Porphyria
About eight enzymes are required to synthesize heme, which is an essential component of hemoglobin (the protein that gives blood its red color and enables it to carry oxygen) and of other proteins, including liver enzymes. Faults in any of the enzymes result in reduced production of heme and its successor compounds and eventually the overaccumulation of predecessor compounds called porphyrins. These are toxic to cells in large quantities and can cause skin necrosis and nerve damage. Mark Warner seemed to display symptoms of both kinds of porphyrias, which would be an unlucky combination to say the least.

Cameron: You were with House? When it happened? To his leg?
Stacy: You’re interested in him.
Cameron: We went on one date. It didn’t go very well.
Stacy: Our first date didn’t, either. I was never going to see him again. Week later I moved in. 5 years. What would you like to know?
Cameron: What was he like before his leg?
Stacy: Pretty much the same.

Cameron: Any family history?
Stacy: Of? Whacked-outness? His sister voted for Nader, twice. That’s about it.

Stacy: Elevate the words all you want, you were just screwing with him. Low even by your standards.
House: Medical screwing. It’s what I do.
Stacy: And then you run away like a 12-year-old. Go hide on the roof like you always do.
House: I haven’t been up here in five years.

Dr. Cameron: Who?
House: His wife.
Dr. Cameron: The woman you used to live with.
House: That's her Indian name. On her driver's license it's "Stacy."

Dr. Cuddy: I want to run something by you.
House: I will not have sex with you! Not again! It was miserable the first time – your desperate administrative need!

Stacy: I’m not over you. You were, you were the one, you always will be. But I can’t be with you.
House: So I’m the guy, but you want the other guy, who by definition can never be the guy.

Stacy: (to House) Because you browbeat patients, intimidate them, lie to them. If you think you're right, you don't give a damn what they think. I did what you do all the time – the difference is, I did it to you.

Stacy: (to House) What's so great about you is you always think you're right. What's so frustrating about you is you are right so much of the time.

Stacy: Please, he'll be here.
House: Why? Because he loves you and does everything he's told?
Stacy: Because I didn't tell him you'd be here.

Dr. Cameron: What happened to everyone lies?
House: I was lying.

House: Dr. Mandingo - you're needed at the plantation house.

House is referrring to the novel Mandingo by Kyle Onstott which is about a slave in the 1840s who is having an affair with his owner's wife