Operational Description of Rare Diseases

What is a rare disease? What challenges are associated with rarity for Persons Living with a Rare Disease?

RDI, working with a global panel of experts and collaborating with the WHO ICD, the International Classification of Diseases, has developed an internationally endorsed Operational Description of Rare Diseases.

The description explains what diseases are considered rare, how many people are affected, and why the rare disease community requires specific attention.

The Description is a common reference to improve the recognition and visibility of rare diseases within health systems and support the development of new actions and policies to address the challenges faced by Persons Living with a Rare Disease (PLWRD).

The description is part of RDI’s Memorandum of Understanding with the World Health Organization (WHO).

Improving health and social equity for Persons Living with a Rare Disease (PLWRD) and their families is increasingly recognised as a global policy priority.

This commitment is expressed in the Political Declaration on Universal Health Coverage (2019) which includes mention of rare diseases, and the UN Resolution on “Addressing the Challenges of Persons Living with a Rare Disease and their Families”, adopted in December 2022.

Attempts to define rare diseases are often shaped by regulatory processes and prioritise disease prevalence thresholds and frequency. In contrast, the Operational Description considers the specific clinical and qualitative challenges associated with rarity and the low prevalence of rare diseases.

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.

A definition that recognizes the distinct challenges, burden, and impact on Persons Living with a Rare Disease, their families, health systems, and society.

Experts PANEL

RDI collaborates with a global panel of rare disease experts to propose an internationally recognised Operational Description of rare diseases composed of a core definition of rare diseases complemented by a descriptive framework.

Roberta Anido de Pena	Iberoamerican Alliance for Rare Diseases (ALIBER), Federación Argentina de Enfermedades Poco Frecuentes (FADEPOF), Argentina
Diego Ardigò	Chiesi Pharmaceuticals, Italy
Gareth Baynam	Rare Care- Clinical Centre of Expertise for Rare and Undiagnosed Diseases, Perth Children’s Hospital, Western Australia, Australia
Hugh Dawkins	DA Precision Health, Australia
Ada Hamosh	Johns Hopkins School of Medicine, Online Mendelian Inheritance in Man (OMIM), USA
Robert Jakob	Health Statistics and Information Systems, World Health Organisation, Switzerland
Eva Krpelanova	Health Statistics and Information Systems, World Health Organisation, Switzerland
Yann Le Cam	EURORDIS – Rare Diseases Europe, France
Helen Malherbe	Rare Diseases South Africa, South Africa
Jane Millar	International Health Terminology Standards Development Organisation (IHTSDO), SNOMED International, UK
Caron Molster	Office of Population Health Genomics, West Australia Department of Health, Australia
Lucia Monaco	International Rare Diseases Research Consortium, Fondazione Telethon, Italy
Carmencita Padilla	University of the Philippines Manila, Philippines
Anne Pariser	National Center for Advancing Translational Sciences (NCATS), NIH, USA
Ana Rath	Orphanet, INSERM, France
Peter Robinson	The Jackson Laboratory, USA
Franz Schaefer	ERKnet European Reference Network, Heidelberg University Hospital, Germany
Stefanie Weber	Code Systems, Federal Institute for Drugs and Medical Devices (BfArM), Germany

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Additional references and documents will be included