Rare Disease Directory
It is easy to think that you have never known someone with a rare disease because you have never heard of Amyloidosis, Niemann-Pick Type C or Periodic Fever Syndrome (PFS). However, a disease is classified as "rare" if it affects fewer than 200,000 Americans. These diseases typically lack financial incentive to make and market new treatments even though 25 million Americans are diagnosed with one of over 7,000 rare diseases. What's more surprising is that you probably have heard of some of them - cystic fibrosis, leukemia, non-hodgkins lymphoma or even ALS - you just haven’t realized they were classified as "rare." Use the index to the left or below to browse the full list of rare diseases provided by the National Institutes of Health (NIH) Office of Rare Diseases.