Rare Diseases

There are more than 6,000 rare diseases known today and they affect an estimated 25 million persons in the U.S. In the U.S. today, rare diseases are defined by the National Institutes of Health (NIH) and the U.S. Food and Drug Administration (FDA) as any disease affecting fewer than 200,000 Americans. In Europe rare diseases are defined as a disease that affects less than 1 in 2000 individuals.

This page was last updated on July 8, 2010.