Approximately 7,000 rare diseases, defined by their prevalence of less than 5 per 10,000 in the community, have been identified. These diseases, most often of genetic origin, collectively affect 5-8% of the European population, or 25-30 million people. In Belgium, it is estimated that around 700,000 people have a rare disease, with often severe clinical, social and economic consequences. The diagnosis and management of rare diseases requires a concentration of expertise in highly specialised centres, working in concert with hospital networks and health professionals. Within Cliniques universitaires Saint-Luc (CUSL), the Institute of Rare Diseases (IMR) coordinates some thirty centres of reference for rare diseases, involving more than 15,000 patients and 300 health professionals. Fifteen of the CUSL centres are part of the European Reference Networks (ERNs), officially validated and supported by the European Community. Patients and their treating physicians often find themselves at a loss when faced with rare diseases and the difficulties they entail. The setting up of multidisciplinary networks bringing together a critical mass of medical, biological and technical expertise and the recruitment of a sufficient number of patients are essential to optimise the management of these diseases. One of the key missions of the CUSL Rare Disease Institute is to establish an information and support programme for patients, their families and health professionals. It is within this framework that the RMI organised a symposium on Friday 3 June 2002 on the theme of innovation in the field of rare diseases. Speakers from Belgian and foreign centres covered a wide interdisciplinary field, from basic research to clinical practice, genetics, therapeutic innovation, drug repositioning, the use of artificial intelligence and medical data, as well as ethical and economic aspects and, of course, the views and expectations of patients. As you will read in the following pages, the presentations of this symposium have shown a tremendous momentum in the holistic management of rare diseases. This momentum is irreversible and is part of the global awareness of the medical and societal importance of these diseases.

In Europe, a disease is defined as rare when its prevalence is less than 1 in 2,000. The management of patients with rare diseases refers to the complex and heterogeneous status of some 6,000 to 8,000 diseases, 80% of which are of genetic origin. Rare diseases mostly affect children. Due to the large phenotypic heterogeneity, rarity and unusual nature of rare diseases, the affected patients regularly encounter a lack of knowledge regarding their disease, which is most often associated with diagnostic wavering until an accurate diagnosis is made and lack of treatment.

In order to draw attention on and address this issue, the European Commission has been developing initiatives aiming to ensure the development of concrete measures for the patients and their families across its member states for more than two decades.

Responding to this call, Belgium is committed to improving the management of rare diseases and has thus developed a national plan. Multidisciplinary diagnostic structures were created and supported, partnerships with European reference networks were established, and registers were set up in order to centrally and uniformly collect patient data. This article offers an overview of the characteristics of rare diseases, as well as an inventory of existing measures in both Europe and Belgium.