In an article headed Science Fiction and Fantasy Creators Who Became Their Own Genres, io9 list Charlie K. as a genre unto himself: Here's the opening:

Some people don't just create new worlds and super-memorable characters — they give life to their own genres. There are some creators of fantastical stories whose work is so distinctive, you have a pretty good sense what's going to happen when you pick up their work — and you're excited, because it's going to be a hell of a ride.

And here's Charlie's bit:

Kaufman wrote a string of movies that combined surrealism, broken characters and bitter humor, including Being John Malkovich, Adaptation, Confessions of a Dangerous Mind and Eternal Sunshine of the Spotless Mind. And then he started directing his own screenplays, with Synecdoche, New York and the forthcoming Frank or Francis. (And he's got a novel in the pipeline, about which nobody knows anything.) It's hard to pigeonhole Kaufman's work into a single genre (maybe Slipstream?) but everything he writes is instantly recognizable, from the depressed heroes to the strange plot devices to the habit of inserting a love story where you least expect it. (Source)

A few of the other folks who make the list: Joss Whedon, Kurt Vonnegut, Grant Morrison, Terry Gilliam.