Unknown to many despite all the advances in technology, pharmaceuticals, genetics and medicine, there are over 3585 rare diseases
that modern medicine knows little about and neither do doctors know how to treat these diseases that affects more than 300 million people globally!
represent a growing global problem. Until now, the lack of data made it difficult to estimate their prevalence. Created and coordinated by Inserm, the Orphanet
(the online portal for rare diseases and orphan drugs) database, which contains the largest amount of epidemiological
data on these diseases taken from the scientific literature, has made it possible to obtain a global estimate. (Inserm is the French National Institute of Health and Medical Research)
Under the coordination of Inserm US14 Director Dr Ana Rath, these data have shown that more than 300 million people worldwide are currently living with a rare disease
. The study, published in the European Journal of Human Genetics, is the first to analyze the available data on rare diseases
with such precision.
Polycythemia vera, systemic sclerosis and Marfan syndrome are but just some of these are obscure conditions, which are still largely unknown by the general public and differ broadly in their clinical expression. They do have one thing in common: they are very rare.
The European community definition of a rare disease
is when the disease affects fewer than 5 in 10,000 people. Few studies have been performed by the scientific community, and there is a lack of health professional expertise and of suitable treatments. This means that the thousands of rare diseases
identified over the years cause immense suffering to many patients and their families, throughout the world.
Furthermore as it only affects a few people, the medical and pharmaceutical conglomerates are hesitant to invest any monies into research into something that is not profitable for them!
The few epidemiological
studies published on the subject so far rarely use general population registries. This made it difficult to establish their exact prevalence.
However such figures are needed if we are to identify priorities for health and research policy, understand the societal burden of these diseases, adapt the management of patients and, more generally, promote a real public health policy for rare conditions. "Given that little is known about rare diseases
, we could be forgiven for thinking that their sufferers are thin on the ground. But when taken together they represent a large proportion of the population. Although rare diseases
are individual and specific, what they have in c
ommon is their rarity, and the consequences which result from that", emphasizes Ana Rath, from Inserm US14
(Information and service platform for rare diseases
and orphan drugs).
Study author Dr Stéphanie Nguenguan (Inserm US14
), and her colleagues, used the Orphanet
database to shed light on the issue.
Developed in 1997 by Inserm
has progressively transformed into a Consortium of 40 countries, which are principally located in Europe. These partners work together to pool within it the available data on rare diseases
taken from the scientific literature, making Orphanet the most comprehensive resource in the field. The large amounts of information it containes can improve the understanding of these conditions.
Rath's team examined the data available on the point prevalence of 3,585 rare diseases
(namely, the number of people affected at a given time). Rare cancers as well as rare diseases caused by infection or poisoning were excluded from their analysis.
After analyzing the literature data using a predefined method, following which they added together the point prevalences of the various rare diseases
referenced in the database, they were able to estimate that at any given time, 3.5 to 5.9% of the global population suffers from these conditions. This represents around 300 million people, i.e. 4% of the world's population.
When collated together, "rare" diseases are not so rare after all, and therefore public health policies at global and national level are needed to address this issue, according to the authors. Such a policy is becoming reality in France, which launched its 3rd National Rare Diseases
Plan a year ago
Dr Ana Rath commented to Thailand Medical
News during a phone interview "In all likelihood, our data represent a low estimation of the reality. The majority of rare diseases are not traceable in healthcare systems and in many countries there are no national registries. Making patients visible within their respective healthcare systems by implementing means to record their precise diagnoses would make it possible in the future not only to review our estimations, but more fundamentally to improve the adaptation of support and reimbursement policies.”
More observations were made during this study, with the researchers showing for example that out of the more than 6,000 rare diseases
described in Orphanet, 72% are genetic and 70% start in childhood. Furthermore, among the diseases analyzed in the study, 149 alone are responsible for 80% of cases of rare diseases
Future research must now focus on collecting and analyzing the data on the rare diseases which had been excluded from this study. Cancers
and other rare diseases
caused by infectious agents or linked to environmental factors will be the subject of new analyses. But the researchers' priority remains the same: namely, to broaden the field of knowledge on rare diseases
in order to offer patients better treatment and ensure that, in the future, no-one is left behind.
To date, it is estimated that including rare cancers and rare diseases
caused by infectious agents, the database of rare diseases
might actually swell to close to more than 9,000 rare diseases
! Far more that the current database of diseases that modern medicine knows about.
Reference: Estimating cumulative point prevalence of rare diseases: analysis of the Orphanet database. Stéphanie Nguengang Wakap, Deborah M Lambert, Annie Olry, Charlotte Rodwell, Charlotte Gueydan, Valérie Lanneau, Daniel Murphy, Yann Le Cam, Ana Rath. European Journal of Human Genetics (2019). doi: 10.1038/s41431-019-0508-0.
Orphanet Portal: https://www.orpha.net/consor/cgi-bin/index.php
Inserm Portal: https://www.inserm.fr/en