Download Discovery of new gene that causes sudden death in adolescents

PRESS RELEASE
Discovery of new gene that causes sudden death in adolescents
9 March 2017 | Cape Town | Medical researchers, through a global collaboration, have identified a new
gene that is a major cause of sudden death among young people and among athletes. The gene, called
CDH2, causes Arrhythmogenic Right Ventricle Cardiomyopathy (ARVC), a genetic disorder that
predisposes young people to cardiac arrest.
“This is probably the biggest breakthrough in South African cardiology since Dr Chris Barnard’s first heart
transplant”, said Professor Bongani Mayosi, Dean of the Faculty of Health Sciences at the University of
Cape Town (UCT). “This discovery is a first in the world - on our soil - and will permit the diagnosis and
possible targeted treatment of heart muscle disease in the future.”
According to country estimates, sudden cardiac death claims the lives of more than 5 young South Africans
per day. In Italy, amongst the whole population, about 50,000 people die suddenly every year. In young
people, like amongst South Africans, an inherited form of disease of the heart muscle (cardiomyopathy)
appears to have a prominent role in the cause of sudden death that is related to cardiac disease.
In ARVC, the heart muscle tissue is replaced by fatty and fibrous tissue. This process encourages the
development of an abnormal heart rhythm (cardiac arrhythmias) such as rapid heart rhythm or rapid and
erratic heart rhythm (ventricular fibrillation), that causes loss of consciousness and cardiac arrest. In the
case of ventricular fibrillation, without a ready device to shock the heart, it causes sudden death in a few
minutes.
The importance of the discovery is twofold, and has both scientific and clinical impact. On the one hand it
helps to clarify the genetic mechanisms underlying ARVC, contributing to a more complete identification of
the disease genes involved in cardiomyopathy. On the other, it makes possible the early detection of many
unsuspecting people who are affected by ARVC.
“When pioneering medical researchers make discoveries such as this, it enables us to innovate to find easy
ways to detect the gene or diagnose ARVC and find ways to prevent sudden death in young South Africans”
says Professor Glenda Gray, President & CEO of the South African Medical Research Council (SAMRC).
“This collaborative research is what we relentlessly seek to fund, because it directly translates into finding
ways to save lives in South Africa” Gray concluded.
Often the diagnostic clinical signs of the disease become clear only after many years. If a subject with
ARVC is a carrier of a mutation of the gene CDH2, which we have discovered, it means that the subject is
at a higher risk of cardiac disease. All people do carry the gene however, the mutation of the CDH2 gene
is the indicator that a subject is genetically affected and allows the need to start preventive strategies such
as lifestyle changes to ensure that the subject lives a healthy life. This may lead to a reduction of cases of
sudden death in patients with this mutation.
This discovery, published today in the prestigious journal Circulation: Cardiovascular Genetics, was made
from a South African family affected by ARVC and is as a result of an international collaboration which
began 15 years ago. Excluding all genetic causes so far known, Dr Crotti and Professor Peter Schwartz
of the Italian Auxologico Institute (Auxo) of Milan, sequenced all the coding regions of the genome in two
sick persons of the family.
The genetic mutation responsible for the disease in the family was narrowed down from more than 13,000
common genetic variants present in the two sick subjects. This is the CDH2 gene, responsible for the
production of Cadherin 2 or N-Cadherin, a key protein for normal adhesion between the cardiac cells. The
discovery of this gene has been validated by finding a second mutation on the same gene in another patient
with ARVC belonging to a different family. It was already known from previous studies that genetically
modified mice and in which this protein is absent in cardiac tend to have malignant ventricular arrhythmias
and sudden death.
Issued by:
Linda Rhoda
Dr Pierangelo Garzia
Aziel Gangerdine
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ENDS.