July 1, 2022

Is epilepsy genetic?

About Epilepsy

Is epilepsy genetic? Read our blog to find out about the ways genes are linked to epilepsy and what that means for your diagnosis

Finding the root cause of your seizures can help you understand why they’re happening - and give an explanation of where they come from. It is well known that many people have genetic epilepsy, which is when their seizure disorder is caused by specific mutations in their genes (the instructions that tell your body how to develop).

But the epilepsy genetic link is not always clear cut. While there are certain genes that appear to ‘cause’ epilepsy, we’re still not exactly sure how it works for most people.

So, what is the genetic cause of epilepsy and how does this interact with other factors that might lead to seizures?

A smiling family with genetic epilepsy

First up: what is a gene?

To understand the epilepsy genetic link, it's useful to get a reminder of what genes are. Genes can be described as ‘instructions’ that are passed from parents to children and contain all the information required to ‘tell’ the child’s body how to grow. From the color of your hair, to the shape of your face, your genes contain ‘code’ that tells your body how to grow and the physical traits that make you unique. Humans have between 20,000 and 25,000 genes.

Is epilepsy genetic?

Sometimes, yes. Defining exactly what percentage of epilepsy is genetic can be difficult, but it is generally believed that between 30% and 40% of epilepsy has a genetic cause. This means that the instructions contained in the person’s genes make their brain behave in a way that causes epileptic seizures. The epilepsy genetics link is a complex one, and it is not always straightforward.

It is also important to remember that genes are not the only cause of epilepsy. People can ‘acquire’ epilepsy - often after something like a brain injury, a stroke or a tumor. There are also many people whose seizures have no known cause.

Recommended: Why do people get epilepsy?

Here are some of the ways genes can cause epilepsy.

  • Direct genetic epilepsy

Some people’s epilepsy has a direct genetic cause. They might inherit a gene or a collection of genes from their parents that means that they will have epilepsy. Studies indicate that there are 84 genes that directly cause epilepsy syndromes. For example, mutations to the SCN1A gene are known to cause Dravet Syndrome

  • Genes associated with epilepsy

There are also several hundred genes that are associated with epilepsy, which do not always directly cause it. Sometimes, people may have several of these genes which makes it more likely that they’ll develop epilepsy. But other factors also come into play, including the environment they grow up in.

  • ‘De novo’ epilepsy genetics

All living things have genes which can mutate - which means they change randomly. Sometimes people have what is called a de novo gene mutation which causes them to develop epilepsy. In this case, the genetic mutation that causes epilepsy is new – they didn’t inherit it from their family.

  • Other conditions that affect the brain

Some people have genetic conditions that cause gradual changes to the structure of their brains, including things like tuberous sclerosis and neurofibromatosis. These conditions cause  growths to appear in their brains or nervous systems. These growths may then cause epilepsy if they interfere with normal brain activity.

Epilepsy genetic testing

Over the last three decades there have been major scientific advances in epilepsy genetic testing. Researchers have identified many of the genes that are associated with epilepsy and there are numerous ongoing studies which aim to understand the link between genes and seizure disorders. In future, it may be possible to do tests to identify the exact gene which is causing a person’s seizures.

Genes and drug resistant epilepsy

About a third of people with epilepsy find that medication does not help prevent their seizures. This can be deeply frustrating. However, new research seems to suggest that, for some people at least, there could be a genetic explanation. We are still not sure exactly how this epilepsy genetic link works, but future research could lead to new treatments.

Related: Managing seizure medication side effects

Your epilepsy and genetics

To learn more about the genes that might be a factor in your epilepsy, speak with your treatment team – they can explain the specific causes of your seizures.

The field of genetic epilepsy research is currently growing, and there are plenty of scientific studies happening all the time. If you'd be interested in participating in epilepsy genetic testing studies - and potentially help scientists to understand more about how our genes can cause seizures - speak with your doctor. They may be able to refer you to researchers.