Dorek Syndrome was a rare and deadly Ferengi disease. Only one in five million Ferengi were diagnosed with Dorek Syndrome and diagnosis could come with only a few days to live.
Quark was mistakenly diagnosed with Dorek Syndrome in 2372 by Doctor Orpax. Upon learning this, Quark wanted to sue Orpax for malpractice. (DS9: "Body Parts")
According to the script, this syndrome's name was pronounced as "doe-RECK".