Operational Description of Rare Diseases

In collaboration with a global panel of experts, RDI 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 Description is a common reference to improve the recognition of rare diseases within health systems and support the development of policies that address the challenges faced by Persons Living with a Rare Disease (PLWRD).

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.

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

To develop and implement policies for PLWRD, public health agencies and governments need a common reference – a definition of rare diseases and their impact.

Attempts to define rare diseases often prioritise disease prevalence thresholds and frequency; in contrast, an operational description considers the specific clinical and qualitative challenges associated with the low prevalence of rare diseases.

The Operational Description will serve as a common point of reference to inform a wide range of stakeholders, including policymakers, and allow a baseline to monitor change at local, national, and international levels.

The proposed Operational Description of rare diseases describes WHAT diseases are considered rare, HOW MANY persons are affected, and WHY the rare disease community demands specific attention and policy action to address the impact and burden of rare diseases on patients, their caregivers and families, healthcare systems, and society overall.

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

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.

Experts PANEL

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