The Link Between Down Syndrome and Epilepsy

Seizures often seen in children or adults in their thirties

Down Syndrome and Epilepsy
Getty Images

While there are many causes of epilepsy, It has a close connection to people with Down syndrome (DS). The condition, in which a surge of electrical energy can cause brain seizures, is believed to affect anywhere from five to 10 percent 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 in or 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.

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.

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 involuntary myoclonic jerks). 
  • 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 an estimated 45 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/L balance).

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

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

    It's important to remember that having a child with Down syndrome doesn't mean that he or she will develop epilepsy. With that being said, it is important to recognize the signs of epilepsy and to contact your pediatrician immediately if you believe that your child has experienced a seizure. 

    Sources:

    Arya, R.; Kabra. M.; and Gulati. S. "Epilepsy in children with Down syndrome." Epileptic Disorders. 2011; 13(1):1-7.

    Menendez, M. "Down syndrome, Alzheimer’s disease, and seizures." Brain & Development. 2005: 27:246-252.

    Continue Reading