"That doesn't mean African-Americans with heart failure need to be tested for the genetic variant to decide whether to take beta blockers," Dorn says. "Under the supervision of a cardiologist, beta blockers have very low risk but huge benefits, and I am comfortable prescribing them to any heart failure patients who do not have a specific contraindication to the drug."
"This is a step toward individualized therapy," Cresci says. "Medical research is working to identify many genetic variants that someday can ensure that patients receive the medications that are most appropriate for them. Right now, we know one variant that influences beta blocker efficacy, and we are continuing our research into this and other relevant genetic variants."
The human heart has two forms of GRK: GRK2 and GRK5. The researchers meticulously searched the DNA sequence of these genes in 96 people of European-American, African-American or Chinese descent to look for differences. They found most people, no matter their race, had exactly the same DNA sequence in GRK2 or GRK5. But there was one common variation in the DNA sequence, a variation called GRK5-Leu41, the variant that more than 40 percent of African-Americans have.
To determine the effect of the GRK5-Leu41 variant, the team studied the course of progression of heart failure in 375 African-American patients. They looked for survival time or time to heart transplant, comparing people with the variant to those without. Some of these patients were taking beta blockers and some were not.
In patients who did not take beta blockers, the researchers found that those with the variant lived almost twice as long as those with the more common version of the GRK5 gene. Beta blockers prolonged life to the same degree as the protective GRK5 variant, but did not further increase the already impro
|Contact: Gwen Ericson|
Washington University School of Medicine