According to the US Orphan Drug Act of 1983, a rare disease is defined as a condition that affects fewer than 200,000 people. The term orphan disease originated from pharmaceutical companies not having the resources to design and scale-up formulations to treat these diseases due to the lack of financial support for such highly specialized programs. The need for financial backing resulted in The Orphan Drug Act of 1983 that gave companies a means to develop treatments for rare diseases (NIH, 2017).
Rare diseases are caused by various reasons— most notably by genetics. However, the National Institutes of Health (NIH) states, “many rare diseases, including infections, some rare cancers, and some autoimmune diseases, are not inherited. While researchers are learning more each year, the exact cause of many rare diseases is still unknown” (NIH, 2017). Almost half of those affected by rare diseases are children (Global Genes, 2018).