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


### Answer
The term **rare disease** is defined in *42 U.S.C. § 283h* as the following:

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

#### Citation:
  - *42 U.S.C. § 283h*
  - Heading: **CHAPTER 6A-PUBLIC HEALTH SERVICE > SUBCHAPTER III-NATIONAL RESEARCH INSTITUTES > Part A-National Institutes of Health**

