Familial Epilepsy: Expert Explains The Genetic And Environmental Factors Behind Inherited Seizures

Epilepsy can be tough to deal with, and when it runs in families, it adds a deeper layer of concern. For many, familial epilepsy is a shared journey, with the condition affecting multiple generations, hinting at a genetic link. However, it’s not just about genetics. Environmental factors, like head injuries or infections, can also play a role in triggering epilepsy. If you have a family history of epilepsy, it’s natural to wonder about your own risk. We spoke to our expert Dr Shiva Kumar HR, Consultant - Neurologist, Gleneagles BGS Hospital Kengeri, Bengaluru, who explained the genetic and environmental connection of familial epilepsy.

"Familial epilepsy refers to cases where epilepsy runs in families, suggesting a genetic component to the condition. While family history can increase the likelihood of epilepsy, the overall risk is influenced by a combination of genetic and environmental factors. The risk of inheriting epilepsy varies depending on these factors and the specific type of epilepsy involved," explained Dr Kumar.

According to a 2021 study, children with parents who have epilepsy are 2–10 times more likely to develop the condition compared to those without a family history of epilepsy.

Genetic Factors Of Epilepsy

According to a 2019 study, epilepsy is a condition with significant genetic influences. Relatives of individuals with epilepsy are more likely to develop the disorder, even in families that don't follow Mendelian (single-gene) inheritance patterns.

Here are some genetic factors linked to familial epilepsy, as listed by the expert:

1. Family History: A strong family history is one of the most important risk factors for epilepsy. If a first-degree relative (parent or sibling) has epilepsy, an individual’s risk increases compared to the general population.
2. Genetic Mutations: Certain gene mutations, especially those affecting ion channels and neurotransmitter receptors, are linked to a higher risk of epilepsy. These mutations can disrupt normal brain signalling, leading to seizures.
3. Inheritance Patterns: The inheritance of epilepsy may follow different patterns. In some cases, it’s autosomal dominant, meaning one mutated gene from one parent is enough to increase risk. Other cases follow an autosomal recessive pattern, requiring two copies of a mutated gene (one from each parent). More complex inheritance patterns, involving multiple genes and environmental factors, are also possible.

Risk Estimates

1. General Population: The overall risk of developing epilepsy in the general population is about 1-2%.
2. First-Degree Relatives: The risk increases to 4-8% if a person has a first-degree relative with epilepsy.
3. Second-Degree Relatives: For individuals with a second-degree relative (grandparent, aunt, uncle, cousin) with epilepsy, the risk is lower, at around 2-4%.
4. Multiple Affected Family Members: When more than one close relative has epilepsy, the risk increases significantly.

Types of Epilepsy with Stronger Familial Links

Certain types of epilepsy are more likely to have a genetic basis. Dr Kumar listed them as follows:

1. Idiopathic Generalised Epilepsy: Conditions like juvenile myoclonic epilepsy tend to run in families.
2. Familial Temporal Lobe Epilepsy: This form of epilepsy, which affects the brain’s temporal lobe, has a stronger familial link.
3. Autosomal Dominant Nocturnal Frontal Lobe Epilepsy: This rare type of epilepsy, where seizures occur primarily at night, follows an autosomal dominant inheritance pattern.
4. Epilepsy Syndromes: Syndromes, such as Dravet syndrome and Lennox-Gastaut syndrome have genetic links and often occur in multiple family members.

Non-Genetic Factors

"While genetics play a key role in familial epilepsy, non-genetic factors are also important. These include prenatal exposure to harmful substances, birth complications, head trauma, infections, and metabolic disorders, all of which can increase the likelihood of developing epilepsy," added Dr Kumar.

Diagnosis of Familial Epilepsy

1. Family and Medical History: A thorough assessment of family history is critical to identifying any potential genetic links.
2. Diagnostic Imaging: Tests, such as EEG, CT scans, or MRI can help detect abnormal brain activity or structural issues.
3. Genetic Testing: In cases with a strong family history, genetic testing may be recommended to identify specific mutations and provide personalised risk estimates.

Bottomline

Dr Kumar concluded, “Familial epilepsy highlights the interplay of genetic and environmental factors. While having a family history increases the risk, many people with epilepsy do not have affected relatives, and not all families with a history of epilepsy will pass it on. Genetic testing and personalised assessments help in better understanding and managing this condition.”

[Disclaimer: This article contains information provided by an expert and is for informational purposes only. Hence, we advise you to consult your own professional if you are dealing with any health issues to avoid complications.]