https://en.wikipedia.org/wiki/David_Fajgenbaum

> David C. Fajgenbaum (born March 29, 1985) is an American immunology researcher and author who is currently an assistant professor at the Perelman School of Medicine of the University of Pennsylvania.[1] He is best known for his research into Castleman disease.

He spent years studying the disease as a researcher. He's an exception, really.