A nice AP story talks about the hypothesis that much of the fuel for the famed Hatfield-McCoy feud might be attributed to Von Hippel-Lindau disease, a rare genetic disorder that predisposes those affected to highly-vascularized tumors. The reasoning is that adrenal tumors might be responsible for many of the McCoys' notorious tempers. There are some great quotes from actual family members in the article.

I always liked reading and writing about Von Hippel-Lindau. The VHL tumor suppressor deactivates angiogenesis in an interesting oxygen sensing pathway. Normally VHL signals the degradation of hypoxia inducible factor HIF1alpha. In hypoxic conditions, or in the presence of a deactivating VHL mutation HIF1alpha and other protein players initiate transcription of pro angiogenic genes.

A book I recently reviewed for the magazine had another take on the famous Appalachian feud. David Sloan Wilson's Evolution for Everyone mentions research which reasons that a code of behavior adopted long ago by the Scots-Irish who moved to southern and eastern mountain regions of the United States held a sense of family honor very highly. Members of a family or group would risk life and limb to protect the reputation of the group. Research has shown that people from this background are more prone to aggression in certain experimental situations, although it's hardly a perfect science.

VHL might play a role in the violence, but I wouldn't want to start making generalizations. Hatfields, McCoys, and many others from that area of the country have suffered their fare share of sweeping statements. As Marilynn Marchione from the AP writes, 'Unfortunately for Appalachia, the feud is one of its greatest sources of fame.' Even more unfortunate is another oft-cited source of fame that doesn't bode well in terms of human genetic disease, inbreeding.