This was just reported. A major force behind the Milestone Universe and very active in both comics and animation. So far cause of death has not been stated
http://www.comicbookresources.com/?page=article&id=30969
Oh no! Dwayne McDuffie was one of the best writers in the industry today, and I will forever be a fan of his work in DC's animation, especially JLU. I am very sad to hear this, and I can definitely say he will be missed.
That's shocking. I've been a regular lurker on his forums for a while now, and he was one of the comics creators i had greatest respect for. Been a fan ever since his first two Damage Control series, back at the start of his career.