Although some diseases are rare, the number of people suffering from them is significant. There are between 6,000 and 8,000 rare diseases affecting a total of 6 to 8% of Belgian people.

Varied and complex symptoms

Rare diseases are characterised by a large variety of symptoms, that not only vary between one disease and another, but that can also vary from one person to another who is affected by the same disease. 

The symptoms are often very complex, can affect multiple organs and therefore involve different medical specialties, which complicates the diagnosis

In addition, although some diseases are evident at birth, others take decades to develop.

Characteristics of rare diseases 

Rare diseases can be:

  • disabling 
  • painful
  • difficult to treat
  • chronic 
  • degenerative (reduced life expectancy)


Sciensano is responsible for processing the data from the Central Registry of Rare Diseases, which aims to centralise certain data on all Belgian patients affected by a rare disease.

QR code

QR code for this page URL