Dravet syndrome, previously known as severe myoclonic epilepsy of infancy (SMEI), is a type of epilepsy with seizures that are often triggered by fever. It appears during the first year of life, often beginning around six months of age with frequent febrile (fever-related) or prolonged non-febrile seizures. The seizures worsen with age and can be managed with anticonvulsant medications and ketogenic diet. However, some sodium channel blocker drugs such as carbamazepine are now known to worsen the seizures in Dravet patients.
In 70–90% of the patients, Dravet syndrome is caused by nonsense mutations in the SCN1A gene resulting in a premature stop codon resulting in a non-functional protein. Most of these mutations are not inherited and arise spontaneously. This gene normally codes for neuronal voltage-gated sodium channel Na(V)1.1. In mouse models, loss-of-function mutations in SCN1A gene reduce sodium currents and impair the excitability of hippocampal GABAergic interneurons. In addition, mutations in another voltage-gated sodium channel gene, SCN2A can also cause Dravet syndrome.
Dr. Gary Clark, Chief of Neurology at Texas Children’s Hospital participated in a large multi-center study to examine the effects of cannabidiol on drug-resistant seizures in Dravet syndrome patients. Cannabidiol (CBD) is a cannabis compound that is non-pyschoactive and has been found to have medicinal uses. This study found that cannabidiol reduced the frequency of convulsive-seizures compared to patients who were administered with the placebo. However, it was also associated with higher rates of adverse events and had no effect on non-convulsive seizures. Learn more
Texas Children’s Hospital is one of the 48 locations that are currently participating in an international, multicenter study to test the long-term safety of ZX008 (Fenfluramine Hydrochloride) as an adjunctive therapy in pediatric and young adults with Dravet syndrome. Learn more