Is Epilepsy Genetic?

About half of the time, the cause of epilepsy is unable to be identified. When a cause can't be found, it is called cryptogenic epilepsy. For the other half of epilepsy cases, the causes may be more easily identifiable, such as head trauma or a known genetic syndrome.

Read on to learn more about how genetics can play a role in the development and treatment of epilepsy.

Genetics and Epilepsy

Genetic epilepsy means that the person has one or more genes that increase the likelihood of developing seizures.

Often in idiopathic generalized epilepsy (also called genetic generalized epilepsy), these abnormal genes only increase the risk of seizures by a small amount individually, but if several of these genes are present, epilepsy becomes more likely.

Idiopathic epilepsies include:

• Childhood absence epilepsy
• Juvenile absence epilepsy
• Juvenile myoclonic epilepsy
• Epilepsy with generalized tonic-clonic seizures alone

There are over 200 genes that have been identified as "epilepsy genes." Many other genes have also been shown to cause genetic disorders that can involve epilepsy or seizures.

These genes can be linked to epilepsy in several ways, including:

• Causing epilepsy directly (may be part of a genetic disorder that has epilepsy as a characteristic or symptom)
• Causing epilepsy as a result of an interaction between genetic and environmental factors
• Causing brain malformations that can lead to epilepsy
• Inherited conditions that increase the likelihood of seizures, such as inherited metabolic conditions

Affected genes can have:

• Mutations in the mitochondrial DNA
• Missing or mutated chromosomes
• Changes in the activity of genes

In some cases, a genetic cause may be suspected, but the exact cause of epilepsy can't be pinpointed.

Some gene mutations don't cause epilepsy to develop but can still affect a person with epilepsy. For example, some people with epilepsy have an abnormally active version of a certain gene, making them more resistant to anti-seizure drugs.

Inherited Epilepsy vs. Genetic Pathogenic Variants

If epilepsy results from a known or presumed genetic variant, it is considered to have a genetic cause. This does not necessarily mean the person inherited their epilepsy.

Changes in genes, called genetic pathogenic variants, can occur spontaneously, meaning a child can have these affected genes even if neither biological parent does.

Just having gene mutations that increase the risk of epilepsy doesn't necessarily mean you will develop epilepsy. In many cases, other factors, such as environmental conditions, are needed for the genetic predisposition to lead to the development of epilepsy.

Inheritance can play a role too. The risk of epilepsy is increased 2 to 4 times for first-degree relatives of a person with inherited epilepsy. Even with this increased risk, the overall risk of developing epilepsy is still low.

The risk is higher if the biological mother has epilepsy than if the biological father does. (Note that when research or health authorities are cited, the terms for sex or gender from the source are used.)

Having a sibling with epilepsy can also increase the risk, especially an identical twin.

Inherited epilepsy can be complex. For example:

• Siblings who have different gene mutations can develop the same epilepsy syndrome.
• Family members with the same gene mutation can have epilepsy but experience the effects differently.
• An epilepsy syndrome may be known to have a genetic basis, but the specific affected gene or genes haven't been identified.
  

Symptoms of Genetic Epilepsy

"Epilepsy" is an umbrella term for a group of disorders, each with its own characteristics. The symptoms of genetic epilepsy can vary.

Idiopathic generalized epilepsy involves both sides of the brain and can affect all areas of the body. It usually starts in childhood or adolescence.

Symptoms of generalized seizures include:

• Convulsions (uncontrollable shaking)
  
• Stiffening
• Making motions that are jerky, twitching, or rhythmic
• Crying out/making a noise
• Falling down
• Not breathing
• Losing consciousness
  
• Confusion after regaining consciousness
• Losing bladder control
• Biting the tongue

Some people with epilepsy experience partial seizures (also called focal seizures). Partial seizures start in a specific area of the brain and can affect just one part or side of the body.

Symptoms of partial seizures include:

• Movements that are jerky, rhythmic, and/or repetitive
• Sensations such as tingling
• Dizziness
• Feeling full in the stomach
• Staring
• Confusion
• Altered senses
• Emotional changes
  

If the epilepsy is caused by a genetic syndrome, additional symptoms may be present.

Treatment 

Genetic epilepsy is usually treated with anti-seizure medication.

If medication isn't effective or isn't a viable option, other treatments may be tried, such as:

• Surgery to remove the area of the brain that is causing the seizures
• Vagus nerve stimulation with a placed or implanted electrical device
• Special diets, such as a ketogenic diet or a specific supplement (always check with your healthcare provider before trying a special diet or supplement)

Therapies targeting specific rare genes may provide beneficial treatments in the future but are still in the research phase.

Other Causes of Epilepsy

Epilepsy can be caused by a number of factors in addition to genetics.

Head Trauma

Head trauma that causes brain injury, such as a car accident, can lead to epilepsy. Seizures may not show up immediately after the traumatic head injury, but appear later on.

Clinically significant elevated risk comes from moderate and severe traumatic brain injury (TBI), where there is at least 30 minutes of unconsciousness or more than 24 hours of disorientation, usually paired with hemorrhage or other traumatic findings on a brain scan.

Infections

Infections such as meningitis, human immunodeficiency virus (HIV), and viral encephalitis, can cause epilepsy. Infections experienced by a pregnant parent may contribute to the development of epilepsy in their baby.

Brain Abnormalities

Epilepsy can be caused by damage to the brain, such as from a stroke or brain tumors. The leading cause of epilepsy in people over the age of 35 is damage from a stroke.

Brain malformations, including vascular malformations, may also result in epilepsy.

Prenatal Injury

Brain injury in the womb leading to epilepsy can result from several factors, including:

• Oxygen deficiencies or deprivation
• Nutritional deficiencies
• Infection in the pregnant person

Developmental Disorders

Some developmental conditions, such as autism spectrum disorder or neurofibromatosis, can coexist with epilepsy.

Risk Factors for Epilepsy

While it's often not known why a person develops epilepsy, some factors may increase the risk, including:

• Significant head injury
• Brain tumor
• Brain infection
• Stroke
• Alzheimer's disease
• Lack of oxygen at birth
• Hardening of the arteries in the brain
• Age (more common in children and in older adults than in ages in between)
• A family history of epilepsy

Summary

Epilepsy can have a genetic component, which may or may not be inherited. Mutations in genes that can lead to epilepsy may be passed down from a biological parent or occur spontaneously.

Being genetically predisposed to epilepsy (having one or more affected genes) doesn't necessarily mean you will develop epilepsy. Often epilepsy develops through an interaction between genetic and environmental factors.

Epilepsy is usually treated with medication, but other treatments such as surgery, vagus nerve stimulation, or diet therapy, may be suggested.

If you have or suspect you or your child has epilepsy, talk to your healthcare provider. It's important to get a proper diagnosis and start any necessary treatment as early as possible.