Because each rare disease by definition affects a small number of people, in total "more than 300 million people live today" with a pathology of this type, it is estimated that 4% of the world's population, according to the first estimate. about the phenomenon
"Therefore," rare "illnesses are not rare if they are collectively taken and justified in the application of public health policies worldwide and nationally," He gave a statement to researchers from the National Institute of Health and Medical Research (Inserm) of France.
A sickness is denominated "rare" when it does not affect to more than 5 of every 10,000 personas, the French institute of investigation recuerda.
For a long time, the estimate of its prevalence was difficult due to the lack of data.
French researchers have used the Orphanet base, created and coordinated by the Inserm, "which contains the largest number of epidemiological data on these pathologies."
The figure of 300 million is "probably a poor estimate of reality," estimates Ana Rath, Orphanet's director, because "the majority of rare diseases are not traceable in health systems and there are no national records in most of them. countries ".
His team has also shown that out of the 6,000 or so identified diseases in Orphanet, 149 are responsible for 80% of the usual sick cases.
Elsewhere, 72% are of genetic origin and 70% started from childhood.
Having such estimates is important "to set priorities for health and research policies, to address the burden of these diseases, to adapt the care to patients and the general public, to promote a true public health policy on the diseases. rare, "explain the authors of the study.
The work was published on September 16 in the European Journal of Human Genetics.