G327E mutation in SCN9A gene causes idiopathic focal epilepsy with Rolandic spikes: a case report of twin sisters.

The voltage-gated sodium channel NaV1.7, encoded by the gene SCN9A, is located in peripheral neurons and plays an important role in epileptogenesis. Previous studies have identified an increasing number of SCN9A mutations in patients with variable epilepsy phenotypes. Phenotypes of SCN9A mutations include febrile seizures (FS), genetic epilepsy with febrile seizures plus (GEFS+), and Dravet syndrome (DS), which pose challenges in clinical treatment. Here, we identified a heterozygous SCN9A mutation (c.980G > A chr2:167149868 p.G327E) from two twin sisters with Rolandic epilepsy by whole-exome sequencing. The patient became seizure free with a combination of levetiracetam and clonazepam. Identification of this mutation is also helpful for advancing our understanding of the role of SCN9A in epilepsy and provides deeper insights for SCN9A mutations associated with broad clinical spectrum of seizures.