New electrical test to screen individuals at risk of sudden cardiac arrest

New research from the Victor Chang Heart Research Institute will allow families around the world to discover whether they carry genetic mutations that cause sudden cardiac arrest – a condition that kills nine out of 10 victims.

Researchers at the institute have developed a new electrical test that can screen for hundreds of genetic mutations to identify the exact mutations that damage the heart of those with inherited heart disorder syndromes, which can cause sudden death.

This breakthrough is a giant step forward in the accuracy and accuracy of genetic testing that has profound implications not only for inherited heart disorders but also for a wide range of neurological conditions and muscle and kidney diseases.

Professor Jamie Vandenberg, who led the research published in two consecutive papers in The American Journal of Human GeneticsPrimarily, young people with healthy hearts die from inherited heart disorders, and although this number is small, the consequences are long-term.

“When a person dies young, in the prime of life, it is so much more than the death of one individual. The impact is felt on family and friends and lasts forever.

Being able to identify these dangerous mutations will prevent people from dying of sudden cardiac arrest and ensure more people are treated for this life-threatening disorder, says author Dr Chai Ann Ng, of the Victor Chang Heart Research Institute.

If you can isolate the mutation and identify those at risk, there are lifestyle changes people can make, in addition to taking beta blockers or even using a defibrillator. Family members can also test themselves as well.


Genetic sequencing has revealed that each of us contains a wide range of genetic variants, but we weren’t always able to tell if these variants were dangerous or not, just that they are different.


So when the genes are currently being tested, the clinical genetics lab might tell the patient, there is a variant, but we don’t know if it increases your risk of cardiac arrest. This creates a great deal of anxiety not only for the patient but for the rest of the family who may have inherited the mutation as well. We can now remove the uncertainty which is a major development.”


Dr. Chai An Ng, Victor Chang Heart Research Institute

Key stats

  • Hereditary arrhythmias are found in more than half of all initially unexplained cases of sudden cardiac death in young adults.
  • About 20,000 Australians suffer cardiac arrest outside hospital each year. Only 10% of cardiac arrests survive outside the hospital.

Professor Vandenberg’s team studied variants in the genes that encode ion channels, which are proteins that control the movement of electrical signals between cells. The majority of genetic disorders that increase the risk of sudden cardiac arrest are caused by these mutations.

Main results

  • In the first study, they developed a rapid and accurate electrical test that evaluates variants in the ion channel gene that cause an inherited arrhythmia condition called Long QT syndrome type 2. They are now classifying all known variants in this gene to determine which are benign and dangerous and the results will be uploaded to a genetic database Giant will be accessible to doctors all over the world.
  • The test they developed could easily be adapted to test for other ion channel genes – not just those linked to sudden cardiac arrest but a wide range of other diseases that include neurological, kidney and muscle disorders.
  • In the second paper, Professor Vandenberg and his team collaborated with Dr. Kroenke at Vanderbilt University Medical Center to develop a new method based on high-throughput genome sequencing technology. This will enable them to assess the impact of each potential missense variant in KCNH2, which amounts to approximately 22,000 variants, within one to two years.

Effect

Professor Vandenberg says: “Hopefully within five years, once anyone has done gene testing, or sequenced their genome, they will immediately find out whether their variant is dangerous.

“It is incredible to think that 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 from genetic disorders.

“In the short term, heart patients at risk of sudden death are the ones who stand to benefit the most. But in the long term, the research could be adapted to assess which of the 400 different ion channel genes in the human genome are associated with a wide range of neurological disorders and muscle and kidney problems.”

source:

Victor Chang Heart Research Institute

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