Dravet syndrome is a rare, lifelong genetic condition that affects brain development and causes epilepsy. It usually begins during the first year of life with prolonged seizures, often triggered by fever, in a baby who was previously developing normally.
Over time, different seizure types may develop, and some children may also have developmental slowing, learning difficulties, behavioral changes, sleep problems, or problems with movement and balance. Seizures are often difficult to control and can have a major effect on daily life.
Treatment focuses on reducing how often seizures happen, how long they last, and how severe they are. Care usually involves an epilepsy specialist, antiseizure medicines, rescue medication, an individualized seizure action plan, and supportive therapies when needed.
Main symptoms
Dravet syndrome usually begins with seizures during infancy, but other symptoms can appear as a child grows.
The most common symptoms can include:
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Prolonged seizures, often triggered by fever
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Different types of seizures, including tonic-clonic, focal, myoclonic, or absence seizures
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Developmental slowing or regression
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Learning or intellectual difficulties
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Language or behavioral difficulties
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Problems with balance, walking, or movement
Not every person with Dravet syndrome has the same symptoms, and the severity can vary considerably.
What causes it?
Dravet syndrome is caused by a genetic change that affects how brain cells work. In more than 85% of cases, it is linked to a change in the SCN1A gene, which is important for normal electrical signaling in the brain.
In most people, this genetic change happens spontaneously and is not inherited from either parent. This is known as a de novo genetic variant.
Less commonly, the genetic change can be inherited from a parent. In these cases, the parent may have milder symptoms or a history of seizures linked to fever.
Not every change in the SCN1A gene causes Dravet syndrome. Doctors consider both genetic test results and the person's symptoms when making a diagnosis.
Confirming a diagnosis
Dravet syndrome should be considered when seizures begin during the first year of life in a baby who was previously developing normally. Features that raise suspicion include prolonged seizures associated with fever, seizures affecting one side of the body, convulsive status epilepticus, seizures that are difficult to control, and later developmental slowing or regression.
International expert guidance recommends considering genetic testing in previously typically developing infants between 2 and 15 months of age who have a prolonged hemiclonic seizure or convulsive status epilepticus with fever or after vaccination when no other cause has been identified. Genetic testing commonly includes testing for changes in the SCN1A gene.
An EEG or brain MRI may be normal during the early stages of Dravet syndrome, so normal early results do not rule it out. Diagnosis is based on the overall pattern of symptoms together with genetic findings when available.
Treatment options
There is currently no established cure for Dravet syndrome. Treatment focuses on reducing seizure frequency, duration and severity, while also supporting development and quality of life.
1. Antiseizure medicines
Dravet syndrome is often difficult to control with medication, and many people need more than one antiseizure medicine. Valproate and clobazam are commonly used, while stiripentol, pharmaceutical-grade cannabidiol and fenfluramine are also important treatment options.
In the United States, pharmaceutical-grade cannabidiol and fenfluramine are FDA-approved for seizures associated with Dravet syndrome. Treatment should be selected and monitored by an epilepsy specialist because medicines can have side effects and may interact with one another.
Some sodium-channel-blocking antiseizure medicines, including carbamazepine, oxcarbazepine, phenytoin and lamotrigine, may worsen seizures in Dravet syndrome. Decisions about medication should therefore be made by the treating specialist.
2. Rescue treatment and seizure action plan
Every person with Dravet syndrome should have access to home rescue medication and an individualized seizure action plan. This plan explains how to manage prolonged or repeated seizures and when emergency treatment is needed.
Emergency action is generally needed for a seizure lasting 5 minutes or longer, repeated seizures without recovery, breathing problems, a significant injury, or other situations identified in the person's seizure action plan. Specific instructions should come from the treating neurology team.
3. Ketogenic dietary therapy
A ketogenic diet may be considered when seizures remain difficult to control with medication. This type of dietary treatment should be planned and monitored by healthcare professionals.
4. Rehabilitation and supportive care
Dravet syndrome can affect development, movement, communication and daily activities in addition to causing seizures. Physical therapy, occupational therapy and speech therapy may be recommended to support these needs.
Care may also include support for behavioral difficulties, sleep problems, walking or balance problems, feeding concerns, and other developmental needs.
Possible complications
Dravet syndrome can have significant effects beyond seizures. Developmental disability, behavioral difficulties, problems with movement and balance, sleep disorders, and other medical concerns can contribute to a major long-term impact on both the affected person and their family.
Prolonged seizures and status epilepticus are important complications. Dravet syndrome is also associated with a risk of sudden unexpected death in epilepsy, known as SUDEP, which is one reason careful seizure management, emergency planning and ongoing specialist follow-up are important.