Heredity is the biological mechanism by which genetic information is transmitted from parent to child, determining inherited characteristics including physical traits, susceptibility to disease, and in some cases, specific medical conditions. Each person inherits roughly half of their genetic material from each biological parent, with variations in specific genes that can alter the function of proteins and cells.
In cardiology, hereditary factors are important in a range of conditions that can cause sudden cardiac arrest. Inherited cardiac conditions include hypertrophic cardiomyopathy (HCM), Brugada syndrome, long QT syndrome, arrhythmogenic right ventricular cardiomyopathy (ARVC), and dilated cardiomyopathy, among others. These conditions are typically inherited in an autosomal dominant pattern, meaning that a variant in one copy of the relevant gene is sufficient to cause the condition, and each child of an affected person has approximately a 50% chance of inheriting the same variant.
When a young person or someone without traditional risk factors suffers a sudden cardiac arrest or unexplained sudden death, genetic investigation is recommended. Molecular autopsy (genetic testing of a post-mortem blood sample) can identify a causative variant in around 25 to 35% of young sudden death cases. Living family members who have had a first-degree relative die suddenly or be diagnosed with an inherited cardiac condition are strongly advised to seek cardiology review and, where indicated, genetic testing through an inherited cardiac conditions clinic.
Hereditary cardiovascular risk also extends to the familial clustering of common risk factors such as high cholesterol (familial hypercholesterolaemia), hypertension, and coronary artery disease. A strong family history of premature heart disease should prompt earlier screening and more proactive risk factor management in other family members.
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