Genetic Link to Sudden Cardiac Death

Sudden cardiac death doesn't mess around. It's as unexpected as it sounds with few clues about who or when it will strike. But a genetic link suggests some cases may be predictable.

Johns Hopkins University School of Medicine researchers have identified a genetic risk factor that can double a person's risk of a heart failure.

Ask a physician about genetic tests for sudden cardiac death.

The variation in a genome's DNA sequence they discovered is called BAZ2B locus. It contains three previously unknown genes that play a role in cardiac biology. Researchers said the finding could help it be prevented in those most at risk. Thousands die from sudden cardiac death each year.

Dan Arking, lead author of the study and an associate professor in the McKusick-Nathans Institute of Genetic Medicine at Johns Hopkins University School of Medicine, said that those who inherit the gene from each parent would have a sudden cardiac death risk that is four times greater than someone without the gene.

Scientists do not yet have enough information to proceed with clinical tests or therapies. They must first pinpoint the key player of the three genes identified, and identify how that gene's function is compromised, likely using model organisms.

In identifying the variant, researchers combined five separate genome-wide association studies to examine 3 billion DNA sequence pairs in 1,283 individuals with European ancestry who experienced sudden cardiac death.

They also studied the sequence pairs of 20,000 individuals who did not suffer from sudden cardiac death. In confirming the gene, investigators followed up with an additional 3,119 sudden cardiac death cases, and 11,146 without the syndrome.

Simply collecting an ample amount of DNA samples was challenging for researchers because most people do not have symptoms to suggest they might be at risk for sudden cardiac death. Only about 10 percent survive.

Arking noted that just because a person carries the gene doesn't mean sudden death will occur since other risk factors such as diabetes and heart attack also play a role.

The study was published in PLoS Genetics.