One known cause of childhood epilepsy is mutations of the SCN1A gene on chromosome 2. The SCN1A gene contains instructions for the synthesis of proteins that regulate the function of sodium ion channels in neuron cells. The function of these sodium channels is to properly balance the amount of sodium ions inside and outside the cell, which is important for the maintenance of the healthy rhythm of electrical activity in the brain. When they do not function properly, imbalances occur, causing hyper-excitability of the neuron cells and lowering the seizure threshold.

Researchers have documented many different mutations of the SCN1A gene that result in febrile, sodium channel epilepsies, however most of them do not result in the severe form known as Dravet Syndrome or SMEI. There is a broad spectrum of severity, including benign Generalized Epilepsy with Febrile Seizures (GEFS), GEFS+, Severe Myoclonic Epilepsy, Borderline (SMEB) and Dravet Syndrome/SMEI.


GEFS -------------------- GEFS+ ----------------------- SMEB -------------------------DS/SMEI


Mutations of the SCN1A gene have an autosomal dominant inheritance pattern, meaning that they are passed from parent to child. However, mutations can occur “de novo”, meaning that the gene mutation and it is thought to have occurred spontaneously after conception.

At this time, the treatments available for the spectrum are to improve symptoms, primarily anticonvulsant medications to control seizures. The seizures are very resistant to therapy and the response to different medicines can be highly variable from child to child.