For more than a decade, governments, nonprofits, and industry organizations involved in rare disease have stated as a matter of fact that there are 7,000 rare diseases or estimated the number to be between 5,000 to 8,000. The sources of these estimates are challenging to identify given the circular nature of citations among groups repeating these figures.
What’s more, these estimates have remained static even though nearly 300 new rare genetic disease descriptions are added to principal knowledge bases each year. It defies reason that so many new rare diseases are discovered from year-to-year while the total estimate used to characterize the number of rare diseases remains unchanged.
The reluctance to use a number that more accurately reflects all known rare diseases has cascading effects as it fails to represent the full spectrum of the rare disease community. It also results in incomplete estimates of the socioeconomic impact on the lives of patients, families, and society. The carry-on effect is that policymakers using incomplete or inaccurate information allocate limited resources in ways that perpetuate the disadvantages of these invisible communities of patients. And it undermines advocates seeking regulatory changes that are needed to address the special needs of rare disease communities.
RARE-X set out to get a more accurate count of the actual number of rare diseases. Its analysis, laid out in a new paper The Power of Being Counted, found that there are as many as a 10,867 rare diseases including both genetic and non-genetic diseases, as well as rare cancers. For the study, the authors divided the world of rare diseases into four distinct buckets: conditions for which a treatment is available, conditions that are considered diagnosable because e there are genotypic and phenotypic descriptions (even if more research is needed), conditions that are poorly defined, and conditions that are not currently recognized in major databases. Of those buckets, 503 rare conditions have approved treatments, 8,640 are diagnosable, and 2,227 are poorly defined.
“Ensuring that the true magnitude of rare diseases is understood and accepted is critical,” said Charlene Son Rigby, CEO of RARE-X, a collaborative global data sharing platform working to accelerate the diagnosis and therapeutic development for rare diseases. “It’s foundational to progressing work for rare disease patients and rare disease communities. That’s why this study is called The Power of Being Counted. Rare disease groups must be counted to be recognized.”
Getting a true count of the number of rare diseases is complicated for several reasons. Among those are the inconsistent ways that rare diseases are defined around the globe and the differing standards and measures various knowledge bases apply before identifying a rare disease. Recent efforts by the Monarch Initiative to count rare diseases using a computational approach to harmonize major knowledge bases found that the count may exceed 10,000 conditions. Still, many academics and advocacy groups seem hesitant to embrace this updated figure.
Already thousands of conditions included in rare disease knowledge bases are excluded when people repeat 7,000 estimate. Many more conditions have yet to be included in these disease compendiums because of their novelty, inadequate disease description, or resource constraints of expert panels who curate these knowledge bases.
“We know and fundamentally believe better counting of rare diseases will lead to better patient outcomes,” said Wendy Erler, vice president and global head of patient experience and insights for Alexion. “As somebody who works for a drug developer, I can state unequivocally, better understanding and counting of rare diseases will lead to more investment in research of these rare diseases, which then can hopefully lead to better treatments.”
Unless a disease is included and described in a principal rare disease knowledge base, it is unlikely to be diagnosed, even by the best specialist. That can have life-threatening consequences as rare diseases are frequently progressive and disabling. Rare diseases that aren’t adequately accounted for are unlikely to attract research interest and funding to understand a disease’s etiology, new approaches to medical management, and possible treatments.
“As you look at how people are diagnosed today, the doctors and clinicians everyday use this process called differential diagnostic where you compare and contrast diseases that could be associated with the patient,” said Sebastien Lefebvre, senior director of data science for Alexion and research lead for the study. “If that information’s not available, then no tools or website will be there, and the disease will not show up as an option.”