Cause-Related Epilepsy

For about half people diagnosed with epilepsy, a specific cause of epilepsy may be found. Knowing the cause can give valuable information on what to expect over time. For example, some causes may be associated with

  • Types of seizures
  • Likelihood of seizures responding to therapy
  • Chance of outgrowing seizures
  • Types of treatments that may work best
  • Other problems or health conditions that may be seen

This section talks about types of epilepsy related to specific causes.

Genetic

Epilepsy is said to have a genetic cause if seizures are the result of a known or presumed genetic defect or problem associated with epilepsy. A genetic epilepsy might not be inherited. Some genetic pathogenic variants (or changes in genes) can occur spontaneously in a child without being present in either parent. Furthermore, some epilepsies with a genetic cause may also have additional environmental causes as well.

Explore the Following to Better Understand Genetics and It's Connection to Epilepsy

There are several types of genetic causes.

Inherited Gene Changes

Examples: autosomal dominant, autosomal recessive for X-linked disorders

In these conditions, the affected gene is inherited from one or both parents. Most genes have more than one copy. Boys who have pathogenic variants on the X chromosome are the exception – they have only one copy of the affected gene.

  • Some conditions (autosomal dominant disorders) require only one copy of the gene. In these cases, one or the other parent typically also has the condition.
  • Others (autosomal recessive disorders) require two copies of the abnormal gene for the epilepsy to occur. In autosomal recessive disorders, each parent usually carries one copy of the affected gene and one copy of the unaffected gene. They do not show any symptoms of epilepsy. The child will show evidence of the condition (in this case epilepsy) if they inherit both copies of the affected gene.

Acquired Gene Changes

These conditions arise from pathogenic variants that are “new” in the affected individual.

  • Many of these occur as a “de novo” event. This means the genetic changes happen when cells are dividing and forming in the body. These types of genetic conditions are not inherited from either parent.
  • Some individuals may be “mosaic” for a condition. This term means that genetic abnormalities are present in only some cells in an individual rather than all cells. Whether these genetic changes result in seizures depends on which cells and how many are affected.
  • “Germline pathogenic variants” are changes in genes in the gonadal cells of a parent (for example, the eggs or the sperm). They are not found in other cells. The parent is not affected but the risk of the gene change showing up in other children would be high.

Polygenic Affected Genes

These types of epilepsies are the result of changes in many genes. These genes can also be affected by environmental factors. When this happens, there is a higher chance of epilepsy in other family members, but no clear pattern of inheritance.

Specific Genetic Epilepsies

Find information about gene variants associated with epilepsy here.

Structural

Epilepsy is said to have a structural cause if there is a distinct, physical cause present in the brain that is known to substantially increase the risk of seizures.

Structural abnormalities can be

  • Congenital: a developmental change in the brain the person is born with. Some congenital structural causes may also have a genetic component.
  • Acquired: some process or injury has occurred, such as tumor, stroke, or trauma.

Specific Structural Epilepsies

Find information about structural causes associated with epilepsy here.

Metabolic

Epilepsy may have a metabolic cause if the way the body uses food to make energy is disrupted. It may also happen if the breakdown of a specific substance in food is impaired so it builds up in brain cells affecting normal function.

Most metabolic disorders are genetic.

Specific Metabolic Epilepsies

Find information about metabolic causes associated with epilepsy here.

Immune

Epilepsy is said to have an immune cause if there is brain inflammation from a protein that alters brain excitability leading to seizures. Most, but not all, people with an immune cause will have an abnormal antibody, either in the cerebrospinal fluid or blood.

Review the Following to Better Understand How Changes in the Immune System Can Cause Epilepsy

Specific Autoimmune Epilepsies

Find information about immune changes associated with epilepsy here.

Infection

Epilepsy is said to have an infectious cause if there is proof of a brain infection that leads to seizures. Infection is probably the most common cause of epilepsy worldwide but is more common in the developing world.

Specific Infections Associated with Epilepsy

Find information about infections associated with epilepsy here.

Authored By: 
Elaine Wirrell MD
Authored Date: 
09/2019
Reviewed By: 
Beth Rosen Sheidley MS, CGC
Elaine Wirrell MD
on: 
Sunday, April 26, 2020