### Question
How is the "rare disease" defined?


### Answer
The term **rare disease** is defined in *42 U.S.C. § 287a* as follows -

> any disease or condition that affects less than 200,000 persons in the United States

#### Citation:
  - *42 U.S.C. § 287a*
  - Heading: **CHAPTER 6A-PUBLIC HEALTH SERVICE > SUBCHAPTER III-NATIONAL RESEARCH INSTITUTES > Part E-Other Agencies of NIH > subpart 1-national center for advancing translational sciences**

