(CNN) — On this rare day, leap year, we observe Rare Disease Day U.S.A.
Currently, there are more than 7,000 rare diseases.
A rare disease is defined as affecting less than one in 200,000 people.
Yet 1/10 Americans suffer from rare diseases, and more than half are children.
First observed in the U.S. in 2009, Rare Disease Day U.S.A. unites the rare disease community and helps raise awareness and education.
The zebra with its unique stripes is the official symbol of rare diseases.
Show support today by wearing something striped, and posting to social media using the hashtag show your stripes.