Nashville (AP) -- 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.
No one blames the whole feud on this, but doctors say it could help explain some of the clan's notorious behavior.
Doctor Revi Mathew is a Vanderbilt University endocrinologist treating one of the family members. He says the condition can make anybody short-tempered.
The Hatfields and McCoys have a storied and deadly history dating to Civil War times. Their generations of fighting are the subject of dozens of books, songs and countless jokes.
Several genetic experts have known about the disease for decades, but kept it secret. The Associated Press learned of it after several family members revealed their history to Vanderbilt doctors, who are trying to find more McCoy relatives to warn them of the risk.
Copyright 2007 by the Associated Press. All rights reserved.