Heart smart

Heart smart

June 9, 2010

The golden dream of modern genomics — DNA tests that can predict who will get potentially fatal conditions, and procedures to mitigate their lethal effects — is being realized as the result of groundbreaking research into the genetics of an isolated group of Newfoundlanders.

Memorial University scientists led by molecular biologist Terry-Lynn Young have discovered a genetic mutation that causes arrhythmogenic right ventricular cardiomyopathy (ARVC) type 5. This disease is infamous in the non-medical world as the cause of sudden heart failure in previously healthy athletes who have just competed in a strenuous sport. The prevalence of the disease is difficult for researchers to define, but overall, they estimate it afflicts between 1 in 1,000 and 1 in 5,000 people, and has a strong genetic link.

In the 1980s, researchers found that the mutation had been passed on through eight generations of an extended Newfoundland outport family.

Two years ago, a study of 15 families in Newfoundland and Labrador allowed Young and her group to locate the exact genetic mutation that causes this version of ARVC. They were also able to show that while nearly everyone with the defect eventually develops the condition, there is a dramatic difference in its effect on men and women. Half of all untreated men and five percent of women die before the age of 40. 

The good news was that implanting a type of pacemaker known as a defibrillator could get the heart beating again after ARVC-related heart failure. This coincidence of diagnosis and treatment led to the almost immediate application of their findings.
The Genesis Group, Memorial’s commercialization arm, has licensed the right to test for the mutation to Newfound Genomics in St. John’s and PGxHealth, a division of Clinical Data, in Newton, Massachusetts. The Newfoundland company will soon be providing tests for Eastern Canada and parts of the Middle East, while the American company has already begun marketing the test to the rest of the world.

Simultaneously, people who test positive for the mutation in Newfoundland have begun to have defibrillators implanted before they exhibit any manifestations of the disease. In a significant number of cases, this translates into surviving the heart failures that previously would have killed them.