What is a rare disease?

A disease is defined as rare when it affects less than 1 in 2,000 citizens

No-one knows for sure how many people with Behçet’s disease there are in the UK, but it is estimated that there may be about 0.64 in 100,000 – that is, about 600 people.

Patients with rare diseases are the orphans of health systems, often without diagnosis, without treatment, without research, and therefore without reason to hope.

Rare diseases are life-threatening or chronically debilitating diseases with a low prevalence and a high level of complexity.

Patients with very rare diseases and their families are particularly isolated and vulnerable. The life expectancy of patients with rare diseases is significantly reduced, and many have disabilities that become a source of discrimination and reduce or destroy educational, professional or social opportunities. Research on rare diseases is scarce.