Researchers in Australia and New Zealand have found genetic underpinnings for about a quarter of unexplained sudden cardiac deaths, the Guardian reports.
The University of Sydney's Christopher Semsarian and his colleagues conducted a prospective study of sudden cardiac death among people between the ages of 1 and 35 living in Australia and New Zealand, as they report in the New England Journal of Medicine. For about 40 percent of the 490 cases, autopsies that included toxicological and histological studies were unable to explain the cause of death. For 113 of these cases, the researchers obtained genetic material to analyze some 59 cardiac arrhythmia and cardiomyopathy genes.
For 27 percent of those unexplained cases of sudden cardiac death for which they had blood samples, Semsarian and his colleagues uncovered a clinically relevant mutation. For instance, they uncovered pathogenic and likely pathogenic variants within the RYR2, ANK2, and MYH7 genes, among others.
The researchers also performed clinical screening in about half the families in which an unexplained sudden cardiac death occurred, and a definitive diagnosis — such as of long-QT syndrome — was made in 12 of those families.
"If you work out the gene fault that caused the young person to die suddenly you can test the relatives of the individuals for that genetic mutation and if the relative has the same gene mutation then they are at risk of dying suddenly as well," Semsarian tells the Guardian. "In that case we would put them on treatment, so either medical therapies like beta-blockers or devices where we implant defibrillators inside the chest wall."