What to know about Dravet syndrome

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The cause of Dravet syndrome is a gene mutation. Dravet syndrome most often results from a de novo variation, a genetic mutation not present in a child’s parents. It typically develops for the first time in the egg, sperm, or early embryo.

In 70–80% of individuals with Dravet syndrome, the mutation is in the SCN1A gene, which provides instructions for creating sodium channels found primarily in the brain. These channels control the flow of sodium ions and affect communication between nerve cells or neurons.

Researchers suggest that SCN1A gene mutations may result in uncontrolled firing from gamma-aminobutyric acid-ergic neurons. Gamma-aminobutyric acid (GABA) functions as the primary inhibitory neurotransmitter for the central nervous system.

Dravet syndrome appears to affect males twice as often as it affects females.

Symptoms of Dravet syndrome vary by person and often change as the individual gets older.

The three symptoms most commonly associated with this condition are seizures, developmental delays, and behavioral abnormalities.

Seizures

Most individuals with Dravet syndrome start to have seizures at the age of 5–8 months. The first seizure usually results from a trigger like a fever, but sometimes there is no trigger.

When a fever triggers a seizure, this is called a febrile seizure. Many infants have febrile seizures, and this symptom alone doesn’t mean a baby has Dravet syndrome.

Individuals with Dravet syndrome typically also develop other types of seizures, including:

• focal seizures, which occur in one area of the brain
• myoclonic seizures, which cause the upper body or legs to jerk or twitch
• atypical absence seizures, which cause lapses of consciousness that can last for 20 seconds or longer
• tonic-clonic seizures, which make the whole body twitch and jerk and cause a person to become unconscious

Individuals with Dravet syndrome can get a seizure when they experience stress, excitement, see flashing lights, or have a rapid change in body temperature.

Developmental delay

Parents typically begin to notice cognitive delays or difficulty learning and talking in infants with Dravet syndrome at 1–2 years old. It can take these infants longer to reach certain milestones compared with other children.

Hypotonia, a lack of muscle tone, is common in individuals with Dravet syndrome at around 1 year old. Parents may also notice signs of ataxia, a disorder that affects coordination and balance, when infants start walking.

Behavioral disturbances

The most common behavioral traits associated with Dravet syndrome relate to autism, attention deficit hyperactivity disorder, irritability, and aggression.

Dravet syndrome is rare and can be challenging for doctors to diagnose. According to the International League Against Epilepsy, a doctor generally uses the following characteristics to make a diagnosis:

• a family history of seizures or febrile seizures
• “normal” development before the onset of seizures
• a seizure during the first year of life, followed by an increasing number of various seizure types
• an EEG test with generalized spike and polyspike waves
• focal abnormalities or early photosensitivity
• psychomotor delays after the age of 24 months
• ataxia

Doctors typically recommend genetic testing in individuals likely to have Dravet syndrome.

At the time of publishing, there is no cure for this condition. However, treatments may decrease the number and severity of seizures. Treatment options include:

Medication

Doctors usually prescribe anticonvulsants to people with Dravet syndrome. These decrease the severity and amount of seizures. Two of the most common medications for Dravet syndrome are valproic acid and clobazam.

In 2018, the Food and Drug Administration (FDA) approved a new drug called Epidolex, which contains cannabidiol, to treat seizures associated with Dravet syndrome. In 2020, fenfluramine (Fintepla), previously an obesity treatment, was also approved for use in treatment-resistant children with the condition.

Diet

Research suggests the ketogenic diet, which is high in fat and low in carbohydrates, may help individuals with Dravet syndrome. The diet affects biochemical pathways involved in the functioning of the central nervous system. It also affects GABA levels.

Avoiding triggers

Avoiding seizure triggers is important for people with Dravet syndrome. Hot baths, jacuzzies, and flashing lights can all bring on seizures.

Learn more about the triggers of focal seizures here.

A vagus nerve stimulator

People with Dravet syndrome may benefit from a vagus nerve stimulator.

A doctor will perform surgery to insert a small electrical device in the person’s chest for this treatment. The device, which sends electrical impulses to the brain via the vagus nerve, may help reduce seizure frequency. The vagus nerve is involved in the function of the nervous system.

Treatment for developmental delays

There are many treatments for developmental delays, but none are curative. The most common treatments are occupational and physical therapy.

It is common for individuals with Dravet syndrome to have caretakers when they reach adulthood.

The average life expectancy of people with Dravet syndrome is not clear, but estimates suggest that 10–20% of individuals with Dravet syndrome do not survive beyond the age of 10.

Sudden unexpected death in epilepsy (SUDEP) is the most common cause. For this reason, neurologists recommend that parents of infants with this condition adopt SUDEP risk reduction strategies, such as seizure detection and baby monitoring devices.

The frequency of seizures in individuals with Dravet syndrome becomes less frequent as they reach adulthood, but they typically still have developmental and motor disabilities. Many adults with Dravet syndrome have caretakers to help with day-to-day activities.

As scientists come to understand this condition better, they continue to create improvements to current treatments. For example, Epidolex, the first FDA-approved drug for Dravet syndrome, may reduce seizure frequency by up to 39%.

Dravet’s syndrome is a rare form of epilepsy that begins in infancy. Genetic mutations cause the condition, which leads to seizures and developmental disabilities. The seizures can be challenging to control.

Doctors and researchers still do not truly know the average life expectancy of people with Dravet syndrome. Adults with the condition typically require the assistance of a caretaker to help with day-to-day activities.

There is no cure for Dravet’s syndrome, but symptoms can improve once an individual receives treatment. Doctors usually prescribe anticonvulsant medications and advise people with Dravet syndrome to avoid seizure triggers.