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. ‘This condition can certainly make anybody short-tempered, and if they are prone because of their personality, it can add fuel to the fire,’ said Dr. Revi Mathew, a Vanderbilt University endocrinologist treating one of the family members. The Hatfields and McCoys have a storied and deadly history dating to Civil War times. Their generations of fighting over land, timber rights and even a pig are the subject of dozens of books, songs and countless jokes. Unfortunately for Appalachia, the feud is one of its greatest sources of fame. Several genetic experts have known about the disease plaguing some of the McCoys for decades, but kept it secret. The Associated Press learned of it […]