**FILE**Tourists frequently visit the graves of Randolph and Sarah McCoy, which are marked by the tombstone seen in Pikeville, Ky., on April 23, 2003. The most infamous feud in American folklore, the long-running battle between the Hatfields and McCoys, may be partly explained by a rare, disease inherited by the present-day McCoy clan that can lead to hair-trigger rage and violent outbursts.The last time ithe feud surfaced was in January 2003. McCoy descendants sued Hatfield descendants over visitation rights to a small cemetery on an Appalachian hillside in eastern Kentucky. It holds the remains of six McCoys, some allegedly killed by the Hatfields.(AP Photo/Roger Alford)