Heart rhythm disorders may be caused by various factors. Among these, genetics play a key role in a wide range of pathologies. Certain inherited abnormalities, passed down within families, can affect the structure and functioning of cardiac cells, thereby increasing the risk of developing potentially serious arrhythmias. Nowadays, the study of these genetic predispositions can be used to identify people at risk, to better understand the mechanisms of these diseases and to propose appropriate therapeutic care. Within this context, genetic testing is vital for the early detection of hereditary heart rhythm disorders, so as to be able to provide diagnostic, preventive and therapeutic options.
What is genetic testing?
Genetic testing is a series of medical tests carried out to analyze a patient’s DNA (deoxyribonucleic acid). These tests may concern only part of the genome, or the exons (1-2% of the genome) — or even the whole genome. The genome is a person’s entire set of genetic information, contained in each of the body’s cells in the form of chromosomes.
This testing can be used to identify genetic abnormalities or predispositions to certain diseases. In particular, it is used in the fields of oncology, neurology and cardiology.
How does genetic testing work?
DNA contains information for the development, functioning, growth and reproduction of each person. Human DNA contains 23 pairs of chromosomes, made up of around 20,000 to 25,000 genes. Genetic testing is used to analyze these genes, and to look for and identify any potential abnormalities that may explain certain dysfunctions.
Why have genetic testing?
The medical profession may prescribe genetic testing for several reasons.
First, risk assessment. These tests measure the probability of developing a hereditary disease, for example, or cardiovascular disease more specifically. This then makes it possible to adopt preventive measures, such as treatments, close monitoring or even a change in lifestyle.
Next, the diagnosis of hereditary diseases. This testing is sometimes key to diagnosing inherited conditions, especially when they are rare. Therefore, these tests are required for certain patients with heart failure, particularly cardiomyopathy.
Genetic testing can also help people who are considering becoming parents. What are the risks of transmitting a disease? How can these risks be approached? Genetic testing is a vital tool that is needed to make important decisions as the full facts will be known.
These tests can also be used to customize medical treatments to specific individuals (especially dose adjustments, choice of therapies) based on the genetic profile.
Lastly, this testing can be used to detect certain diseases at an early stage and to prevent them via close monitoring, treatments or even surgery in certain cases.
What happens during genetic testing?
Genetic testing may be prescribed by a general practitioner, after discussing the patient’s family history and specific medical history.
In general, genetic testing is done via a simple blood test.
However, it takes much longer to analyze. The doctor will only be able to give the results several weeks, or even several months later.
Is genetic testing painful?
No, in general, genetic testing is not more painful than a traditional blood test. These tests may be done using other methods, but they are still painless for the most part.
Is genetic testing always done via a blood test?
No, other tests may be used in some cases. For example, sometimes an amniotic fluid sample or cell samples from the future placenta are taken for a prenatal diagnosis. Saliva, skin cell or muscle cell samples may also be taken.
How are genetic tests interpreted?
A specialized laboratory will perform a bio-medical analysis on the patient’s DNA, to look for possible dysfunctions. The physician will then discuss the results with the patient in their office and may possibly refer them to specialists. Some patients may also be advised to inform their family members about the existence of a certain medical condition, so that they can also have genetic testing done.
What is cardiogenetics?
Over the past several decades, an approach to anticipating heart disease by studying genetics has been gaining increasing recognition.
In Bordeaux, the Liryc Institute works closely with CMARY (Bordeaux University Hospital), a Hereditary Heart Rhythm Disorder Reference Center. Coordinated by Dr. Frederic Sacher (Professor in Cardiology), the center’s multidisciplinary team cares for patients with hereditary heart rhythm disorders and patients at risk of sudden death.
The team has been organizing and standardizing the care of these patients in the Aquitaine region since the early 2000s. Family screenings for patients with hereditary heart rhythm disorders have also been set up, in particular through the introduction of joint cardiology and genetics consultations. Find out more
