Dravet Syndrome

Also known as

  • Severe Myoclonic Epilepsy in Infancy (SMEI)

Dravet Syndrome is a catastrophic rare form of childhood epilepsy, with seizures that typically begin during the first year of life. Often the first seizures occur with fever and are generalised tonic-clonic (involving the whole body) or one-sided convulsions. These seizures are often prolonged and require emergency intervention. Seizures increase in frequency and begin to occur without fever. Additional seizure types also appear. The child’s development starts to slow down.

Condition details

Dravet Syndrome is a catastrophic neurological condition causing severe seizures alongside other conditions such as learning disability, ataxia and autism. The course of Dravet syndrome s variable from one child to another. Prolonged seizures continue to be a risk and may still be more likely to occur with fever and illness Currently, treatment for Dravet syndrome consists mainly of antiepileptic medications to help control seizures. Response is variable, but often the seizures persist despite treatment. Certain medications – currently including sodium valproate, clobazam, stiripentol, topiramate, levetiracetam – have been found to be generally useful.

I would like to edit or add detail to this database entry

Photos of affected individuals

Click images to enlarge.

Typical age range of first manifestation

  • Can manifest in Baby
  • Does not manifest in Toddler
  • Does not manifest in Child 4-10
  • Does not manifest in Child 10-18
  • Does not manifest in Adult


Lay terms Clinical terms
  • Rare form of epilepsy. Full body or one sided convulsions. Seizures lasting for more than 5 minutes. Single jerk seizures. Staring and unresponsiveness.
  • Neurodevelopmental disorder characterised by intractable seizures. Tonic-clonic seizures (formerly known as grand mal seizures). Prolonged seizures. Myoclonic
  • focal or atypical absence seizures.
Lay terms Clinical terms
  • Developmental delays become apparent. Unsteadiness walking/standing up. Poor sleeping. Behaviour problems. Seizures often occur in the child's sleep. Prolonged seizures are still a risk and may be brought on by external factors such as getting too hot.
  • Varying degrees of developmental delay typically become apparent. Ataxia. Sleep disturbance. Behaviour problems. As children grow older
  • focal and myoclonic seizures may lessen
  • and in some cases disappear
  • but convulsive seizures typically persist
  • often occurring from sleep. Communication
  • motor and cognitive functions stabilise
  • but significant delays persist. Higher risk of sudden unexplained death in epilepsy (SUDEP).

Affected genes identified to date

  • SCN1A gene is found in 80% of patients.

Inheritance patterns

Are carriers affected?

In Dravet syndrome, the gene mutation nearly always arises ‘de novo’, or new to the individual, even though many of the affected individuals have some history of febrile seizures or epilepsy in their extended family.

How many are affected?

1 in 40,000 but as the syndrome becomes better known the rate of diagnosis is increasing.

Support groups and organisations

Dravet Syndrome UK
Tel 08443 321 008

Known experts

No experts found

I would like to edit or add detail to this database entry

Please let us know more about you

In order to allow you to edit this form, please fill in the fields below and click submit to proceed to to the editing page.

used only if we have questions about your entry.

Share this page

Welcome to the GDUK network

If this is the first time you have searched for information on a particular condition, details you find here may be distressing.

» If you would rather read our Newly Diagnosed section for parents and carers first click here