How did uncommon disorders become 'rare diseases'? History of a boundary object.

The category of 'rare diseases' has been in growing use in the fields of public health and patient advocacy for the past 15 years in Europe. In this socio-historical inquiry, I argue that this category, which appeared initially as a by-product of the orphan drug issue in the United States of America, is a boundary object. As such, it has different specific local uses: a meaningless category for physicians, it relates to the patients' experience of illness, whereas the pharmaceutical industry first considered it as being synonymous with small markets and then with innovation. Public bodies contributed to framing a common and blurred use, based on a statistical definition whose purpose was to foster co-operation between the four groups involved in the issue. In the definition process of the category of rare diseases, the key actors were the patients and public bodies, not medical professionals or the pharmaceutical industry.