I've tried googling all kinds of combinations of the relevant keywords but somehow I can't really find anything useful since I'm totally lacking the proper knowledge to even come up with more specific search terms.
Any help would be appreciated. What kind of anything can a body fail to produce that'll lead to multiple organ failure? Oh yeah, it should also be treatable by simply replacing the lacking substance. Thanks!
Edit: Rarity isn't an issue. The rarer, the better even. And it doesn't totally have to be MOF if you can think of something better. Important is that it's a critical condition that can kill fast if left untreated.