From the University of Maryland School of Medicine, a large team of researchers recently looked into why a person with no apparent health problems dies from sudden cardiac death (SCD). Their study published in JAMA Cardiology found that roughly 20 % of unexplained cases involve genetics.
In the US, SCDs are expected, with between 180,000 to 450,000 occurring every year. In 50 to 75% of the cases, coronary heart disease is involved, but doctors are uncertain of the reasons in 30 to 40 % of cases. According to the team, most research on SCDs, such as in South Korea, Denmark, New Zealand, tend to focus on homogenous populations of people under age 35. One study based in New York investigated a racially diverse cohort but included several infants. Genetic components of SCD were looked at by these studies. According to studies, “No systematic comparison of the genetics underlying cases of unexplained SCD between adult White and African American descendants has ever been conducted.”
For two decades, the State of Maryland’s medical examiner’s office has been collecting data on SCDs, which gave the team rich data to pull over around 5000 such cases. Researchers looked at from that set of data 683 African American and white adults. In total, the DNA of 413 patients who died from unexplained SCD was genetically sequenced. Thirty-eight arrhythmia genes and 30 different cardiomyopathy genes.
Aloke Finn, Clinical associate professor of medicine and corresponding author, says, “Genetic screening isn’t routinely used in cardiology, and far too many patients still die suddenly from a heart condition without having any previously established risk factors. We need to do more for them.”
One of the significant findings was that many of the deceased carried the genetic variant for hypertrophic cardiomyopathy (HCM), which causes the heart’s muscle tissue to be abnormally thick. This clearly explains people with no heart disease experience sudden cardiac arrest. HCM is a common heart disorder. People with particular genetic variants are likelier to die from unexplained SCD earlier in life as compared to others who die from unexplained SCD. By identifying these genes, researchers hope this information could be used in future medical screenings.