I ran across this article years ago, and thought those watching the Hatfields & McCoys may find it interesting.
The most infamous feud in American folklore, the long-running battle between the Hatfields and McCoys, may be partly explained by a rare, inherited disease that can lead to hair-trigger rage and violent outbursts.
Dozens of McCoy descendants apparently have the disease, which causes high blood pressure, racing hearts, severe headaches and too much adrenaline and other “fight or flight” stress hormones.
No one blames the whole feud on this, but doctors say it could help explain some of the clan’s notorious behavior.
You can read the article in its entirety at http://www.usatoday.com/news/health/2007-04-05-hatfield-mccloy-disease_N.htm