Severe myoclonic epilepsy in infancy, Polymorphic epilepsy in infancy, PMEI, Epilepsy with polymorphic seizures
Type of disease: Rare conditions
Dravet syndrome is a rare genetic form of epilepsy (seizure disorder) that begins during the first year of life. A mutation in gene SCN1A is responsible for Dravet syndrome. When this gene isn’t working properly, sodium channels in the brain (which help brain cells function) do not work correctly. Development is usually normal until age two but then further development becomes delayed. The severity of cognitive (intellectual) impairment is related to the frequency and duration of seizures. Children will not outgrow Dravet syndrome. About 1 in 300,000 babies born will have Dravet syndrome.
The first seizure is often associated with a fever. This type of epilepsy is characterized by unilateral (one-sided) clonic or tonic clonic (grand mal) seizures that may be prolonged (5 minutes) or progress to status epilepticus (30 minutes or more). Myoclonic seizures, often called myoclonic jerks, are common but not always present. Over time seizures present without fever, illness or heat triggers. Seizures are frequent and resistant to treatment. Future seizures may be triggered by slight changes in body temperature, flashing lights, emotional stress or excitement.
Diagnosis relies on seizure history as well as neurological exams and special tests like an EEG. About 80% of cases can be confirmed by genetic testing. Children diagnosed with Dravet syndrome will have multiple disabilities and associated complications. Treatment is aimed to find the best combination of medications that will prevent and treat seizure emergencies as well as addressing the other symptoms and delays. Physical, occupational, speech, and social/play therapies may be recommended for young children. Special diets may also be beneficial. Research is ongoing. If your child has been diagnosed with Dravet syndrome, talk to their pediatrician and specialists about the most current treatment options. Support groups may also be a good source of information and a community of support.