Orphan diseases affect too few people to interest the investment of capital in research for cures and therapies. There are various definitions of what precisely constitutes an orphan disease or a rare disorder.
Rare disorders strike people of all ages, races and ethnic background. Many of these disorders are genetic, for example: Tay Sachs disease, Huntington's disease and cystic fibrosis. Some disorders are acquired such as AIDS and legionnaires' disease. A number of rare disorders fall within the realm of widespread health conditions such as heart disease and cancer.
The Canadian Organization for Rare Disorders claims that one in twelve individuals in Canada have been diagnosed with a rare disorder. There are more than 5,000 rare disorders that, taken together, affect approximately 2.5 million Canadians. A rare or "orphan" disease affects fewer than 20,000 people in Canada.
A rare or "orphan" disease affects fewer than 200,000 people in the United States. There are more than 5,000 rare disorders that, taken together, affect approximately 20 million Americans. One in every 12 individuals in this country has received a diagnosis of a rare disease.