Most rare diseases are genetic in origin and thus are present throughout the person's entire life, even if symptoms do not immediately appear.
This was the first count since 1983, demonstrating that there were >10,500 rare diseases where prior estimates had been ~7,000 in the Orphan Drug Act.
This definition is essentially the same as that of the Orphan Drug Act of 1983, a federal law that was written to encourage research into rare diseases and possible cures.
[10] Diseases that are statistically rare, but not also life-threatening, chronically debilitating, or inadequately treated, are excluded from their definition.
[8] But in the United States and the European Union, "orphan diseases" have a distinct legal meaning.
The Global Genes Project estimates some 300 million people worldwide are affected by a rare disease.
The European Organization for Rare Diseases (EURORDIS) estimates that between 3.5 and 5.9% of the world's population is affected by one of approx.
An example is cystic fibrosis, a genetic disease: it is rare in most parts of Asia but relatively common in Europe and in populations of European descent.
Similarly, there are rare genetic diseases among the Amish religious communities in the US and among ethnically Jewish people.
A rare disease is defined as one that affects fewer than 200,000 people across a broad range of possible disorders.
[20][21] Among numerous possibilities, rare diseases may result from bacterial or viral infections, allergies, chromosome disorders, degenerative and proliferative causes, affecting any body organ.
[28] In January 2018 NHS England published its Implementation Plan for the UK Strategy for Rare Diseases.
[29] In January 2021 the Department of Health and Social Care published the UK Rare Diseases Framework, a policy paper which included a commitment that the four nations would develop action plans, working with the rare disease community, and that "where possible, each nation will aim to publish the action plans in 2021".