What causes Dravet syndrome?

What causes Dravet syndrome?

Dravet syndrome happens when there’s a change (mutation) in the SCN1A gene. Nearly 80% of children diagnosed with Dravet syndrome have the SCN1A gene mutation. However, having the mutation isn’t enough to make the diagnosis, and the absence of the mutation doesn’t exclude the diagnosis. There’s a range or family of related SCN1A gene mutation disorders. Not all children with this gene mutation will develop Dravet syndrome. The mildest condition along the range of SCN1A gene mutations is familial hemiplegic migraine. The most severe condition is Dravet syndrome.