Dravet Syndrome

What is Dravet syndrome?

Dravet syndrome is a rare and potentially severe form of epilepsy that starts in the first year of your baby’s life. A high fever usually triggers the first seizure your child experiences, which could last more than five minutes.

Children with Dravet syndrome have a wide range of seizure types. They also have many other symptoms, including developmental setbacks, speech and language problems, and balance and walking issues.

Dravet syndrome was previously known as:

• Severe myoclonic epilepsy of infancy
• Epilepsy with polymorphic seizures
• Polymorphic epilepsy in infancy

Long-lasting seizures may increase your child’s risk of an unexpected life-threatening outcome. Your child’s provider will help you plan for emergency seizure episodes, offer tips to keep your child safe and create a treatment plan to address your child’s needs.

What are the symptoms of Dravet syndrome?

A seizure is the first symptom of Dravet syndrome. It typically happens before your child’s first birthday. Their first seizure may:

• Last longer than five minutes
• Happen with a fever, illness or high environmental temperatures
• Cause uncontrollable muscle movements (convulsions)
• Affect only one or both sides of their body

After age 1, your child may have more seizures. These seizures may not be caused by rising temperatures. Different seizure types may include:

• Absence seizures. Short loss of consciousness with a blank stare
• Atonic seizures. Loss of muscle control and tone
• Hemiclonic seizures. Convulsions on only one side of their body
• Focal seizures. Loss of awareness and muscle control with abnormal sensations
• Myoclonic seizures. Quick muscle jerks
• Tonic-clonic seizures. Uncontrolled convulsions

Other symptoms of Dravet syndrome may include:

• Developmental delays (including difficulty with language development)
• Behavioral issues (aggression)
• Neurodevelopmental disorders (like ADHD)
• Balance and coordination difficulties
• Movement challenges like tremors or an abnormal gait (unsteady walk)
• Low muscle tone (hypotonia)
• Sleep disorders
• Growth and nutrition problems
• Dysautonomia (like difficulty regulating body temperature, heart rate or blood pressure)

What causes Dravet syndrome?

A genetic variant of the SCN1A gene causes most cases of Dravet syndrome. The SCN1A gene provides instructions to make sodium channels. These channels send sodium ions (positively charged sodium atoms) to your cells. They help your cells create and send electrical signals in your brain.

A genetic variant affects the structure of the channel, which interferes with how often your channels send electrical signals to your brain cells.

Is Dravet syndrome genetic?

Yes, Dravet syndrome is genetic. Most cases happen randomly and aren’t inherited (passed in your biological family history). But there are cases in which several members of the family in different generations could be affected. The abnormalities in the sodium channel affect the process of neurotransmission or communication between neurons in the brain.

In the few documented cases of inherited Dravet syndrome, a biological parent may have a genetic variant in some of their cells but not all of them (mosaicism). It may also pass in an autosomal dominant pattern, where only one biological parent needs to carry the genetic variant for the child to inherit it.

Having a genetic variant of the SCN1A gene doesn’t necessarily mean you’ll experience symptoms of Dravet syndrome. There are some cases where you may have the variant but not have symptoms of the condition or you’ll have symptoms of the condition but not have this genetic variant.

Not all people with an SCN1A variant will develop Dravet syndrome. You may have a form of epilepsy known as “genetic epilepsy with febrile seizures plus.” You might have focal epilepsy or familial hemiplegic migraines.

What are the risk factors for Dravet syndrome?

You may be more at risk of developing this condition if a biological parent or relative has a form of epilepsy or a genetic variant of the SCN1A gene.

What are the complications of Dravet syndrome?

The most serious complications may be life-threatening and could include:

• Injury from seizures
• Status epilepticus (continuous seizures that require immediate medical treatment)
• Sudden unexplained death in epilepsy (SUDEP)

Your child’s provider will let you know what signs to look out for and offer an emergency treatment plan to prevent life-threatening complications.

How is Dravet syndrome diagnosed?

Your child’s healthcare provider will perform a physical exam to look for the symptoms of Dravet syndrome. They’ll ask about your child’s medical and medication history, too.

Your child’s provider may also ask you the following questions:

• Did your child have normal (or near normal) development before the first seizure started?
• Did your child have two or more seizures, with or without fever, before 1 year of age?
• Did two or more seizures last longer than five minutes?
• Can you describe what happened during the seizure (did your child shake, stare or only move one side of their body)?

Their provider may offer blood tests or saliva tests to check for the SCN1A gene variant, along with imaging tests. A diagnosis is sometimes delayed, as magnetic resonance imaging (MRI) and electroencephalogram (EEG) results are usually normal at first.

How is Dravet syndrome treated?

The goal of treatment is to reduce the number and severity of your child’s seizures. Because seizures range in type and length, no two children respond to treatment in the same way. Treatment is individualized for each person and may include:

• Antiseizure medications. Antiseizure medications may reduce the number of seizures your child experiences. Your child’s provider will use caution and follow-up because some medications can make seizures worse.
• Ketogenic diet. Your child’s provider may recommend making changes to the foods they eat, which should be high in fats and low in carbohydrates.
• Therapies. Your child may benefit from educational intervention programs (for delayed development) in addition to physical, occupational or speech therapy to address any issues that may arise.

What medications treat Dravet syndrome?

The U.S. Food and Drug Administration (FDA) has approved the following medications to treat seizures associated with Dravet syndrome in people over age 2, including:

• Cannabidiol
• Fenfluramine
• Stiripentol

These medications are available in different forms (like a pill and liquid solution) to make it easier for both children and adults to take.

Your provider will recommend that you avoid antiseizure medications in the category of sodium channel blockers, like carbamazepine, oxcarbazepine, lamotrigine and phenytoin, as they may make seizures worse.

Your provider may recommend taking more than one type of medication to manage different types of seizures. The International Consensus on Diagnosis and Management of Dravet Syndrome recommends people try these drugs in this order:

• First line of treatment: Valproate
• Second line of treatment: Fenfluramine, stiripentol or clobazam
• Third line of treatment: Cannabidiol
• Fourth line of treatment: Topiramate, ketogenic diet

Rescue medications

Rescue medications are emergency treatments for continuous seizures (status epilepticus). Your child’s provider will help you develop a seizure action plan for home or school. Rescue medications may stop your child’s seizure. These are usually benzodiazepines, which include:

• Clonazepam
• Diazepam
• Lorazepam
• Midazolam

These medications can be found in various forms, including nasal sprays, rectal gels, or wafers or buccal films.

What’s the prognosis for Dravet syndrome?

Your child’s provider can give you information about their prognosis (outlook), which varies from person to person. Your child will have long-lasting and frequent seizures, but these tend to decrease in number and length as your child ages. Medications may reduce the number and severity of seizures, but it isn’t possible to be completely seizure-free with Dravet syndrome.

You can expect your child to need more time than their peers to meet developmental milestones for their age. They may need extra support in school, too. But their learning pace may improve as they get older.

Your child’s care team may recommend they see different specialists to address any concerns as they grow. For example, a podiatrist may help your child with walking challenges by fitting them with special orthotics, or an orthopaedic surgeon may help with gait issues or scoliosis.

Is there a cure for Dravet syndrome?

There isn’t a cure for Dravet syndrome right now. There’s also no way to prevent the condition because it’s genetic. But research is ongoing. There are good initial results from clinical trials using gene therapies.

What’s the life expectancy for a child with Dravet syndrome?

People diagnosed with Dravet syndrome have an increased risk of early death from sudden unexpected death in epilepsy, status epilepticus or accidental injury during seizures. However, many people diagnosed with this condition reach adulthood.

Your child’s provider can give you the most accurate information on what you can expect because your child’s situation may or may not match statistics.

When should I see a healthcare provider?

If your child has two or more prolonged seizures (seizures that last more than five minutes), especially if heat triggered the seizure (like a fever) before their first birthday, let their provider know. This is a sign of Dravet syndrome.

You’ll meet regularly with your child’s care team after they receive a Dravet syndrome diagnosis. Let their provider know if you notice your child has worsening seizures (more frequent or longer lasting) after starting treatment.

Their provider will tell you what signs and symptoms to look out for in case of an emergency. They’ll also give you instructions on what to do. Symptoms that require emergency treatment include:

• A seizure that lasts more than five minutes and causes difficulty breathing
• Multiple seizures that happen back-to-back and your child doesn’t wake up between each one
• A seizure that causes a physical injury