Genetic Heart Disease

Everyone’s journey with a genetic heart disease is different. Some people may not realise they have an inherited heart condition until they start to show signs of heart issues, such as chest discomfort, palpitations, shortness of breath or blackouts. Some individuals have no symptoms before they suddenly pass away. Others still may show symptoms and signs from early childhood or even infancy.

The only surefire way to know if you have a genetic heart disease is to work with a service to confirm a diagnosis. You may be triggered to start this work by an event in your family’s health, such as the death of an otherwise healthy young person, increasing suspicious symptoms in yourself or another family member, or just a concern that you have an inherited heart condition. From there, you can discuss your concerns with your physician, before seeing someone who specialises in inherited heart diseases. 

As part of this evaluation, you may also undergo genetic testing. This is when you provide a small genetic sample, such as saliva or blood, to be tested for the presence of damaging (pathogenic) genetic mutations. Genetic testing is often the best way to confirm a diagnosis of a genetic heart condition but other tests can help reveal the condition of your heart and allow for effective treatment and management plans to be set out.

If a parent, regardless of gender, is a carrier of an inheritable heart condition or is affected by the heart condition, there is the possibility that the child may inherit the condition (or become a carrier themselves). The chances of inheriting the condition are not related to gender but to how the genetic mutation increases the risk of that condition.

Genetic heart disease mutations can be inherited as dominant or recessive problems. In autosomal dominant conditions, only one copy of a gene mutation that causes a heart condition is needed in the body for the mutation to cause the condition. Therefore, conditions like Marfan syndrome and hypertrophic cardiomyopathy only require one parent to have the condition for there to be a 50% chance of their child inheriting the heart problem. 

Conversely, autosomal recessive conditions are those that require a complete pair of the mutation, meaning that a child has to inherit one faulty copy of the gene from each parent. These conditions are far rarer, because they require both parents to be carrying the condition. Because of how genetics work, with every child inheriting a combination of pairs of genes from their parents (e.g. both genes of a pair from their father, or one part of the pair from either parent, and so on), the likelihood of an autosomal recessive genetic heart disease being inherited is less (at about 25%). So, autosomal recessive conditions like homozygous familial hypercholesterolemia or the Jervell and Lange-Nielsen variant of long QT syndrome are much less common than autosomal dominant heart conditions.

It is also possible for a child to spontaneously develop the genetic mutation that causes a genetic heart disease at conception. This is called a ‘de novo’ mutation.

Regardless of what led to the mutations occurring, a child with the relevant genetic mutation is at risk of developing the genetic heart disease from birth. It is also impossible to change or remove the mutation, and the likelihood of the child developing the disease can never be entirely done away with. What can, instead, be done is proactive checks and testing to achieve an early diagnosis. This is vital to improving life expectancy and quality of life for the person with the mutation.