What remains of the deceased: DNA extracted to try and determine the cause of death. | IRM Zürich

When someone young dies suddenly and unexpectedly, it’s always a great shock to their family. Often, undiagnosed heart problems are the cause, but autopsies can’t always prove it. ‘Sudden unexplained death’ is the medical term when it affects people under 40. Researchers at the University of Zurich have been looking at the genes of the deceased in 34 such cases, and have encountered specific sequences of relevance to their investigations.

The team focussed their search on the two percent of DNA that store the blueprints for roughly 90,000 proteins. And in six cases, they indeed turned up genetic variants that are known for causing heart malfunctions. Defects in these genes can lead to structural changes in the heart (cardiomyopathy) and to cardiac arrhythmia.

The same team reached similar results last year when they investigated 161 cases of sudden infant death syndrome. This syndrome remains a mystery, and there are several factors that can have a considerable impact on the risk of death. For example, babies shouldn’t be placed on their front to sleep.

“These new results make it possible for us to examine close relatives of the deceased to see if they have the same gene defects”, says lead author Cordula Haas. Some 80 percent of cases of ‘sudden unexplained death’ do remain true to their name, however. The researchers suspect that there are other gene variants that could cause similar problems but that have not yet been identified. It’s these genes that they want to track down to further the course of their research.