Genetic analysis could provide more information in many cases, but blood samples are not collected routinely at the time of death, and DNA extracted from the tissues collected at autopsy is damaged because of the way they are fixed in formalin and paraffin-embedded.
‘Dried blood spots from new-born screening can help identify the cause of sudden cardiac death in the young people.’
Sweden researchers identified all 22 Swedish cases of SCD between 2000 and 2010 in people aged under 35 with a post-mortem diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC), an inherited disease of the heart muscle that affects approximately 1 in 1000 to 1 in 5000 individuals.
Using whole exome sequencing, they extracted DNA from DBS, post-mortem formalin-fixed paraffin-embedded (FFPE) heart tissue, and frozen blood samples of victims, where they existed.
Although the researchers found a lower yield of DNA from DBS compared with FFPE, all of the DBS samples passed quality control, compared to 62.5% of the FFPE samples. Their findings will be presented at the annual conference of the European Society of Human Genetics.
The quality of the results from DBS were similar to those from the frozen blood samples, and analysis showed clinically relevant genetic variants in 12 out of 19 families.
Researchers now intend to offer carrier testing to these relatives and follow them clinically. They will also apply the DBS molecular autopsy technique in a larger group of 903 SCD victims from SUDDY, the Swedish Sudden Cardiac Death of the Young cohort.
The sudden and often unexplained death of a young person is a devastating event for their families. Through the identification of relatives who are carriers and at risk of sudden cardiac death, this becomes a preventable outcome.
As this is a post-mortem study, we cannot be totally sure whether the arrhythmogenic syndromes identified were a contributing cause of death or an alternative diagnosis or an overlapping phenotype.
However, these findings provide valuable new knowledge about the biology of cardiomyopathies and enable better risk assessment and care in these cases.
Source: Medindia
