Dark Heresy: Dulce et Decorum est
As you play, your character may gain “Corruption Points” due to exposure to The Warp.
Game mechanically, you record them on your record sheet as you see fit.
When you gain enough Corruption Points, the GM will assign you some random Disadvantage related to your growing Warp Taint (can vary from derangements to mutations). However, your character total is not decreased. The points gained by this new Disadvantage may be spent on improving your character in other ways (gaining Warp Powers, beneficial mutations, etc. etc.)… after all… the lure of Chaos is strong.