Gene May Affect Blood-Clot Drug's Effects

Testing for variations of a gene that helps control blood clotting could one day help doctors write better prescriptions for warfarin, a clot-preventing drug that is taken by millions of Americans and is difficult to manage, researchers report. The gene, designated VKORC1, was described only last year by a group led by Dr. Darrel W. Stafford at the University of North Carolina. Now researchers at the University of Washington in Seattle and Washington University in St. Louis say their study indicates that the version of the gene that an individual carries has a strong effect on warfarin activity. "There are two different versions of the gene, high-dose and low-dose," explained Mark J. Rieder, research assistant professor in genome sciences at the University of Washington, and lead author of the report in the June 2 issue of the New England Journal of Medicine.