Connection Between Down Syndrome and Epilepsy

Epilepsy, which has many causes, also has a close connection to Down syndrome (DS). The condition, in which a surge of electrical energy can cause brain seizures, is believed to affect anywhere from 1 to 13 % of children with DS.

While we don't yet fully understand the line, we tend to see it either in children under two years of age or in adults around their 30s. The types of seizures can vary from short "infantile spasms" lasting only a couple of seconds to more severe "tonic-clonic" seizures.

Child with Down syndrome

Understanding Down Syndrome

Down syndrome, also known as trisomy 21, is a genetic abnormality characterized by the presence of an additional chromosome 21. Normally, a person has 46 chromosomes (or 23 pairs). People with DS have 47.

Children with DS are faced with abnormalities, including characteristic facial features, heart and gastrointestinal problems, and an increased risk of leukemia. The majority of those over the age of 50 will also experience a decline in mental function consistent with Alzheimer’s disease.

In addition, people with DS have a higher risk of developing seizures in comparison to the general population. The could be due in part to abnormalities in the function of the brain or to conditions such as cardiac dysrhythmia, which can trigger a seizure.

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The Link Between Epilepsy and Down Syndrome

Epilepsy is a common feature of Down syndrome, occurring at either a very young age or around the third decade of life. The types of seizure also tend to vary by age. For example:

  • Younger children with DS are susceptible to infantile spasms (which may be short-lasting and benign) or tonic-clonic seizures (which result in unconsciousness and violent muscle contractions).
  • Adults with DS, by contrast, are more prone to either tonic-clonic seizures, simple partial seizures (affecting one part of the body with no loss of consciousness), or complex partial seizures (affecting more than one part of the body).

While almost 50 percent of older adults with DS (50 years and older) will have some form of epilepsy, seizures are typically less common.

Possible Explanations of Epilepsy in Down Syndrome

A great many cases of epilepsy in children with Down syndrome have no obvious explanation. However, we can reasonably infer that it has to do with abnormal brain function, primarily an imbalance between the "excitation" and "inhibitory" pathways of the brain (known as the E/I balance).

This imbalance may be the result of one or several factors:

  • A decreased inhibition of the electrical pathways (effectively releasing the "brakes" on the process meant to prevent overstimulation).
  • An increased excitation of brain cells.
  • Structural abnormalities of the brain that can lead to electrical overstimulation.
  • Change in the levels of neurotransmitters, such as dopamine and adrenaline, which can cause brain cells to abnormally fire or not fire.

Treating Epilepsy in People With Down Syndrome

Treatment of epilepsy typically involves the use of anticonvulsants designed to support the inhibitory pathways of the brain and prevent the misfiring of cells. Most cases are fully controlled with either one or a combination of anticonvulsants.

Some doctors support treatment with a ketogenic diet. The high-fat, low-carbohydrate dietary routine is believed to reduce the severity or frequency of seizures and is usually begun in a hospital with a one- to two-day fasting period.

A Word From Verywell

Having a child with Down syndrome doesn't mean that they will develop epilepsy. With that being said, you need to recognize the signs of epilepsy and contact your pediatrician immediately if you believe that your child has experienced a seizure. 

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Arya R, Kabra M, Gulati S. Epilepsy in children with Down syndrome. Epileptic Disord. 2011;13(1):1-7. doi:10.1684/epd.2011.0415

  2. Scorza CA, Scorza FA, Arida RM, Cavalheiro EA. Sudden unexpected death in people with down syndrome and epilepsy: another piece in this complicated puzzle. Clinics. 2011;66(5):719-720. doi:10.1590/S1807-59322011000500001

  3. NIH National Library of Medicine. Down syndrome.

  4. Shao L, Habela CW, Stafstrom CE. Pediatric epilepsy mechanisms: expanding the paradigm of excitation/inhibition imbalance. Children. 2019;6(2):23-. doi:10.3390/children6020023

  5. Epilepsy Foundation. Summary of antiepileptic drugs

By Reza Shouri, MD
Reza Shouri, MD, is an epilepsy physician and researcher published in the Journal of Neurology. Dr. Shouri has always been fascinated with the structure and function of the human brain.