Dravet Syndrome (previously called Severe Myoclonic Epilepsy of Infancy or SMEI), is an epilepsy that usually starts in the first year of life with frequent febrile convulsions that are often prolonged. In the second year of life generalised seizures appear. These are commonly myoclonic jerks and absence seizures, but generalised tonic-clonic and focal seizures can also occur. Status Epilepticus is also seen (prolonged seizures or clusters of frequent seizures requiring medication to stop the seizures).
What causes Dravet Syndrome?
The majority of children with Dravet Syndrome have a defect in the SCN1A gene (80%). However, in 20% of cases, testing may not reveal an abnormality in this gene and is likely due to a different gene. Most children with this identified gene abnormality have not inherited this from a parent, although this is a possibility and discussion with a genetic counsellor regarding family testing may be warranted.
Children with Dravet Syndrome are at risk of developmental and intellectual delays. This may not be initially apparent until the second year of life or later and appears to be linked to the frequency of seizures and prolonged seizures. Children with Dravet Syndrome can also have behavioural difficulties. The syndrome and medications can be associated with problems with attention, concentration, and problems processing and understanding information. Having a good understanding of the child’s developmental and intellectual abilities is therefore essential in understanding and managing behaviour.
Other common issues associated with Dravet Syndrome include:
- movement and balance issues
- orthopaedic conditions
- delayed language and speech issues
- growth and nutrition issues
- sleeping difficulties
- chronic infections
- sensory integration disorders
- disruptions of the autonomic nervous system (which regulates things such as body temperature and heart rate)