Dravet syndrome (DS), previously known as severe myoclonic epilepsy in infancy (SMEI), is an epileptic encephalopathy that presents with prolonged seizures in the first year of life. The seizures often occur with fever or illness, and are frequently initially categorized as febrile seizures.

It is a rare form of early-onset genetic epilepsy syndrome that manifests as intractable epilepsy and neurodevelopmental delays. DS was included as a part of eight epileptic encephalopathy syndromes, as reported by the International League against Epilepsy (ILAE) task force. DS patients have an increased mortality rate during infancy but some survive till adulthood. Sudden unexpected death in epilepsy (SUDEP) and status epilepticus are the most common cause of death among DS patients.

Most cases of Dravet syndrome are caused by mutation in the SCN1A gene, which is required for the proper function of brain cells. Dravet syndrome is a lifelong condition.

Factors triggering seizures in DS are infection, environmental heat including hot baths, immunization, sunlight, pattern stimulation, exercise, or excitement.

Signs and Symptoms

Symptoms include seizures which first occur in infancy that are often triggered by high temperatures (febrile seizures). In childhood, many types of seizures may occur and they may increase in frequency. Other symptoms include

• loss of motor skills,
• intellectual disability,
• speech impairment, and
• difficulty with movement.