What are rare diseases?

A rare disease is a health condition of low prevalence that affects a small number of people compared with other prevalent diseases in the general population. It is estimated that globally around 6000 to 8000 rare diseases exist with new rare diseases being reported in the medical literature regularly.

However, 80% of all rare disease patients are affected by approximately 350 rare diseases.
Paradoxically, though rare diseases are of low prevalence and individually rare, collectively they affect a considerable proportion of the population in any country, which according to generally accepted international research is between 6% and 8%. Rare diseases include genetic diseases, rare cancers, infectious tropical diseases and degenerative diseases. 80% of rare diseases are genetic in origin and hence disproportionately impact children.