From genotype to phenotype in Dravet disease
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Updated: Mar 12, 2026
A Behavioral Screen for Heat-Induced Seizures in Mouse Models of Epilepsy
Published on: July 12, 2021
Svetlana Gataullina1, Olivier Dulac2
1INSERM U1129 "Infantile Epilepsies and Brain Plasticity", Paris, France; Paris Descartes University, PRES Sorbonne Paris Cité, Paris, France; CEA, Gif sur Yvette, France; AdPueriVitam, Antony, France; Neuropediatrics Department, Bicêtre Hospital, Paris-Sud University, Le Kremlin-Bicêtre, France.
Insights
Dravet syndrome, a severe epilepsy, involves early-life seizures and later non-epileptic issues like intellectual disability. SCN1A gene mutations cause NaV1.1 dysfunction, impacting brain function and leading to diverse symptoms.
Area of Science:
- Neuroscience
- Genetics
- Pediatric Neurology
Background:
- Dravet syndrome presents with severe epilepsy starting in infancy, often triggered by fever.
- It progresses to include various seizure types and significant non-epileptic developmental challenges.
- Sudden Unexpected Death in Epilepsy (SUDEP) has a high incidence across all age groups.
Purpose of the Study:
- To comprehensively review the clinical spectrum, pathophysiology, and management of Dravet syndrome.
- To highlight the genetic basis, SCN1A haploinsufficiency and NaV1.1 dysfunction, underlying the syndrome's diverse manifestations.
- To discuss current and potential therapeutic strategies.
Main Methods:
- Literature review of Dravet syndrome, focusing on clinical presentation, genetic etiology, and treatment outcomes.
- Analysis of the role of SCN1A mutations and NaV1.1 channel dysfunction in neuronal circuits.
- Synthesis of information on antiepileptic drugs, ketogenic diet, and emerging therapies.
Main Results:
- Dravet syndrome exhibits a wide range of seizures and progressive non-epileptic features including intellectual disability, ataxia, and gait disturbances.
- SCN1A haploinsufficiency leads to NaV1.1 dysfunction, primarily affecting GABAergic interneurons, explaining epilepsy and other neurological deficits.
- Certain antiepileptic drugs (sodium channel blockers) can exacerbate symptoms, while others (valproate, stiripentol) and ketogenic diet show efficacy.
Conclusions:
- Dravet syndrome is a complex neurodevelopmental disorder caused by SCN1A mutations, extending beyond epilepsy.
- Targeting the underlying NaV1.1 dysfunction is crucial for improving both epileptic and non-epileptic manifestations.
- A tailored therapeutic approach, avoiding specific drug classes and considering the ketogenic diet, is essential for management.
Abstract:
Dravet syndrome combines clonic generalized, focal or unilateral seizures, beginning within the first year of life, often triggered by hyperthermia whatever its cause, including pertussis vaccination. Long-lasting febrile seizures are frequent in infancy and repeat status epilepticus (SE) has negative prognostic value. Massive myoclonus, rare absences, complex partial seizures and generalized spikes may appear several years later. Myoclonic status may occur in childhood, but acute encephalopathy with febrile SE followed by ischemic lesions and psychomotor impairment, the most severe condition, occurs mainly within the first five years of life. Generalized tonic-clonic and tonic seizures in sleep predominate in adulthood. Non epileptic manifestations appear with age, including intellectual disability, ataxia and crouching gait. Incidence of SUDEP is high, whatever the age. SCN1A haploinsufficiency producing NaV1.1 dysfunction mainly affects GABAergic neurons. In cortical interneurons it explains epilepsy, in cerebellum the ataxia, in basal ganglia and motor neurons the crouching gait, in hypothalamus the thermodysregulation and sleep troubles, and dysfunction in all these structures contributes to psychomotor delay. Valproate, stiripentol, topiramate and bromide are the basis of antiepileptic treatment, whereas inhibitors of sodium channel worsen the condition. Benzodiazepines seem to facilitate acute encephalopathy when given chronically, and they should be restricted to SE. Ketogenic diet is useful in both chronic and acute conditions. Only targeting SCN1A haploinsufficiency and NaV1.1 dysfunction could improve non epileptic manifestations of this condition that deserves being considered as a disease, not only as an epilepsy syndrome.
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