conditions. We suggest some possible consequences of this singularization-generalization dynamic in the conclusion.