Sleep-related hypermotor epilepsy with genetic diagnosis: description of a case series in a tertiary referral hospital

INTRODUCTION: Sleep-related hypermotor epilepsy (SHE) is characterized by asymmetric tonic/dystonic posturing and/or complex hyperkinetic seizures occurring mostly during sleep. Experts agree that SHE should be considered a unique syndrome. PURPOSE: We present 8 cases of SHE for which a genetic diagnosis was carried out using a multigene epilepsy panel. METHODS: We retrospectively screened familial and isolated cases of SHE in current follow-ups in our center. RESULTS: We included 8 (5F/3M) patients, 5 of whom had a positive familial history of epilepsy. We identified a pathogenic mutation in CHRNA4, CHRNB2, and 3 different pathogenic changes in DEPDC5. CONCLUSIONS: Awareness of SHE needs to be raised, given its implications for finding an appropriate treatment, its relationship to cognitive and psychiatric comorbidities, and the opportunity to prevent the disorder in the descendants. We present our series with their clinical, radiological, electroencephalographic, and genetic characteristics, in which we found 3 pathogenic mutations in the DEPDC5 gene but not previously reported in the literature. Identifying new pathogenic mutations or new genes responsible for SHE will facilitate a better understanding of the disease and a correct genetic counseling.