Can Epileptic Seizure Disorder Be Inherited From A Parent?

Epilepsy is a state of an enduring predisposition to have recurrent epileptic seizures. You are considered to have epilepsy if you have a diagnosis of epilepsy syndrome or more than two unprovoked seizures occurring more than a day apart.

Epilepsy currently affects about 50 million people¹ worldwide. Genetics is known to contribute to the development of this disorder. 

Can epilepsy be inherited?

Several factors can cause epilepsy, including infections, autoimmune and metabolic problems, or spontaneous mutations (changes to the DNA of a single gene, multiple genes, or a chromosome). 

The International League Against Epilepsy has listed genetics as one of the six classifications of epilepsy. About one in three² people with epilepsy have a family member with the condition. It can be inherited from one or both parents. Some studies³ have found that epilepsy is more likely to be passed down from the mother than the father. 

Even if someone does have one parent with an inheritable form of epilepsy, it doesn’t necessarily mean that person will inherit the gene. If both parents have a genetic form of epilepsy, it increases the chance of the gene is being inherited, but it’s still not a 100% chance.

Additionally, if a parent’s epilepsy was caused by another incident (such as a brain injury), this won’t be inherited because it has nothing to do with their DNA. 

What types of epilepsy are inherited?

Genetic generalized epilepsy, previously known as idiopathic generalized epilepsy,⁴ is a group of epileptic disorders that often have a genetic link. 

Generalized epilepsy describes seizures that originate at a point within or rapidly engage bilateral networks of the brain. They can include the whole cortex but do not have to and can be asymmetrical.

The inheritable types of genetic generalized epilepsy include:

Juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) is the most common type of genetic generalized epilepsy. It usually begins in adolescence and lasts throughout adulthood, albeit with a reduced frequency of seizures.

JME is classified by one or more of three seizure types: myoclonic jerks, generalized tonic-clonic seizures, and absence seizures. However, the hallmark is myoclonic jerks that are most frequent upon the first hour of awakening, typically as isolated jerks involving both arms.

The genetics behind JME is not fully understood, but a polygenic or multifactorial mechanism is most likely. Some JME cases are sporadic, others occur in families, and some are inherited in an autosomal dominant pattern, which means that only one parent needs to pass on the mutation for the child to inherit it. 

Childhood absence epilepsy

Childhood absence epilepsy is a common generalized epilepsy with a presumed genetic cause that usually begins in otherwise healthy school-aged children. It presents with typical absence seizures, marked by sudden and profound consciousness impairment with loss of body tone.

Twin studies, as well as family studies, indicate a genetic cause with a 17% risk of typical absence seizures in first-degree relatives of patients with childhood absence epilepsy. However, a clear single gene defect has yet to be elucidated.

Juvenile absence epilepsy

Juvenile absence epilepsy is another type of generalized epilepsy characterized by typical absence seizures like childhood absence epilepsy. However, it usually arises with a later peak age of onset of 10–12 years of age. 

Other differentiating factors from childhood absence seizures include myoclonic seizures in about 20% of the patients and a higher incidence of generalized tonic-clonic seizures, which is uncommon in childhood absence seizures. 

Although it’s unknown if there’s a genetic component, studies have demonstrated that about 40% of patients with juvenile absence epilepsy have parental consanguinity, and the same percentage has a family history of epilepsy.

Epilepsy with generalized tonic-clonic seizures alone

A generalized tonic-clonic seizure is the most common seizure type. It represents a loss of consciousness and a phasic tonic stiffening of the limbs, followed by repetitive clonic jerking. 

Patients who have epilepsy with generalized tonic-clonic seizures alone present exclusively with them; the typical age of onset is around adolescence. 

Although the exact genetic underpinnings have yet to be elucidated, there is strong evidence from family and twin concordance studies of heritable etiology. This type of epilepsy is considered the summed final effect of multiple gene abnormalities, variations, and additional environmental contributions.

In addition to genetic generalized epilepsy, some other types of epilepsy that can be inherited include:

Sleep-related hypermotor epilepsy

Sleep-related hypermotor epilepsy (previously known as nocturnal frontal lobe epilepsy) is a rare form of epilepsy that arises in late adolescence. It causes seizures linked to sleep that are hypermotor, and brief with rapid on- or offset. 

One type of sleep-related hypermotor epilepsy is caused by an autosomal dominant mutation in the cholinergic system genes. One of the most common mutations in this context is on the gene CHRNA4 and can inhibit a specific receptor in cells. 

This receptor (called that because it receives chemical signals) regulates chemical activity between nerve cells. 

Benign familial neonatal epilepsy

Benign familial neonatal epilepsy occurs within the first seven days of life. These seizures occur in term or late preterm infants after uneventful pregnancies and deliveries, with typically no family histories of seizures and in the context of normal neurologic examinations.

The most frequent seizure type in this context is unifocal clonic, sometimes with apnea. No generalized tonic seizures have been observed in this context.

This type of epilepsy can be caused by a few mutations inherited in an autosomal dominant pattern, typically on the KCNQ2 gene. However, some infants have also been found to have de novo pathogenic variants of the same gene.

Genetic epilepsy with febrile seizures plus 

Some patients have a propensity for febrile seizures, an early manifestation of genetic epilepsy with febrile seizures plus. 

This rare form of epilepsy is identified with febrile seizures that continue beyond six years of age and afebrile tonic-clonic seizures. This epilepsy typically starts in adolescence but can continue into adulthood. 

Genetic mutations have been identified as the etiology of genetic epilepsy with febrile seizures plus, and almost all in an autosomal dominant inheritance pattern. Interestingly, some family members who inherit these mutations may have nonfebrile seizures, while others will have the full scope of the syndrome depending on the gene. 

Most genes associated with genetic epilepsy with febrile seizures plus have been in either receptors or voltage-gated sodium channels.

Focal epilepsies

Focal epilepsies cause seizures that occur on one side of the brain. Several genetic epilepsy syndromes present with focal epilepsies, such as autosomal dominant lateral temporal epilepsy or familial temporal lobe epilepsies.

What causes genetic epilepsy?

Genetic epilepsy is caused by mutations. Hundreds of genes with different functions can have mutations associated with epilepsy. 

For example, mutations can cause:

• Problems with the structure and function of ion channels 

• Changes to the release and uptake of neurotransmitters (chemical messengers that send information between nerve cells) 

• Imbalances in excitatory nerve cells (those that increase the chances of a neuron becoming active) and inhibitory nerve cells (those that inhibit other neurons from propagating electrical signals)

• Mutations in the receptors (receivers on a cell membrane) and transporters (carriers across a cell membrane) in cells 

Usually, more than one gene is responsible for causing epilepsy in an individual. 

Often, epilepsy is caused by both genetic and environmental factors that interact with each other. When someone inherits a mutation or mutations, it puts them at a greater risk of developing epilepsy when exposed to specific environmental conditions, such as if the person receives a brain injury or is febrile. 

It’s less common for someone to have epilepsy solely caused by a single inherited mutation than for someone who has several mutations and environmental factors interacting with each other.

Is genetic epilepsy curable?

Epilepsy can’t be cured. However, someone with epilepsy can manage their condition with the following:

• Anti-seizure medications

• A high-fat, low-carbohydrate diet (a keto diet) dependent on the epilepsy type

• Surgery to remove the area of the brain that causes the seizure

• Vagus nerve stimulation, which uses a device to send regular bursts of electrical impulses to your brain through the vagus nerve, which extends from the brain to the abdomen 

The lowdown

Some epilepsies have a known genetic link, where mutations are passed down from parent to child. 

Although the exact mechanism of inheritance is complex and unknown, in many cases, interactions between environmental factors and the inherited mutation lead to someone developing epilepsy. 

Frequently asked questions 

Below are some of the frequently asked questions about the inheritance of epilepsy. 

How common is genetic epilepsy? 

Genetics is responsible for around 70–80%¹ of epilepsy cases. However, for most people, these inherited genetic factors interact with environmental factors to cause epilepsy. A single mutation can rarely cause epilepsy on its own. 

How do I know if my epilepsy is genetic?

It’s difficult to determine whether someone’s epilepsy is genetic because the way that it’s inherited is complex. Genetic testing has been developed for a few rare types of epilepsy, which can help determine whether those specific types are hereditary.