In the United States, the Rare Diseases Act of 2002 defines "rare disease" strictly according to prevalence, specifically "any disease or condition that affects less than 200,000 people in the United States," or about 1 in 1,500 people.
В США Акт о редких заболеваниях ("Rare Disease Act") 2002 года определяет редкие болезни как «болезни или состояния, затрагивающие менее 200000 людей в США» («any disease or condition that affects less than 200,000 persons in the United States»), или примерно 1 человека из 1500.