is epilepsy a genetic disease

Can Epilepsy be genetic?

Yes.

We get our genes from our Parents. They determine a lot of our features: our height, our skin colour, our eye colour, hair colour and so on. Genes also contain the information required to make the brain, the lungs, the liver and other organs of our body.

Therefore, if we have abnormal genes while growing up, we may develop abnormalities of the brain. We are now discovering that in many patients, the cause of Epilepsy is abnormal genes.

Just for the sake of completion, allow me to mention that there are two other causes of Epilepsy:

  • Injury to the brain after birth
  • Auto-immunity (when our own immune system reacts against our brain)

You can read more about these causes in this article (“What is the cause of Epilepsy?” – Click here).

How do abnormal genes produce Epilepsy?

Abnormal Genes can produce Epilepsy by one of 3 mechanisms. The table below has one example of each mechanism:

How does it cause Epilepsy?ExampleWhich Epilepsy syndrome does it produce?
By producing abnormal Brain Cells: Abnormal Sodium channels in brain cellsSCN1ADravet syndrome
By disrupting brain structure s e.g. by producing too many wrinkles on the surface of the brainADGRG-1Polymicrogyria
By causing chemical (Metabolic) problems: Problems in transporting glucose to the brainSLC2A1GLUT-1 deficiency syndrome

Genes causing Epilepsy – By producing abnormal brain cells

Our brain cells contain may pores. These pores are called “Channels”.

There are separate channels for specific chemicals. Thus, there are special channels for sodium, another set of special channels for potassium, and so on.

If there is a problem with one of these channels, the disease is called a “Channelopathy”. The Sodium channels are most commonly affected.

Abnormal sodium channels can cause sodium to flood into the brain cell. This causes a small surge of electricity. If this electricity becomes uncontrolled, you can have a seizure.

If you want to read about the exact genes, click the plus sign below. This is a list of important genes causing Channelopathy:

Genes causing Channelopathy
Substance affectedGeneEpilepsy Syndrome
SodiumSCN1ADravet Syndrome
SodiumSCN2ABenign Familial Infantile Seizures
PotassiumKCN-Q2 & 3Benign Familial Neonatal Convulsions
PotassiumKCNT1Malignant Migratory Partial Seizures of Infancy
CalciumCACNA1AChildhood Absence Epilepsy
Chloride/Calcium channelsGABRA1, EFHC1, CACNB3, CLCN2 & othersJuvenile Myoclonic Epilepsy
AcetylcholineCHRNA2, CHRNA4, CHRNB2Autosomal Dominant Frontal Lobe Epilepsy

For a even more detailed description of epilepsy genes producing abnormal channels, please click here [Bartolini et al 2020].

Genes causing Epilepsy – By disorganizing brain structure

The brain is a masterpiece of organization. Each cell is usually it’s God-given perfect place.

Sometimes, the cells are okay but their organization is disrupted.

This may cause problems such as:

  1. Too many wrinkles on the brain (polymicrogyria)
  2. Too few wrinkles on the brain (lissencephaly)
  3. Thickening of parts of the brain surface (Focal Cortical Dysplasia)
  4. Scarring of the brain part behind the ears (Mesial Temporal Sclerosis)
  5. etc…

Out of these problems, number 3 (Focal Cortical Dysplasia) is very important.

If you want, you can click on the + sign below. You can see all the known genes which can cause such problems:

Genes causing structural problems
GeneAbnormal Brain structure
DCX, Tuba1A, LisiLissencephaly
ADGRG-1 & Tubb2BPolymicrogyria
mTOR genes (DEPDC5, PTEN, NPRL2&3)Focal Cortical Dysplasia
Filamin-1Nodular Heterotopia
TSC1 & TSC2Tuberous Sclerosis
SCN1A, SCN1B, CNTNAP2Mesial Temporal Sclerosis
GNAQSturge-Weber
CCM1/KRIT-1, CCM2, CCM3Cavernoma

Genes causing Epilepsy – By causing Chemical problems

Our brain, like the rest of our body, is a finely tuned chemical factory.

It burns glucose for energy. This “burn” is a “slow burn”. Energy is gradually extracted, step-by-step. The waste products are sent to the liver/kidneys to be de-toxified or thrown out.

If this process is faulty, Brain cells do not get enough energy, or are exposed to toxic substances. This can cause seizures/Epilepsy.

This faulty process is called an “Inborn Error of Metabolism”. There is a huge number of genes that produce errors of Metabolism. The list is so large that it is not possible to describe each one here!

But that does not mean many people are affected by these genes. In fact, only a few patients with epilepsy have Inborn Errors of Metabolism (IEMs). Doctors typically test for these problems only if there are suspicious features such as consanguinity, repeated episodes of low blood sugar etc…

Here is a list of the important genes from a research paper. You can click here for the full version of the paper (Sharma et al 2017).

MetabolicCausesOfEpilepsy

Should I get genetic testing for Epilepsy?

Almost always, the answer is No.

Certainly not by yourself.

The question of which patients should get genetic testing is hotly debated, even amongst doctors. We just don’t know the answer yet.

If there is a strong family history of Epilepsy, many doctors will advise genetic testing. Here is how genetic testing may affect you:

  • It may identify your Epilepsy Syndrome conclusively.
  • Rarely, it may help in selecting the right medications.
  • Some researchers believe that genes may affect the outcome of surgery.
  • It may help to estimate the chances of your Child getting Epilepsy.

Genetic testing is gradually becoming more widely available. Now, certain doctors have started recommending testing at critical junctures, even if there is no family history. For example:

  • When medications are not working.
  • Before undergoing Epilepsy surgery.

It is important to remember that genetic testing is expensive, we cannot test for all mutations which cause Epilepsy, and at this point, it may not be possible to tailor your treatment based on your genes. However, it is also reasonable to expect that all these problems will have solutions in the future.

 

Footnote:

Footnote: In some cases, the genes from both parents are perfectly normal. But while the baby is growing in the womb, his/her normal genes may become abnormal. These are called “Somatic mutations”. This is a developing concept in Epilepsy, and therefore not discussed in detail here.

 

Caution: This information is not a substitute for professional care. Do not change your medications/treatment without your doctor's permission.
Dr. Siddharth Kharkar

Dr. Siddharth Kharkar

Dr. Siddharth Kharkar has been recognized as one of the best neurologists in Mumbai by Outlook India magazine and India today Magazine. He is a board certified (American Board of Psychiatry & Neurology certified) Neurologist.

Dr. Siddharth Kharkar is a Epilepsy specialist in Mumbai & Parkinson's specialist in Mumbai, Maharashtra, India.

He has trained in the best institutions in India, US and UK including KEM hospital in Mumbai, Johns Hopkins University in Baltimore, University of California at San Francisco (UCSF), USA & Kings College in London.

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