From Redditor u/Aderyn_Sly:
Natalie McDonald, a first year student in Harry Potter And The Goblet Of Fire, was a real person. She was a nine-year-old girl from Toronto, Canada, who was dying of leukemia who wrote to JK asking what was going to happen in the next Harry Potter book because she would not live long enough to read it. By the time that she emailed back, Natalie had passed away the day before, never having a chance to read it. In tribute, JK wrote her in as a first-year student at Hogwarts who was sorted into Gryffindor House by the Sorting Hat.