What is a rare disease?
How many people live with a rare disease?
Why do Persons Living with a Rare Disease and their families require specific attention?
RDI, working with a global panel of experts and collaborating with the World Health Organization (WHO) ICD has developed an internationally endorsed Operational Description of Rare Diseases.
Carine Alsokhn | Health Statistics and Information Systems, World Health Organisation (WHO), Switzerland |
Roberta Anido de Pena | 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 (WHO), Switzerland |
Eva Krpelanova | Health Statistics and Information Systems, World Health Organisation (WHO), 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 |
ELEMENTS OF THE DESCRIPTION
The Operational Description of Rare Diseases is composed of two elements:
PLWRD FACE COMMON CHALLENGES
Persons Living with a Rare Disease (PLWRD) face distinct and significant challenges that arise from the infrequency of their medical condition.
Challenges include a long diagnostic journey, inadequate clinical management, and limited access to knowledge and effective treatments.
The burden of rare diseases on patients, caregivers, their families, healthcare systems, and society overall, needs greater visibility and recognition.
A rare disease is 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 World Health Organisation-defined region* of the world.
* WHO-defined regions are: Africa, Americas, Eastern Mediterranean, Europe, South-east Asia, Western Pacific
EQUAL OR FEWER THAN 1 in 2000 PERSONS
RARE DISEASES INCLUDE, BUT ARE NOT LIMITED TO, RARE GENETIC DISEASES
Rare diseases include, but are not limited to, rare genetic diseases, 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 (the number of cases within a specific population at a given moment or over a specified period), some rare diseases, such as rare cancers and rare infectious diseases, can be more precisely described by incidence (the rate of new cases within a specific population over a particular period).
Identifying what diseases are rare and how many persons are affected are vital steps. However, to make the core definition operational, so it guides new actions and policies, it must provide context to illustrate to policymakers why the rare disease community requires their attention.
The descriptive framework is an essential complement to the core definition of rare diseases.
1. PERSONS LIVING WITH A RARE DISEASE FACE DISTINCT CHALLENGES THAT ARISE FROM THE INFREQUENCY OF THEIR MEDICAL CONDITIONS
There is a limited understanding of medical conditions with low frequency in the general population. This is primarily due to the scarcity of affected individuals per condition and the subsequent absence of data.
PLWRD often experience prolonged periods without a diagnosis, and many remain undiagnosed. Patients are also more likely to experience misdiagnoses, resulting in inappropriate treatment and disease progression.
Even with a diagnosis, the clinical management of patient care is often inadequate. Without sufficient knowledge about a rare disease, clinicians cannot assess the condition’s complexity, anticipate the disease course, or standardize health management practices.
Due to the rarity of each condition, clinicians may be unaware of existing treatments.
And treatment options for rare diseases are severely limited as research and development are not prioritized, and economic incentives may be deemed insufficient to attract investment into rare diseases.
In addition, conducting small cohort trials across different countries poses methodological and ethical challenges.
When therapies are developed, high pricing regularly results in delayed and inequitable access.
2. THE BURDEN OF RARE DISEASES NEEDS VISIBILITY AND RECOGNITION
The 6000 – 8000 rare diseases collectively affect an estimated 3 – 8% of the global population or over 300 million persons globally*.
Establishing a common point of reference will enable more precise measures of the cost of rare diseases on health systems and the lives of PLWRD, their families and society.
* Nguengang Wakap S et al. Estimating cumulative point prevalence of rare diseases: analysis of the Orphanet database. Eur J Hum Genet 2020 Feb;28(2):165–73.
Beyond the physical impact, PLWRD experience psychosocial consequences such as isolation, stigmatization, and discrimination, which are nurtured by a lack of public awareness and an absence of policies and social support.
The burden of rare diseases extends to families and caregivers and society at large.
Approximately 70-90% of rare diseases start in childhood. Parents, especially mothers, assume the primary caregiving role with an impact on the financial and emotional health of the whole family. Workplace productivity loss for PLWRD and caregivers significantly contributes to the economic burden of rare diseases.
The distinct health and social challenges associated with infrequent conditions demand greater visibility and recognition by policymakers.
3. THE OPERATIONAL DESCRIPTION OF RARE DISEASES IS A CATALYST FOR ACTION
The Operational Description of Rare Diseases provides a global reference to encourage a more precise representation of rare diseases within the WHO International Classification of Diseases (ICD).
Improved codification will enhance the interoperability of data across health information systems. Additionally, a global network of shared knowledge will facilitate research collaborations, foster innovation for new treatments, and highlight the need for equitable access to care and services.
Achieving Universal Health Coverage requires that the specific needs of PLWRD are addressed.
A shared reference describing rare diseases is essential to improve health outcomes, address the social determinants of health, and facilitate the inclusion of PLWRD and their caregivers in society.
