Jett, living with Dravet syndrome
Jett, living with Dravet syndrome

Dravet Syndrome

Dravet syndrome, a rare developmental and epileptic encephalopathy, is a severe, lifelong disorder of the central nervous system (CNS).

Dravet syndrome equally affects patients of both sexes and all races, typically with frequent, prolonged and difficult-to-treat seizures that begin in the first year of life of a previously healthy baby. With seizures persisting with the type and frequency changing over time, other symptoms such as cognitive delays, sleep abnormalities, motor impairment and behavioral difficulties often appear in the second or third year of the child’s life.

This is a difficult journey for any family as Dravet syndrome can impact every aspect of their lives.


Despite the various signs, obtaining a confirmed diagnosis of Dravet syndrome can be difficult and take around one to four years. While a Dravet syndrome diagnosis is usually based on a combination of clinical features, genetic testing is important to determine the underlying cause of the disorder and provide appropriate and timely treatment and care.

The majority of individuals diagnosed with Dravet syndrome have an SCN1A mutation, specifically loss-of-function mutations in one copy of the SCN1A gene. Because these individuals only have one working copy of the SCN1A gene, the production of sodium channels commonly found on GABAergic neurons in the brain is impaired resulting in a loss of inhibitory activity. In turn, this leads to disruption of the brain’s excitatory-inhibitory balance resulting in seizures and other symptoms of Dravet syndrome.

Dravet syndrome with an SCN1A mutation


There are currently no approved therapies that address the full spectrum of symptoms associated with Dravet syndrome or the underlying cause of the disorder. Because Dravet syndrome has a genetic cause, it is an ideal candidate for gene therapy treatments.

Encoded is developing ETX101, a potential one-time, disease-modifying gene regulation therapy for SCN1A+ Dravet syndrome. The objective of ETX101 is to deliver genetic instructions, using an adeno-associated virus (AAV) vector, to GABAergic neurons in the brain. The aim is to up-regulate the activity of an individual’s working copy of the SCN1A gene. This is expected to increase the number of sodium channels to physiological levels and restore the brain’s excitatory-inhibitory balance.

The animation below provides a deeper look into ETX101 and its potential role for treating SCN1A+ Dravet syndrome.

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ENVISION Clinical Study

ENVISION was a natural history study for children aged 6 to 60 months living with SCN1A+ Dravet syndrome. This study was observational and aimed at understanding the natural course and impact of Dravet syndrome over time. No gene therapy or other investigational treatments were provided to participants of this study.

For more information about ENVISION (NCT04537832), visit and search for “Encoded Therapeutics”.

Dravet Engage

DRAVET ENGAGE, an ongoing initiative to capture the Dravet syndrome patient community’s experiences and perspectives and to solicit feedback on clinical study protocols and designs, as well as on educational materials.

As Encoded works towards creating a potentially one-time disease-modifying gene therapy for Dravet syndrome, we engaged with caregivers living in the USA, UK and Spain to learn about their experiences with the syndrome and understand their expectations, priorities, concerns and desired outcomes from clinical studies. The findings from these conversations and survey have been reported in a 2021 publication in Epilepsy & Behavior. Stay tuned for more updates about this initiative in the future!

Connect with the Dravet Syndrome Patient Community

The following is a representation of organizations that offer resources and information on Dravet syndrome.

Apoyo Dravet
DEE-P Connections
Dravet Syndrome European Federation
Dravet Syndrome Foundation
Dravet Syndrome UK
Genetic Epilepsy Team Australia
Sindrome de Dravet Fundacion

Links to sites outside of this website are provided as a resource to the viewer. The web pages and their content are independently maintained by the third-party organizations listed above. Encoded Therapeutics does not endorse any particular organization or the content contained on their websites.

If your group would like to be included in this list of organizations, please reach out to us at By providing your information, you agree to allow Encoded to collect the name and email address provided and to be contacted by Encoded and its partners using this information.

Additional Information

To learn more about Encoded’s Dravet syndrome clinical program or to connect with a member of our Patient Advocacy & Engagement team, please email If you are a healthcare provider looking for addition information, please contact Encoded’s Medical Affairs team at By providing your information, you agree to allow Encoded to collect the name and email address provided and to be contacted by Encoded and its partners using this information.

Page sources: Nabbout 2013; Brunklaus 2012; Gataullina and Dulac 2017; Wirrell EC, et al. 2017; Aledo-Serrano A & Mingorance A. 2020; Claes 2001; Wu 2015; Scheffer 2019; Wu 2015; Ogiwara 2007