User blog comment:Tomj8937/Who are the 2 lost primarch's:/@comment-1583177-20100826220709/@comment-1257337-20100827082958

Actually, officially they were eaten, since then GW has been trying to remove it from player's minds and make them forget. i remember reading somewhere that one of Jervis' regrets is not removing squats before 2nd edition. They are no longer technically canon. No idea about A and O another mystery that will piss us of forever most likely.

Sorry for lack of referencing but can't remember where i found the info