Infantile epileptic encephalopathy with a hyperkinetic movement disorder and hand stereotypies associated with a novel SCN1A mutation.

We report a female patient who presented with intractable epileptic seizures, profound developmental delay since early infancy, and hyperkinetic movements with hand stereotypies. The patient initially developed focal seizures with multiple foci at 3 months of age. Thereafter, the seizures evolved to frequent episodes of hyperthermia-induced status epilepticus. A novel de novo SCN1A mutation was identified by whole-exome sequence analysis. This case demonstrates that SCN1A mutations may cause movement disorders as an atypical phenotype and the case history of this patient may expand our understanding of the clinical spectrum of SCN1A-associated epileptic encephalopathy. [Published with video sequences].