About Rare Diseases

Those living with rare diseases, defined as affecting fewer than 200,000 people in the United States1, are often isolated and underserved. In fact, of the approximately 7,000 types of rare disease, fewer than five percent possess even one FDA-approved treatment2.

Our medications help support patients living with rare diseases, including:

  • Chronic granulomatous disease (GCD)
  • Severe, malignant osteopetrosis (SMO)
  • Urea cycle disorders (UCDs)
  • Nephrophathic cystinosis

To learn more about rare diseases and the specific conditions where we are focusing our efforts, visit Disease Information.


  1. Rare Diseases Act of 2002. 21 U.S. Code § 360bb. https://www.congress.gov/bill/107th-congress/house-bill/4013/text
  2. Miyamoto BE, Kakkis ED. The potential investment impact of improved access to accelerated approval on the development of treatments for low prevalence rare diseases. Orphanet Journal of Rare Diseases. 2011;6(1):49. doi:10.1186/1750-1172-6-49.