The challenge of developing information systems for rare diseases is in harmonizing social care conditions and health care conditions with the focus on personalization and patient autonomy. Knowledge about the most rare diseases is limited, which is the result of poorly funded research and the existence of only a few specialized experts. Furthermore, the treatment and care of the affected patients is very complex, cost-intensive, time critical, and involved stakeholders are very heterogeneous. The information needed by the patient depends on his or her personal situation and constitution. To support the information logistics between patients of rare diseases and (all) other stakeholders (e.g. physicians, therapists, and researchers), we developed an information system with Linked Open Data technologies in order to create a platform and tool independent solution addressing the heterogeneity of the stakeholders. To engineer system and data model requirements of our approach we analyzed the rare disease
Amyotrophic Lateral Sclerosis
(ALS), which have wide-spreaded characteristics. The resulting formal knowledge representation was encoded in OWL, which allows, for instance, a modular development of complex areas and also the re-usage of existing knowledge bases.