The source material in this case is "Vitus", a 2007 film that represented Switzerland's official entry for the Best Foreign Film Oscar (it was not nominated). We're not necessarily familiar with the film, which stars the prolific Bruno Ganz ("Downfall") as the father, though critics seem to have been mixed, if Metacritic and Rotten Tomatoes are anything to go by. Which is to say, they aren't, and we should really just see the movie for ourselves. Regardless, this does seem miles away from Gluck's bread and butter, which is directing mostly conservative, young-skewing films about sex.
Gluck was meant to start shooting an untitled comedy this past summer with Emma Stone, though that never seemed to materialize. He's also working on an adaptation of "About Last Night..." as well as "Sex On The Moon", a caper film where a man plots to steal moon rocks as part of an elaborate stunt that will... get him laid. Man, if it weren't for this new project, we'd say this Gluck cat's got a one-track mind.