Who is Patient X?

Question

Right at the start of the Prologue, there are emails and articles about Patient X and how he can accept augs without rejection. Are they referring to Adam? He seems to fit the bill for this, but I thought he wasn't (noticeably?) augmented—so how would they know—until after the incident that kicks off the game.

So who is Patient X?

Answer 1

You are -- later in the game Megan Reed confirms it, and you discover clues by doing the various sidequests. While you were an infant a corporation experimented on you and a few dozen other babies; you were the only one to survive the modifications and come through, but the scientists who worked on you caught a bad case of remorse and torched the place after smuggling you out.

Answer 2

It is ...

Adam Jensen.

Throughout the game there are several hints towards that possibility and near the end it is stated outright.

Answer 3

I haven't finished the game (or looked at any other answer here), but it has to be…

Adam Jensen. From the fact that he has zero need for neuropozine; he was genetically experimented on as an infant; the comment Sarif made in Jensen's appartment; and Megan's team only got the Patient X info when he was hired.