Genetics is often key to treatment

Just as some people may be genetically programmed to heart disease, the answer to why people respond differently to the same treatment may be genetic. Understanding a body's genetic secrets may be key to both prevention and selecting treatments.

"Obviously, there are some very inherited forms of heart disease that clearly travel in families," says John F. Carlquist, Ph.D., co-director of LDS Hospital cardiovascular research. "Most heart disease has a familial pattern, and that's one of the major risk factors for having heart disease."

The extent to which the genetic predisposition works with the environment and lifestyle choices such as smoking is not well understood, he says. "But you could probably override your genetic predisposition with a healthy lifestyle. You could also override your protective factors with an unhealthy lifestyle."

The genetics of heart disease is the topic of tomorrow's Deseret Morning News/Intermountain Healthcare Hotline. From 10 a.m. to noon, Carlquist and Benjamin D. Horne, director of cardiovascular and genetic epidemiology at LDS Hospital, will take phoned-in questions.

Most heart-disease patients benefit from medications commonly used to treat their conditions. But there are always some who don't respond to a given medication and some who suffer an adverse event because of that medication — which is true for other diseases, as well. So researchers are trying to find genetic causes to why people don't respond or respond poorly.

Carlquist uses the example of Vioxx, which is a blessing to many people with conditions such as arthritis because the drug reduces inflammation and pain without creating stomach problems. But a subgroup of patients had heart problems as a result of taking Vioxx.

Had doctors been able to determine before treatment who would fall into which group, those reactions might have been avoided, Carlquist says. Now the Food and Drug Administration is "looking seriously at what sort of genetic information should be provided" when drug-trial data is submitted, he says.

LDS Hospital is tackling the same question with a blood thinner often prescribed for people with heart disease. Coumadin (warfarin) dosage must be tightly controlled and regular testing done to see how fast the blood coagulates in order to get the dose right.

Researchers elsewhere have identified a couple of genes that seem most relevant to that. Now doctors and researchers at LDS Hospital are studying how those genes influence Coumadin metabolism. "We can predict the stable dose based on those two genes," Carlquist says.