Why are some families more likely to have epilepsy than others?
Some types of epilepsy and seizures run in families. These include childhood absence epilepsy (CAE), juvenile myoclonic epilepsy (JME), photosensitive seizures, generalised epilepsy with febrile seizures plus (GEFS+) and focal seizures. However, it’s more common for families to have different types of epilepsy in them. So if your child does develop epilepsy, it may well be a different type to other family members.
A small number of children are born with specific changes in specific genes that cause them to develop epilepsy. Although genes are inherited from both parents, these parents don’t themselves have epilepsy. The gene changes are very specific and only affect that child.
Seizure types
CAE, JME and GEFS+ are all epilepsies that affect people within a certain age range. All the seizures in these types of epilepsy are generalised ones.
Some people who have temporal lobe epilepsy inherit this from their parents. Focal (partial) seizures are usual in temporal lobe epilepsy. It is thought that generalised seizures are more likely to be inherited than focal seizures. But recent research suggests that more focal seizures than previously thought can be inherited.
More information about different types of seizures is available from Epilepsy Action.
We all have something called a seizure threshold in our brain. A low seizure threshold seems to run in some families. People with a low seizure threshold are more likely to have seizures than people with a high seizure threshold. You might inherit a low seizure threshold.
Two to 3 in every 100 people with epilepsy have another medical condition that also causes epilepsy. The risk varies depending on what the other medical condition is. Tuberous sclerosis is a rare condition that is inherited. It causes non-cancerous tumours to develop in different parts of the body, including the brain. And it can cause other health conditions, including epilepsy, learning disabilities and autism. Eight or 9 in every 10 children born to a parent with tuberous sclerosis will develop epilepsy.
More information about tuberous sclerosis is available from the Tuberous Sclerosis Association.
Tel: 01332 290 734
Website: tuberous-sclerosis.org
What is the risk of my child inheriting epilepsy?
Each type of epilepsy has a different level of risk for being inherited. If your epilepsy isn’t part of another medical condition, your child’s risk of inheriting it is thought to be less than 15 in every 100. It also depends on how many other family members have epilepsy, the type of epilepsy they have, and the age it started.
Here is some information about the risks of a child developing epilepsy, when other family members have epilepsy.
Person in the family with epilepsy | Mother | Father | Mother and father | Other family members |
Risk of child developing epilepsy compared to childen without a family history | Higher | Slightly higher | Higher than if just the mother has epilepsy. But even then it is more likely the child will not develop epilepsy
| The more people with epilepsy there are in a family the higher is the risk that the child will inherit epilepsy |
Age at which parent developed epilepsy | Under 20 | 20 - 35 | Over 35 |
Risk of child developing epilepsy compared to childen without a family history | Higher | Slightly higher | The same |
To sum up
Research into epilepsy and inheritance is being carried out all the time. So, in time, we might find out more about how epilepsy is inherited. Here is what we understand so far:
- The risk that a child will inherit epilepsy depends on the type of epilepsy that is in the family, which family members have epilepsy, and how old they were when they developed it
- Some types of epilepsy have a higher risk of being inherited than other types
- Some people don’t inherit epilepsy itself, but they inherit a low seizure threshold
- Some children are born with changes to specific genes that cause them to develop epilepsy
- Other than children with tuberous sclerosis, fewer than 15 in every 100 children born to parents with epilepsy will inherit epilepsy
If you would like to see this information with references, visit the Advice and Information references section of our website. If you are unable to access the internet, please contact our Epilepsy Action Helpline freephone on 0808 800 5050.
This information has been produced under the terms of The Information Standard.
- Updated August 2015
- Currently under review
Epilepsy Action would like to thank Dr Rhys Thomas, Clinical Lecturer in Neurology, Morriston Hospital, Swansea, for his contribution to this information.
Dr Rhys Thomas has no conflict of interest to declare.
Comments: read the 4 comments or add yours
Comments
Hi
I spotted a Facebook post recently regarding a parent having to have a test to find out if they have epilepsy as their child has been diagnosed and having issues with chromosome 15. I didn't realise you could have a test to see if you are a carrier. What is this test? Myself and partner are thinking about children later on (only 22 & he's 25 at the moment) but his family does have epilepsy run in the family (auntie & cousins) his mum hasn't got it so it must have missed a generation but this could mean that Jake could potentially be a carrier (he has lots of head aches often.. same way I started out before being diagnosed or had seizures) If so we want to find out so we know what we want to do as my biggest worry is the usual 'what if I pass it On?' I am the only one in my family that I am aware off that has epilepsy. I've always been yes & no towards having children of my own and I think if we could get this test done for my partner this would settle me. Any guidance on this wouls be fantastic!
Hi Stephanie
Although some types of epilepsy have a genetic cause, at the moment there’s no single test that can tell someone if they are likely to develop epilepsy or pass it on to their children.
I’m not sure which facebook post you saw, but an abnormality in chromosome 15 has been linked to Angelman syndrome. This is a genetic disorder that can cause epilepsy. So if a child was diagnosed with Angelman syndrome, their parents might have genetic testing to see if they had an abnormality in chromosome 15. There are other genetic changes that have been linked to other types of epilepsy.
If you and your partner are worried that he could be a carrier of a gene that could cause epilepsy it would be best to speak to his family doctor. They might arrange a referral for genetic testing if they think it would be helpful. To be able to know what genetic change to look for, it’s likely that his family members who have epilepsy would need to be tested too.
Lots of parents with epilepsy worry about whether their children will also develop epilepsy. There’s no way of knowing for certain what will happen if you decide to have children. But most children born to parents with epilepsy don’t develop epilepsy themselves.
I hope this helps.
Grace
Epilepsy Action Helpline Team
My mother has grand mal epilepsy. Both my sister and I are not epileptic. My eldest daughter (7 years old) tends to 'zone out' a number of times a day, particularly when in school but the teachers just think she is daydreaming, this seems excessive daydreaming to me. I was curious if she may have a mild form of peti Mal? How could I go about finding out without putting her through too much?
Any help appreciated x
Hi Laura
As you will have seen there are some types of epilepsy which can be inherited.
So it is possible that your daughter could be having absence seizures. It is easy for absence seizures to go unnoticed for some time, exactly because they can look just like daydreaming.
If your GP thinks it might be absence seizures then they will refer your daughter to a paediatrician. The main test for epilepsy is an EEG. This does not hurt though it might be a bit uncomfortable.
If your daughter is possibly having absences then it would be good to have this diagnosed and treated sooner rather than later.
I hope that helps.
Regards
Cherry
Epilepsy Action Helpline Team