Any disease which affects fewer than 5 out of 10,000 people in Europe is defined as a rare disease. This figure may seem low, but it is important to recall that there at least 5,000 distinct rare diseases affecting individuals within Europe. This means that between 6-8% of the population - or 27-36 million people - are living with rare diseases.
Researching rare diseases can be challenging because of the low numbers of people living with a specific condition. Governments may offer incentives to researchers to study and develop treatments for rare diseases when this research would otherwise not be financially viable. Diseases in this category are referred to as orphan diseases.
Patients living with rare diseases may benefit from research into therapies for related, more common conditions. Where this is the case, we will signpost to relevant, useful information as clearly as possible.