Just a few facts about rare diseases.... • The definition of a rare disease is a condition that affects less than five in 10,000 of the general population • One in 17 people will be affected by a rare disease at some point in their life, this amounts to approximately 3.5 million people in the UK • Seventy-five percent of rare diseases affect children • Thirty percent of rare disease patients will die before their fifth birthday • There are 6,000 to 8,000 recognised rare diseases • A single rare disease may affect up to about 30,000 people. The