Discovery Of 'Heart Attack Gene' Adds Insight Into Risk Factors 

Healthy Lifestyle Still Recommended

A gene linked to coronary heart disease in humans recently was discovered by researchers and reported in the journal Science.

Now that scientists have identified the first gene mutation responsible for heart attacks, physicians eventually will be able to use this additional tool to help determine a patient's risk for heart disease.

Although the mutation has only been isolated in one family with roots in Iowa, the finding may shed light on the genetic pathways involved in early coronary artery disease and heart attacks, researchers say.

It also offers a new risk factor to consider, and a way to decide who needs to be extra vigilant about heart health.

"Until we have gene therapy, we are left with getting more aggressive with risk factors, isolating who is at higher risk and trying to change the course of the disease," says Dr. Daniel Fisher, a clinical assistant professor of medicine at New York University School of Medicine. "This is just something else that we're going to say let's get more aggressive."

The role of genetics in coronary disease is difficult to untangle because it is a considered a late-onset disease, experts say.

"By the time you find somebody, the parents have already died and the children are too young to have had the disease, which is critical to being able to do the work," says Dr. Eric J. Topol, senior author of the new study and chairman of the department of cardiovascular medicine at the Cleveland Clinic.

Experts Look for Risk Factors

The study started when Dr. Topol met with a heart attack patient at the Cleveland Clinic. During that first consultation, the man explained that he had 10 siblings, nine of whom had had heart attacks.

"That was a pretty strong signal" that there was a genetic link, Dr. Topol says.

Despite the high incidence of heart attacks in the family, none of its members had high cholesterol levels, which are extremely common in heart attack patients.

"Most people who have a heart attack have abnormal cholesterol, so it had to be something more penetrating and important than cholesterol to explain the disease," Dr. Topol says.

"It" turned out to be cracks in an arterial wall.

When the researchers did a genetic analysis of 13 family members (nine of whom had had a heart attack), they identified a region on chromosome 15 that includes a gene thought to be involved in blood vessel development.

The researchers discovered that family members with heart disease all carried a mutated version of the gene MEF2A. Those without the disease did not have the mutation.

The mutated version of the gene MEF2A "at birth sets up an artery wall that is not intact and then predisposes the person to a heart attack," Dr. Topol explains.

"It's a 100 percent risk," Dr. Topol says. "It's a pre-committed path to a heart attack." The heart attack usually occurs in men age 45 and over and in women age 50 and over.

Healthy Lifestyle May Stall Risk from Gene

What researchers do not yet know is how important environment factors are in relationship with a genetic mutation.

Experts are interested in knowing if altering environmental factors could stave off a heart attack in those with the genetic mutation.

"We know there is a defect in the artery wall, and if someone doesn't have the risk factors, they may still get this disease but it should be deferred substantially" by pursuing a healthy lifestyle, Dr. Topol says. "It is pretty unlikely that they could ward it off completely."

Since that first family member arrived in Dr. Topol's examining room, some 250 family members have been studied and given their genetic information. And the number keeps growing.

Having this information "changes everything," Dr. Topol says. "Now to be told you do or don't have this gene is a whole different story. It's much more definitive.

"If you do have this gene, many have a long way to go to turn around that risk," Dr. Topol explains. "And in the ones who don't have the gene, it's a tremendous amount of mental relief."

"Hopefully this [heart attack risk] can be changed at the earliest age," Dr. Topol says. "This is a disease that takes at least 20 to 30 years to incubate, so if you can start early, it's remarkable how much you can do."

Always consult your physician for more information.

Online Resources  

American Heart Association

Centers for Disease Control and Prevention (CDC) 

HealthierUS.Gov

National Heart, Lung, and Blood Institute (NHLBI) 

National Institutes of Health (NIH)

January 2004

Discovery Of 'Heart Attack Gene' Adds Insight Into Risk Factors

Experts Look for Risk Factors

Healthy Lifestyle May Stall Risk from Gene

Tissue-engineered Valves Give Diseased Hearts New Life

Online Resources

Find a St. John's Mercy Physician

In Other News About Your Heart Health:

Tissue-engineered Valves Give Diseased Hearts New Life

Heart valves engineered from patients’ own tissue may offer a new treatment for valvular heart disease, according to a press statement from researchers at the American Heart Association’s Scientific Sessions.

“Using this tissue-engineered valve overcomes many of the problems with mechanical or donor valves because it is a living structure from the patient’s own tissue, and so it does not cause an immunological reaction,” says Dr. Pascal M. Dohmen, head of tissue engineering research and staff surgeon of the department of cardiovascular surgery at Charité Hospital in Berlin, Germany.

Dr. Dohmen and colleagues presented data on the first 23 patients to receive tissue-engineered pulmonary valves in the heart, a procedure still considered experimental.

The patients, whose average age was 44, had aortic valve disease.  The aortic valve connects the heart’s left ventricle with the aorta, the main artery that distributes blood throughout the body. A diseased valve may either open or close improperly, and pressure can build in the ventricle, injuring the heart.

Physicians can treat the condition with medications or by surgically replacing the patient’s aortic valve with a donor valve, a mechanical valve, or the patient’s pulmonary valve. The pulmonary valve is between the right ventricle and the pulmonary artery. 

In a surgical “swap” called the Ross procedure, the abnormal aortic valve is replaced with the pulmonary valve, and the pulmonary valve is replaced with a donor valve.

Dr. Dohmen engineered a new pulmonary valve from the patients’ own cells. The surgical team implanted the patients’ healthy pulmonary valve into the aortic position. Then the tissue-engineered valve was implanted in the right ventricular outflow tract, where the pulmonary valve originally was.

With up to three years of follow-up, the engineered valve’s performance was “excellent,” Dr. Dohmen reports. 

Echocardiography showed that the valves were functioning normally; the valve leaflets or flaps appeared smooth and pliable, and showed no signs of calcification.

Always consult your physician for more information.