SCN8A self‐limited infantile epilepsy: Does epilepsy resolve?

Abstract

AbstractSCN8A variants cause a spectrum of epilepsy phenotypes ranging from self‐limited infantile epilepsy (SeLIE) to developmental and epileptic encephalopathy. SeLIE is an infantile onset focal epilepsy, occurring in developmentally normal infants, which often resolves by 3 years. Our aim was to ascertain when epilepsy resolves in SCN8A‐SeLIE. We identified unpublished individuals with SCN8A‐SeLIE and performed detailed phenotyping. Literature was searched for published SCN8A‐SeLIE cases. Nine unpublished individuals from four families were identified (age at study = 3.5–66 years). Six had their last seizure after 3 years (range = 4–21 years); although drug‐responsive and despite multiple weaning attempts (1–5), five of six remain on antiseizure medications (carbamazepine, n = 3; lamotrigine, n = 2). We identified 29 published individuals with SCN8A‐SeLIE who had data on seizure progression. Of the 22 individuals aged at least 10 years, reported here or in the literature, nine of 22 (41%) had seizure offset prior to 3 years, five of 22 (23%) had seizure offset between 3 and 10 years, and eight of 22 (36%) had seizures after 10 years. Our data highlight that more than half of individuals with SCN8A‐SeLIE continue to have seizures into late childhood. In contrast to SeLIE due to other etiologies, many individuals have a more persistent, albeit drug‐responsive, form of epilepsy.