This information is for people affected by or concerned about Dravet syndrome, including parents and carers.
On this page we talk about how Dravet syndrome is diagnosed, what causes it, symptoms, treatment options and long-term outlook.
Use this page as a general guide and speak to a health professional for more information and support.
On this page
What is Dravet syndrome?
Dravet syndrome is a very rare type of childhood epilepsy that usually starts in the first year of life. It affects around one in 15,000 children in the UK.
You may hear Dravet syndrome being called severe myoclonic epilepsy of infancy (SMEI). It is associated with different types of seizures, as well as learning and developmental problems.
What causes Dravet syndrome?
Dravet syndrome happens when one of the genes in a certain part of the brain does not function properly.
For 85 out of 100 children with Dravet syndrome, the cause is genetic. These children have a difference in a gene called SCN1A. Most of these children do not inherit this gene difference from a parent. It just happens during pregnancy.
For the remaining 10 to 15 out of 100 children with Dravet syndrome, the cause is unknown. Research is currently being carried out to fully understand the reasons why Dravet syndrome occurs in some people.
The seizures can often develop in the second year of life or later too. The seizures can be triggered by a few things, including:
- Changes in temperature (hot and cold)
- Teething
- Sensitivity to light and patterns
- Changes to medication
- Emotional stress or excitement
- Puberty and menstruation (periods).
What are the signs and symptoms of Dravet syndrome?
Dravet syndrome can often start with a sudden and irregular movement of the body (convulsion), which may happen as a response to a high temperature. For example, after a hot bath or fever.
A first seizure which is triggered by a high temperature is known as a febrile convulsion – they can last for more than five minutes and may occur in children younger than six months. However, febrile seizures are common in young children and, in most cases, do not lead to epilepsy. But always speak to a doctor if a child has had, or you think they have had a seizure. It’s important to understand what may have caused it.
Although most first seizures are triggered by a high temperature, everyone is different and Dravet syndrome can also be triggered by different things. Other triggers may include:
- physical activity
- excitement or emotional distress
- flashing or flickering lights (photosensitive epilepsy)
- teething
- changes to medication.
As children get older, other seizure types can develop. The seizures that develop after the first year of life can happen at any time, and can be triggered by different things including high temperatures and flashing lights.
How is Dravet syndrome diagnosed?
If you think a child has epilepsy, including Dravet syndrome, contact their doctor. They will ask for the child’s full medical history and may also carry out different tests to check if the child has Dravet syndrome.
You may be referred to a specialist doctor at a hospital, called a paediatrician. They are doctors who specialise in child health.
The doctor will ask for the child’s full medical history. They should have access to most of the information they need on the child’s medical record, but they may ask for additional information from the child’s parent or carer.
They may ask for information about:
- any seizures they have had in the past and the age at which they started
- the child’s development, for example, if you’ve noticed any delays in their learning
- a detailed family medical history.
Keep a record of seizuresIt may help to keep a note of any seizures, or symptoms of seizures, that the child has had. Any information you can give to the doctor about the child’s medical history is helpful and important. |
The doctor may need to carry out some tests on the child. This will help them to build a clear picture of the child’s health and work out if they’re likely to have Dravet syndrome.
Tests may include:
- An EEG (electroencephalogram) test – a painless test that uses small sensors attached to the scalp to pick up the electrical signals produced by the brain.
- An MRI (magnetic resonance imaging) scan – a scan that uses magnetic fields and radio waves to produce images from inside the body.
- A genetic test – a simple blood test, cheek swab or saliva sample can confirm whether or not a child has the different SCN1A gene that causes Dravet syndrome.
While tests are usually accurate at diagnosing Dravet syndrome, EEG and MRI test results are often normal, especially in the first year of life. Differences may only start to occur from around the age of two years. The child’s doctor will talk to you about their test results and what they mean.
What are the different types of seizures?
Children with Dravet syndrome may experience different types of seizures, these include:
- Febrile seizures
- Tonic-clonic seizures
- Clonic seizures
- Focal onset seizures
- Myoclonic seizures
We describe each seizure type in more detail below.
Febrile convulsions that can happen in the first year of life usually last between two to three minutes, but could last up to 10 minutes. Febrile seizures can affect one or both sides of the body.
Symptoms of a febrile seizure may include a loss of consciousness, uncontrollable shaking, eye rolling and rigid (stiff) limbs.
During a tonic-clonic seizure, the child may lose consciousness, go rigid (stiff) and fall. This is then usually followed by repetitive jerking of the limbs.
During a clonic seizure, the child may lose consciousness and fall. This is then usually followed by repetitive jerking of the limbs. Unlike with tonic-clonic seizures, their body will not go stiff.
Focal onset seizures occur in one area of the brain. The brain is divided into four parts known as lobes:
- frontal lobes
- occipital lobes
- parietal lobes
- temporal lobes.
What happens during the seizure will depend on which section of the brain is affected. Symptoms can range from subtle sensory changes to more severe movements in the body and loss of consciousness.
Children who have myoclonic seizures usually experience sudden muscle jerks. These types of seizures usually stop once the child is about five years old.
Seizures after the first year
After the first year of a child’s life, the type of seizures they experience may vary and they may become more frequent.
Treatments for Dravet syndrome
There is no cure for Dravet syndrome, but with the right medicine it can usually be managed, and seizures can be controlled.
Remember that everyone is different and what works for one person might not work well for someone else. People with Dravet syndrome may have to try a few different medicines until something works well.
Talk to your doctor about treatment options and what might be suitable. They should explain the benefits and risks of each treatment, including any possible side effects.
First treatment options
For people diagnosed with Dravet syndrome, the first recommended treatment is usually sodium valproate (also known as Epilim).
Sodium valproate comes as capsules, tablets or a liquid that you swallow. It also comes as granules that you mix with food or drink. It can also be given by injection, but this is usually only done in hospital or in emergencies.
Sodium valproate is the most effective treatment for managing seizures in people with Dravet syndrome.
But sodium valproate may not be suitable for everyone. This is because sodium valproate may affect fertility (the ability to get pregnant naturally).
For women who can have children, and young girls who are likely to need treatment when they’re old enough to have children, a doctor should consider the following things before prescribing sodium valproate:
- The benefits and potential risks of sodium valproate should be fully discussed, including any risks to an unborn child.
- The likelihood of pregnancy should be taken into account and if appropriate, a pregnancy prevention programme should be put in place, if appropriate.
Read more about the process for prescribing sodium valproate and the risks.
Sodium valproate
In January 2024, new rules were introduced for prescribing sodium valproate.
Two specialists are now needed to approve:
- New or ongoing valproate treatments for girls and women.
- New valproate treatments for boys and men
The specialists must agree that your epilepsy does not respond to other treatments and the benefits of treatment outweigh the risks.
For girls and women, valproate can seriously harm an unborn baby when taken during pregnancy.
For boys and men, valproate may cause infertility. Some people’s fertility may return when their treatment is stopped or reduced. There is also some evidence that valproate can cause harm in the testicles of animals, but it’s unclear what this means for humans.
Never stop taking valproate before talking to your specialist first. Not taking medication as prescribed can increase the risk of a seizure.
Your epilepsy specialist will let you know when your treatment is due to be reviewed.
If you are planning a pregnancy it is important to speak to your healthcare professional as soon as possible about your treatment options.
If you have any questions or concerns about valproate, please speak to your healthcare professional.
Find out more about sodium valproate in the MHRA’s patient guide.
Find out more about Anti-seizure medications, contraception and pregnancy.
If sodium valproate on its own does not work, then other anti-seizure medications can be tried together with sodium valproate. These are sometimes called ‘add-on’ treatments. They include:
Stiripentol (also known as Diacomit) – a medicine that comes as capsules or oral powder sachets, that you swallow.
- Clobazam (also known as Frisium and Onfi) – a medicine that comes as tablets or liquid, that you swallow.
When these medicines are being used as add-on treatments alongside sodium valproate, the child’s doctor will carefully review the doses of each and check often for any side effects, including sedation (sleepiness).
Second treatment options
If the combination of sodium valproate, stiripentol and clobazam does not work in a child who is over two years old, then a second add-on treatment option may be offered. The doctor may suggest trying a combination of:
- Cannabidiol (also known as Epidyolex) – a medicine that comes as a liquid, that you swallow.
- Clobazam (also known as Frisium and Onfi) – a medicine that comes as tablets or liquid, that you swallow.
Talk to a doctor if you’re not sure which medicines you, or a child with Dravet syndrome, should be taking. They will help to answer any questions that you have, including about the dose and how often each medicine should be taken.
Other treatment options
If the combination of sodium valproate, stiripentol, and clobazam does not work in a child under two years old, or the second add-on treatment option does not work in a child over two years old, a doctor may suggest trying one of the following add-on treatment options:
- Ketogenic diet – a special type of diet that is high in fat and protein, but low in carbohydrates. It can work well at reducing the intensity and frequency of seizures.
- Levetiracetam (also known as Keppra) – a medicine that comes as a tablet, liquid or granules, that you swallow.
- Topiramate (also known as Topamax) – a medicine that comes as a tablet or capsule, that you swallow.
If one of these options does not work, another add-on option can be tried. Remember, it can take time to find a medicine or combination of medicines that works well.
What’s the long-term outlook for people with Dravet syndrome?
Managing seizures can be difficult at any age. But for babies and small children it can be especially challenging. However, as children get older, usually by the time they are teenagers and young adults, seizures may happen less often. And with the right treatment and support, seizures can usually be managed.
Most children and young people with Dravet syndrome will have learning difficulties and delays to their development, particularly affecting their speech and language. These types of developmental delays are likely to continue throughout their life, even if seizures reduce.
As Dravet syndrome progresses, people with the condition may develop a particular way of walking. This includes becoming unsteady on their feet. This is called ataxia.
It’s likely that people with Dravet syndrome will need care and support from other people throughout their lives.
Living with Dravet syndrome and getting support
Dravet syndrome is a severe, life-long and complex form of epilepsy. It can be difficult and upsetting for parents or carers to manage a child’s learning difficulties as well as trying to control seizures.
Talk to the child’s doctor for help on how to support them well. And talk to your own doctor if you need support for yourself. If you’re caring for someone with Dravet syndrome, it’s important that you look after yourself and get the support you need.
You may find it helpful joining an in-person or online support group, where you can listen to or share experiences with other people who understand what you’re going through.
Other useful organisations
Dravet Syndrome UK
An organisation that supports people affected by Dravet Syndrome.
