Families all over the world will be able to find out if they have genetic abnormalities that cause sudden cardiac arrest, which kills 9 out of 10 victims, thanks to new research from the Victor Chang Cardiac Research Institute.
The Institute’s researchers have created a novel electrical test that can screen hundreds of gene mutations to find the particular mutations that are detrimental to the heart for patients suffering from inherited heart disease syndromes, which can result in sudden death.
The result represents a huge leap forward in the accuracy and precision of genetic testing, with far-reaching implications for a wide range of neurological problems, as well as muscular and renal diseases.
“It’s primarily young people with otherwise healthy hearts that die from these inherited heart disorders and even though that number is small, the consequences are long-lasting,” explains Professor Jamie Vandenberg, the study lead.
Dr. Chai-Ann Ng of the Victor Chang Cardiac Research Institute, a co-author, believes that being able to identify these harmful mutations would save lives and ensure that more patients are treated for this life-threatening illness.
“If you can isolate the mutation and identify those at risk, there are lifestyle changes people can make, as well as taking beta-blockers or even using a defibrillator. Family members can also get themselves tested too,” Dr. Ng adds.
“Genetic sequencing has revealed that all of us contain a vast array of genetic variants, but we have not always been able to pinpoint if these variants are dangerous or not, only that they are different.”
“So when genes are currently tested, the clinical genetics lab may tell the patient, There’s a variant, but we don’t know whether it raises your risk of cardiac arrest. That creates a huge amount of anxiety not just for the patient but also for the rest of the family who may also have inherited the mutation. We can now remove that uncertainty which is a big development.”
Professor Vandenberg’s team looked at gene variants that code for ion channels, which are proteins that regulate the flow of electrical signals between cells. These mutations are responsible for the majority of genetic abnormalities that raise the risk of sudden cardiac arrest.
In the first study, the researchers developed a rapid and accurate electrical test for assessing variations in an ion channel gene that cause Long QT syndrome type 2, an inherited heart arrhythmia disorder. They are currently classifying all known mutations in this gene to identify which are benign and which are hazardous, and will upload the results to a global genetic database accessible to clinicians.
The test they devised can be simply extended to examine various ion channel genes, not just those linked to sudden cardiac arrest, but also those linked to neurological, renal, and muscular illnesses.
In the second study, Professor Vandenberg and his team teamed with Dr. Kroncke from the Vanderbilt University Medical Center to develop a new technique based on high throughput genome sequencing technology. Within one to two years, they will be able to examine the impact of every potential missense variant in KCNH2, which is estimated to be over 22,000 variants.
The team hopes “that within five years, as soon as anyone gets their gene testing done, or their genomes sequenced, they will immediately find out if their variant is dangerous,” says Professor Vandenberg.
“It’s incredible to think we will be able to screen family members not just across Australia but anywhere in the world and give them a diagnosis. Ultimately, this genetic database will reduce the number of cardiac arrests and deaths caused by genetic disorders .”
Cardiology patients who are at high risk of sudden death will benefit the most in the short term. However, in the long run, the discovery might be applied to any of the approximately 400 distinct ion channel genes found in the human genome, which are linked to a variety of neurological, muscular, and kidney ailments.
Image Credit: Getty