The Deus Ex ARG at their official site has ended, revealing the game's first DLC. The Missing Link will be released in October, and will cover Adam's three-day disappearance in Human Revolution.

Players will control Adam after his augmentations become disabled, and are tasked with escaping a freighter. The site says you can "rebuild Adam's augmentation from scratch," so a respec option is likely. No specific date has been set for The Missing Link.

Source: Deus Ex Official Site