RDI's Operational Description of Rare Diseases

RDI, in collaboration with a global panel of experts, has developed an internationally endorsed Operational Description of Rare Diseases, which explains what diseases are considered rare, how many people are affected, and why the rare disease community requires specific attention. The Operational Description will serve as a common point of reference to improve the recognition of all rare conditions, inform a wide range of stakeholders, and allow a baseline to monitor change at local, national, and international levels.
This definition refers to a rare disease as a medical condition with a specific pattern of clinical signs, symptoms and findings that affects fewer than or equal to 1 in 2000 persons living in any WHO-defined region of the world. It also states that “Rare diseases include, but are not limited to, rare genetic diseases. They can also be rare cancers, rare infectious diseases, rare poisonings, rare immune-related diseases, rare idiopathic diseases and rare undetermined conditions. While the frequency of most rare diseases can be described by prevalence, some rare diseases, such as rare cancers and rare infectious diseases, can be more precisely described by incidence".
The description is part of RDI’s Memorandum of Understanding with the World Health Organization (WHO). RDI has thus developed a definition that recognises the distinct challenges, burden, and impact on Persons Living with a Rare Disease, their families, health systems, and society.


