What is Dravet syndrome?
Dravet syndrome is an epilepsy condition that begins in infancy or early childhood. The condition belongs to a group of severe epilepsies—called developmental and epileptic encephalopathy (DEE)—that are characterized by often drug-resistant seizures and significant developmental delays.
Symptoms of Dravet syndrome
Dravet syndrome can include a range of mild to severe symptoms. Children with Dravet syndrome have different types of seizures that start in infancy, typically between 6–12 months. They can have different types of seizures, but most have tonic-clonic (also called grand mal) seizures. Tonic-clonic seizures affect the whole brain and start with a sudden loss of consciousness, followed by body stiffening (tonic phase) then jerking movements all over the body. Other children have hemi-clonic seizures that cause jerking on one half of the body.
Often, children will have fevers alongside the seizures. The seizures may generally change over time and are often difficult to treat. Status epilepticus—a state of continuous seizure requiring emergency medical care—may happen frequently, particularly before age five.
Additional symptoms may happen throughout childhood, such as:
Who is more likely to have Dravet syndrome?
Dravet syndrome is a genetic condition. Most people with Dravet syndrome have a de novo (or new) change in the SCN1A gene. This means the genetic change (variant) isn’t inherited but rather happened on its own.
The SCN1A gene is involved in making proteins called sodium ion channels. These channels transport sodium ions into brain cells and play a key role in a cell's ability to create and send electrical signals. A change in this gene can result in an imbalance of electrical activity that causes seizures and epilepsy.
In rare cases, the genetic variant in SCN1A that causes Dravet syndrome can be inherited from a parent. In this case, it’s possible that the parent carrying the variant is mildly affected, perhaps with seizures that happen with fever but not the cognitive problems usually associated with Dravet syndrome. The inheritance is autosomal dominant, which means a person only needs to inherit one copy of the affected gene from either parent to have the disease.
In some cases, Dravet syndrome presents as somatic mosaicism—where some of a person's cells have the gene variant while others don't. These people may have very mild symptoms of Dravet syndrome or no symptoms at all. If a parent’s gametes (egg or sperm cells) have the variant present, they’re still able to pass the variant on to their children. These children might be more severely affected than the parent from whom they inherited the variant.
While most people with Dravet syndrome have disease-causing variants in the SCN1A gene, there are a few other genes that can cause similar symptoms. For example, PCDH19-related epilepsy causes clusters of seizures or status epilepticus with fever in girls and shares many characteristics with Dravet syndrome.
If you think someone in your family may have Dravet syndrome or that you might be a carrier, let your medical team know and they may refer you for genetic testing.
How is Dravet syndrome diagnosed and treated?
Diagnosing Dravet syndrome
To diagnose Dravet syndrome, a doctor will perform a physical exam and review the person’s symptoms and medical history. The doctor may suggest tests such as an electroencephalogram (EEG) and an MRI (magnetic resonance imaging). But EEG and MRI test results are often normal when seizures first appear.
Find out more about neurological diagnostic tests and procedures.
If a doctor suspects Dravet syndrome, they may suggest a genetic test to look for a variant in the SCN1A gene. A variant in this gene can help support the diagnosis. If they don’t find any variants, the doctor may diagnose Dravet syndrome based on the person’s symptoms. Getting a diagnosis early can help children with Dravet syndrome get the care and support they need. A genetic counselor can provide information about genetic testing and what the test results could mean.
A genetic diagnosis of Dravet syndrome with a SCN1A variant may help the person be eligible for clinical trials.
Treating Dravet syndrome
Dravet syndrome is a lifelong condition. Treatments can help manage the person’s symptoms. The main goal of treatment is to reduce or stop seizures. Doing so will help prevent life-threatening conditions such as status epilepticus and SUDEP (sudden unexpected death in epilepsy).
Seizures in Dravet syndrome are often difficult to control. Medicines can help reduce the number and severity of some seizures. Anti-seizure medicines used to treat Dravet syndrome include valproic acid, clobazam, topiramate, and stiripentol.
The U.S. Food and Drug Administration (FDA) also has approved the drugs fenfluramine and cannabidiol to treat seizures in people with Dravet syndrome. Cannabidiol can be given starting at one year of age, and fenfluramine is approved in people two and older. Clinical trials of gene-based therapy are currently underway and may provide specific treatments for Dravet syndrome in the future.
Some seizure-controlling medicines (such as oxcarbazepine, carbamazepine, phenytoin, and lamotrigine) may make seizures worse in people with Dravet syndrome.
The ketogenic diet (high in fats and low in carbohydrates) is also used as an anti-seizure treatment and can be effective in people with Dravet syndrome. Physical, occupational, and speech therapy also may help with the overall symptoms and quality of life for individuals with Dravet syndrome. Families and healthcare providers should look out for changes in posture and gait that may develop in late childhood, including the development of a “crouch gait.” Physical therapy can help with gait and walking problems.
What are the latest updates on Dravet syndrome?
NINDS, a part of the National Institutes of Health (NIH), is the leading federal funder of research on the brain and nervous system, including research on seizure conditions like Dravet syndrome. NINDS conducts and supports new and innovative research to better understand, diagnose, and treat these disorders.
NINDS-funded researchers are using animal models to better understand genetic epilepsies like Dravet syndrome and to identify promising new treatment options for these conditions.
Other scientists supported by NINDS are seeking new insight on how genetic variants change the way brain cells process information and learn, and how these changes can lead to seizures, developmental delay or intellectual disability, autism, and other developmental issues.
In another NINDS-funded study, scientists are trying to identify additional genes that may contribute to the severity of Dravet syndrome. They believe identifying these genes will provide information about the underlying causes of epilepsy and lead to novel ways to improve treatment.
Learn more about NINDS research into epilepsy.
For more information on research about Dravet syndrome, check NIH RePORTER, a searchable database of current and past research projects funded by NIH and other federal agencies. RePORTER also has links to publications and resources from these projects.
For research articles and summaries on Dravet syndrome, search PubMed, which contains citations from medical journals and other sites.
How can I or my loved one help improve care for people with Dravet syndrome?
Clinical trials increase our understanding of Dravet syndrome with the goal of improving how doctors treat it. Consider participating in a clinical trial so clinicians and scientists can learn more about Dravet syndrome and related disorders. Clinical research with human participants helps researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.
All types of participants are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities. This helps make sure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone using them.
For information about participating in clinical research, visit the NINDS Clinical Trials site and NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with Dravet syndrome at ClinicalTrials.gov, a searchable database of current and past federal and private clinical studies and research results.
Where can I find more information about Dravet syndrome?
Information may be available from the following sources: