Genetic variant mimics effect of heart failure medications

The discovery, another step toward personalized medicine, may explain why beta-blockers do not work for all patients

A genetic variation, found predominantly in African Americans, protects some people with heart failure, enabling them to live longer than expected. That’s the conclusion of a research team led by investigators at the University of Maryland School of Medicine in Baltimore and the Washington University School of Medicine in St. Louis. The researchers found that the genetic variation acts just like beta-blockers, a class of drugs used to treat chronic heart failure. Study results will be available in the online version of Nature Medicine (www.nature.com), on April 20, 2008.

In the study, the researchers found that African American heart failure patients with the genetic variation had a natural protection against death and the need for a heart transplant that is the same as the protection provided by beta-blocker therapy. Those patients who were given beta-blockers did not experience additional benefits from the medications because their own “genetic beta blockade” was already protecting them.

The researchers say their discovery adds to the accumulating evidence that genetic differences contribute to the way people respond to medications, and should encourage the use of genetic testing in clinical trials to identify people who can benefit from therapy tailored to their personal genetic makeup. “This is a significant development in our understanding of why some African American patients appear to not respond to beta-blockers in the same way as Caucasian patients,” says one of the study’s co-authors, Stephen B. Liggett, M.D., professor of medicine and physiology at the University of Maryland School of Medicine and director of its cardiopulmonary genomics program. “In this case, it seems that this genetic variation is a good thing, mimicking drugs that are frequently used to treat heart failure,” says Dr. Liggett.