In the EU, a rare disease is defined as one affecting fewer than one person in 2,000 and in the US, the Orphan Drug Act of 1983 defines a rare disease as a condition affecting fewer than 200,000 people.

Due to the low prevalence of each disease, medical expertise within the area is limited and as such care offerings are inadequate. Relatively common symptoms can hide underlying rare diseases leading to misdiagnosis and delayed treatment – many rare disease patients can go undiagnosed for years. The fact that there are often no existing effective cures adds to thehigh level of pain and suffering endured by patients and their families. Rare diseases not only affect the person diagnosed – they also impact families, friends, caregivers and society with an accompanying high treatment burden. Many rare diseases lack curative therapies, highlighting the need for improved coordination to ensure that patients have access to available treatments and services.