Hermononucleosis

A disease which causes you to become Hermione Granger (Herman, Hermanana, Hermiongle boingle boingle, Hermanmonster)

Doctor: I'm sorry, but you have Hermononucleosis.
Patient: Hermononucleosis? What's that?
Doctor: Well, the symptoms are very complicated, but basically it turns you into a frumpy, ugly little girl who has no friends and carries around enormous books, and you lose your popularity and your ability to draw.
Patient: Is it deadly?
Doctor: Not by itself, no. But the isolation and endless teasing may provoke suicide. And, unfortunately, we have not yet found a cure.