National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Dravet syndrome

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Other Names:
Severe Myoclonic Epilepsy of Infancy; SMEI; Myoclonic epilepsy, severe, of infancy; Severe Myoclonic Epilepsy of Infancy; SMEI; Myoclonic epilepsy, severe, of infancy; SME See More
Categories:
Dravet syndrome is the most severe of a group of conditions known as SCN1A-related seizure disorders. Symptoms include seizures which first occur in infancy, and are often triggered by high temperatures (febrile seizures). In childhood, many types of seizures may occur and increase in frequency. Seizures may be difficult to treat. Other symptoms include loss of motor skills, intellectual disability, speech impairment, and difficulty with movement. Most cases of Dravet syndrome occur when the SCN1A gene is not working correctly. It can be inherited in an autosomal dominant pattern, but most people with Dravet syndrome do not have a family history of the condition. Diagnosis is based on a clinical exam, medical history, and the results of genetic testing. The main goal of treatment is to reduce the number and length of seizures.[1][2][3]
Last updated: 7/6/2020
The following list includes the most common signs and symptoms in people with Dravet syndrome. These features may be different from person to person. Some people may have more symptoms than others and symptoms can range from mild to severe. This list does not include every symptom or feature that has been described in this condition.

Signs and symptoms include: 
  • Febrile and other types of seizures
  • Sudden muscle jerking (myoclonus)
  • Loss of developmental skills
  • Intellectual disability
  • Problems with walking
  • Speech impairment
  • Autistic-like behavior
The first seizures appear before one year of age and are often associated with high temperatures. In childhood, other types of seizures develop and the frequency of seizures increases. Loss of developmental and cognitive skills may occur along with speech impairment and difficulty walking. In adulthood, the number of seizures may decrease, and nighttime seizures may occur. More serious complications include the risk of continuous seizures (status epilepticus) and sudden unexplained death.[1][2][4]
Last updated: 7/6/2020

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Developmental regression
Loss of developmental milestones
Mental deterioration in childhood
[ more ] 		0002376
Progressive gait ataxia 0007240
30%-79% of people have these symptoms
Anxiety
Excessive, persistent worry and fear
0000739
Atypical absence seizure 0007270
Autistic behavior 0000729
Bradykinesia
Slow movements
Slowness of movements
[ more ] 		0002067
Cognitive impairment
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment
[ more ] 		0100543
Cogwheel rigidity 0002396
Complex febrile seizure 0011172
Epilepsia partialis continua 0012847
Facial tics
Cramping of facial muscles
Facial spasms
Jerking of facial muscles
Mimic spasms
Spasms of facial muscles
Twitching of facial muscles
[ more ] 		0011468
Focal aware seizure 0002349
Focal hemiclonic seizure 0006813
Focal impaired awareness seizure 0002384
Generalized clonic seizure 0011169
Limited neck range of motion 0000466
Multifocal epileptiform discharges 0010841
Myoclonus 0001336
Obsessive-compulsive trait
Obsessive-compulsive traits
0008770
Parkinsonism 0001300
Photosensitive myoclonic seizure 0001327
Photosensitive tonic-clonic seizure 0007207
5%-29% of people have these symptoms
Action tremor 0002345
Cyanotic episode 0200048
Drooling
Dribbling
0002307
Dysgenesis of the hippocampus 0025101
EEG with generalized epileptiform discharges 0011198
Global brain atrophy
Generalized brain degeneration
0002283
Impulsivity
Impulsive
0100710
Incoordination
Difficulties in coordination
Incoordination of limb movements
Limb incoordination
[ more ] 		0002311
Infantile muscular hypotonia
Decreased muscle tone in infant
0008947
Limited knee extension 0003066
Pallor 0000980
Pes planus
Flat feet
Flat foot
[ more ] 		0001763
Pes valgus 0008081
Poor fine motor coordination 0007010
Short attention span
Poor attention span
Problem paying attention
[ more ] 		0000736
Status epilepticus without prominent motor symptoms 0031475
Tibial torsion 0100694
1%-4% of people have these symptoms
Generalized tonic seizure 0010818
Percent of people who have these symptoms is not available through HPO
Ataxia 0001251
Autosomal dominant inheritance 0000006
Cerebral atrophy
Degeneration of cerebrum
0002059
Cerebral visual impairment 0100704
Epileptic encephalopathy 0200134
Generalized myoclonic seizure 0002123
Generalized non-motor (absence) seizure
Brief seizures with staring spells
0002121
Global developmental delay 0001263
Infantile onset
Onset in first year of life
Onset in infancy
[ more ] 		0003593
Mental deterioration
Cognitive decline
Cognitive decline, progressive
Intellectual deterioration
Progressive cognitive decline
[ more ] 		0001268
Motor delay 0001270
Postnatal microcephaly 0005484
Status epilepticus
Repeated seizures without recovery between them
0002133
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Last updated: 7/1/2020
In some cases, Dravet syndrome is inherited in an autosomal dominant pattern.[4] All individuals inherit two copies of each gene. Autosomal means the gene is found on one of the numbered chromosomes found in both sexes. Dominant means that only one altered copy of a gene is necessary to have the condition. The alteration can be inherited from either parent. Dravet syndrome usually occurs due to a new genetic change that occurs for the first time in a person and is not present in either parent (de novo mutation).
  
Each child of an individual with an autosomal dominant condition has a 50% or 1 in 2 chance of inheriting the alteration and the condition. Typically, children who inherit a dominant alteration will have the condition, but they may be more or less severely affected than their parent. Sometimes a person may have a gene alteration for an autosomal dominant condition and show no signs or symptoms of the condition.
Last updated: 7/6/2020
Dravet syndrome is diagnosed based on the results of a clinical exam looking for specific symptoms that have been previously seen in this condition.[5] Genetic testing can also be helpful.[2]

Diagnosis is important because certain anti-seizure medications (sodium-channel agents) can make the seizures worse in Dravet syndrome.[2]
Last updated: 7/6/2020

Testing Resources

  • Orphanet lists international laboratories offering diagnostic testing for this condition.
Treatment for Dravet syndrome is focused on reducing the number and length of seizures. The seizures seen with Dravet syndrome are usually difficult to control, and people with this condition often need to take multiple anti-seizure medications. Certain types of anti-seizure medications (sodium-channel agents) can make the seizures worse, and should be avoided. New medications are being tested that are proven to be helpful in this condition.[2][3] 

Specialists who may be involved in the care of someone with Dravet syndrome include:
  • Neurologist
  • Developmental pediatrician
  • Physical therapist
  • Occupational therapist
  • Speech therapist
Last updated: 7/6/2020

Management Guidelines

  • Orphanet Emergency Guidelines is an article which is expert-authored and peer-reviewed that is intended to guide health care professionals in emergency situations involving this condition.  

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

  • Stiripentol (Brand name: Diacomit) - Manufactured by Biocodex
    FDA-approved indication: August 2018, stiripentol (Diacomit) was approved for the treatment of seizures associated with Dravet syndrome (DS) in patients 2 years of age and older taking clobazam.
    National Library of Medicine Drug Information Portal
  • Cannabidiol (Brand name: Epidiolex) - Manufactured by GW Pharma Ltd.
    FDA-approved indication: June 2018, cannabidiol (Epidiolex) was approved for the treatment of seizures associated with Lennox-Gastaut syndrome (LGS) or Dravet syndrome (DS) in patients 2 years of age and older. Sept 2018, the DEA (US Drug Enforcement Agency) placed Epidolex in schedule V of Controlled Substance Act. However, availability may be dependent on laws of individual States.
    National Library of Medicine Drug Information Portal
    Medline Plus Health Information
  • Fenfluramine HCI (Brand name: Fintepla) - Manufactured by Zogenix, Inc
    FDA-approved indication: Fintepla (fenfluramine) is indicated for the treatment of seizures associated with Dravet syndrome in patients 2 years of age and older.
    National Library of Medicine Drug Information Portal
It is estimated that 1 in 15,700 to 1 in 40,000 people has Dravet syndrome.[6] The exact number of people with this condition is unknown.
Last updated: 7/6/2020

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnoses include Lennox-Gastaut syndrome and myoclonic-astatic epilepsy (see these terms).
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Dravet syndrome. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.
  • Orphanet lists European clinical trials, research studies, and patient registries enrolling people with this condition. 

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Dravet syndrome. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Dravet syndrome:
    International Ion Channel Epilepsy Patient Registry
     

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Social Networking Websites

  • RareConnect has an online community for patients and families with this condition so they can connect with others and share their experiences living with a rare disease. The project is a joint collaboration between EURORDIS (European Rare Disease Organisation) and NORD (National Organization for Rare Disorders).

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Financial Resources

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Dravet syndrome. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Lagae L, Brambilla I, Mingorance A, Gibson E, Battersby A. Quality of life and comorbidities associated with Dravet syndrome severity: a multinational cohort survey. Dev Med Child Neurol. 2018; 60(1):63-72. https://pubmed.ncbi.nlm.nih.gov/28984349.
  2. Gataullina S, Dlac O. From genotype to phenotype in Dravet disease. Seizure. 2017; 44:58-64. https://pubmed.ncbi.nlm.nih.gov/27817982.
  3. Knupp KG, Wirrell EC. Treatment Strategies for Dravet Syndrome [published correction appears in CNS Drugs. 2018 Aug;32(8):783. Abstract corrected].. CNS Drugs. 2018; 32(4):335-350. https://pubmed.ncbi.nlm.nih.gov/29594870.
  4. Miller IO & Sotero de Menezes MA. SCN1A-Related Seizure Disorders. GeneReviews. May, 2014; http://www.ncbi.nlm.nih.gov/books/NBK1318/.
  5. Wirrell EC, Laux L, Donner E, et al.. Optimizing the Diagnosis and Management of Dravet Syndrome: Recommendations From a North American Consensus Panel.. Pediatr Neurol. 2017;68:18-34.e3.. 2017; 68:18-34.e.3. https://pubmed.ncbi.nlm.nih.gov/28284397.
  6. Wu YW, Sullivan J, McDaniel SS, et al. Incidence of Dravet Syndrome in a US Population. Pediatrics. 2015; 136(5):e1310-1315. https://pubmed.ncbi.nlm.nih.gov/26438699.
  7. Epileptic encephalopathy, early infantile, 6 (EIEE6). Online Mendelian Inheritance in Man (OMIM). Updated 7/9/2016; http://omim.org/entry/607208.
  8. Dravet syndrome. Orphanet. 2014; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=33069.