Rare gene mutation linked to lower heart attack risk

Scientists have discovered several mutations in one gene that may safeguard a person from heart attacks.

The mutations in this specific gene, known as APOC3, have been found to keep triglycerides at levels lower than average, which could help researchers develop a new generation of drugs to prevent cardiac arrest and stroke among people who are at high risk.

The findings were just published in two related papers in the New England Journal of Medicine. The researchers from both teams -- one from University of Copenhagen and the other from Massachusetts General Hospital and the Broad Institute -- say these four mutations in the APOC3 gene lowered heart attack and stroke risk by approximately 40 percent.

Dr. David Agus told "CBS This Morning" that these findings are a breakthrough in research for heart disease prevention and could someday provide patients with an alternative to statins, the cholesterol maintenance drugs associated with a number of risk factors including muscular pain and liver damage.

"For the last 30 years the way we've treated heart disease is by lowering LDL, which we have called the 'bad cholesterol,'" Agus explained. The APOC3 gene "was meant to keep triglycerides up, and when it's mutated or turned off triglycerides go down and heart disease goes down pretty dramatically in these people. So we now have for the first time a new target to prevent or delay heart disease."

Heart attack remains the number one killer in the U.S. According to the Centers for Disease Control and Prevention, coronary heart disease is responsible for 1 out of every 4 deaths per year and kills a total of 600,000 Americans annually.

One of the studies, conducted by researchers at the Broad Institute at Massachusetts General Hospital, looked at the genetic makeup of 3,734 people. At least one APOC3 gene mutation was found in 1 out of 150 study participants. Individuals with mutations had plasma triglyceride levels that were 39 percent lower than non-carriers. Further, their HDL cholesterol levels -- the "good" kind -- were 22 percent higher, while their LDL cholesterol levels were 16 percent lower than those who did not have a mutation.

The other study from researchers in Copenhagen examined the APOC3 gene in 75,725 people who were then followed for 34 years. The researchers found those with mutations had a 44 percent lower amount of triglycerides and a 36 percent lower heart attack risk.

Too many triglycerides raise cholesterol levels and increase a person's risk for developing heart disease. The researchers say that normally this particular gene blocks the removal of lipids from the blood.

Normal levels of triglycerides is less than or equal to 150 micrograms per deciliter; high triglyceride levels are greater than 200 micrograms per deciliter.

Agus says that these findings reflect a similar study published in 2008 that looked at the same gene among a small sample of people in an Amish community.

All of this promising research has now led researchers to work on developing a drug that targets the APOC3 gene, turns off its function and thereby lowers triglyceride levels. "We've yet to see whether it prevents heart attacks, but there's certainly a lot of hope," Agus said.

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