Is epilepsy genetic? Hereditary Factors and More Explained

Certain types of epileptic seizures and epileptic syndromes result from genetic factors. These include genetic differences that arise after inheriting certain genes from biological parents or changes made to genes after birth. Epileptic seizures occur when the usual pattern of electrical activity in the brain goes out of control. Epilepsy syndromes are a combination of certain types of epileptic seizures and a specific set of additional features.

Causes of epilepsy can include conditions such as trauma or acquired brain injury. However, genetic factors can also cause seizures and epileptic syndromes.

This article explains how genetics can cause the development of certain types of epilepsy. This article also describes other potential causes of epilepsy, as well as screening and treatment options.

Is epilepsy a genetic disease?

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In some cases, a genetic disease leads to the development of epilepsy.

Some epileptic syndromes are thought to be the result of a genetic condition. These epilepsy syndromes include:

  • childhood absence epilepsy (CAE)
  • juvenile myoclonic epilepsy (JME)
  • genetic epilepsy with febrile seizures plus (GEFS+)

DNA and other diagnostic tests can help doctors diagnose the cause of epilepsy.

How do genetics cause epilepsy?

Although more research is needed, researchers understand some ways genetics can cause or contribute to the development of epilepsy.

Genetic factors include inherited genetic changes, acquired genetic changes, and polygenic affected genes.

It is possible to inherit specific genes or genetic differences from your biological parents. These genes may increase the risk of developing epilepsy.

Not everyone with inherited genetic changes will develop epilepsy. For example, a child can live without having seizures even though both biological parents have epilepsy.

However, the risk of a child suffering from epilepsy increases if both biological parents have genetic changes linked to epilepsy.

Some genetic changes or mutations are not hereditary but develop from non-hereditary changes in a person’s DNA.

New, or “de novo,” changes can occur after conception, when cells divide and produce an error in the typical DNA structure.

Acquired genetic changes can also occur if the biological parents’ reproductive cells contain genetic differences. Clinicians call these differences “germline” mutations. Germline mutations do not affect the biological parents but can affect the embryo conceived from their reproductive cells.

Additionally, acquired genetic changes can include instances where some people experience “mosaic” cells for a condition. This means that some of their cells contain genetic differences, but others do not.

Polygenic Affected Genes

Epilepsy due to affected polygenic genes means that genetic changes have occurred in many genes. Environmental factors can also affect these genes.

Despite the lack of a clear link between heredity and polygenic affected genes, there is an increased risk that epilepsy will be present in other members of your family.

Other genetic diseases can lead to epilepsy.

For example, metabolic conditions can affect the functioning of brain cells. According to the Epilepsy Foundation, most metabolic disorders are genetic.

Additionally, congenital conditions that cause structural differences in the brain can increase the risk of seizures.

Congenital conditions are developmental changes or differences present at birth. Genetic inheritance causes certain congenital diseases and can therefore indirectly cause epilepsy.

Genetic conditions that cause epilepsy as a symptom include:

  • tuberous sclerosis
  • fragile X syndrome
  • Rett syndrome
  • neurofibromatosis 1 (NF1)

Types of genetic epilepsy

Epilepsy syndromes that have a genetic cause include:

  • Childhood absence epilepsy: CAE is an epileptic condition characterized by recurrent absence seizures. It usually begins when a child is between 3 and 8 years old. Both genetic and environmental factors can cause CAE.
  • Genetic epilepsy with febrile seizures plus: GEFS+ refers to various members of the same biological family who experience different types of seizures or epileptic syndromes. This may include multiple generations of family members.
  • Juvenile myoclonic epilepsy: JME is an inherited epileptic syndrome that typically presents with generalized absence, myoclonic, and tonic-clonic seizures. It is one of the most common childhood epilepsy syndromes. A family history of the disease is present in about 50% of cases.

According to the Epilepsy Foundation, other genetic types of epilepsy include:

  • Angelman Syndrome
  • CDKL5
  • PCDH19
  • ring chromosome 20
  • Related to SCN8A

Various conditions that affect the brain can cause epilepsy. Examples include:

  • brain tumour
  • brain injury such as a concussion
  • stroke
  • genetic disorders such as Down syndrome
  • neurological diseases such as Alzheimer’s disease
  • brain infections

Learn more about the causes of seizures and epilepsy.

Genetic test for epilepsy

If you have seizures or epilepsy, your doctor may suggest genetic testing to determine the cause. Knowing the cause can ensure that you receive the right treatment for your type of epilepsy. Also, a better understanding of your condition will help you know what to expect in the long run.

Genetic testing may include taking a DNA sample from your blood or saliva. Lab technicians will look for changes in your genes that may have caused your condition.

Genetic testing for epilepsy may include:

  • epilepsy gene panel
  • chromosome chip
  • whole exome sequencing
  • targeted testing

Your doctor may also suggest brain scans or EEGs, which monitor electrical activity in the brain.

It may be helpful to contact a genetic counselor or epilepsy specialist to discuss your test results. These specialists can also discuss the potential impacts on your biological family and the possibility of future children inheriting epilepsy.

If your epilepsy is genetic, you will likely need treatment for the rest of your life.

Learn more about treatment options for epilepsy.

Nancy Hammond, MD, has reviewed the following frequently asked questions.

What percentage of epilepsy is genetic?

According to Genetics Education Canada Knowledge Organization, genetic factors contribute to the onset of epilepsy in up to 70% of people with epilepsy. About 30% of people with epilepsy have the condition due to a mutation in a single gene that clinicians can detect through genetic testing.

Some epileptic seizures can occur due to genetic factors that cause epilepsy. These factors can include inheriting genetic differences or acquiring changes to your genes after conception.

Genetic factors can also cause seizures if you have another genetic condition that produces seizures as a symptom.

Epilepsy and epilepsy syndromes can be genetic. Inheriting genetic differences from biological parents or changes in genes after conception can cause epilepsy.

Other non-genetic causes of epilepsy include brain damage, stroke, and brain infections.

Clinicians can perform DNA tests to find out if genetic changes are the cause of epilepsy.

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