More than 300 million people worldwide suffer from diseases considered rare, according to a study published in the European Bulletin of Human Genetics.
Systemic sclerosis, polycythemia or Marfan syndrome are some of the diseases that remain unknown to most audiences, but when analyzed together "represent a large proportion of the population," said study coordinator Ana Rath, director of the Inserm platform. US14, which has been running the Orphanet database since 1997, which gathers data on these diseases collected by a consortium of 40 countries.
Of the more than 6,000 diseases described in the database, 149 are predominant and account for 80% of rare disease cases worldwide. It is also noted that 72% are of genetic origin and 70% begin to manifest in childhood.
The researchers, who examined data on the prevalence of 3,585 different diseases, estimate that between 3.5% and 5.9% of the population suffers from these diseases.
According to the current definition in Europe, a disease is considered rare when it affects less than five out of 10,000 people, but there are few scientific studies available and lack of medical knowledge about treatments, causing suffering for thousands of diseases and their families.
"Since little is known about rare diseases, we may think that patients are few. Although rare diseases are individual and specific, they have in common the fact that they are rare, with the resulting consequences," Rath said.
In their research, the team led by Ana Rath ruled out rare cancers or diseases caused by infections or poisoning.