Developing a Common Language for Rare Diseases

There is no clear agreement as to what constitutes a rare disease, the actual number of rare diseases, and how individual rare diseases are defined. The lack of clarity on the matter is not just an academic issue. The consequences of this, say researchers, is that it slows the diagnostic process and impedes the development of needed therapies for these conditions. In a recent commentary in the journal Nature Reviews Drug Discovery, Melissa Haendel and her co-authors discuss their efforts to characterize, define, and harmonize the definitions of rare disease through the Monarch Disease Ontology initiative. We spoke to Haendel, associate professor of medical informatics and clinical epidemiology at the Oregon Clinical and Translational Research Institute, about the problem with the different way organizations characterize and define rare diseases, the challenges of aligning these definitions, and why harmonization is critical for making progress in diagnosing and treating these conditions.