Clinical phenotypes of epilepsy associated with GABRA1 gene variants

Abstract

Objective: To summarize the clinical phenotypes of epilepsy in patients with GABRA1 gene variants. Methods: A total of 11 epileptic patients (4 boys and 7 girls) who were treated in the Department of Pediatrics, Peking University First Hospital from March 2016 to July 2019 and detected with GABRA1 gene heterozygous pathogenic variants by targeted next-generation sequencing were enrolled. The features of clinical manifestations, electroencephalogram (EEG), and neuroimaging were analyzed retrospectively. Results: A total of 11 epileptic patients carried GABRA1 gene pathogenic variants, of whom 10 were de novo variants and the other one was inherited from the patient's mother. Two patients had the same variants. Six variants were novel. Ages at seizure onset ranged from 3 to 14 months, and the median age was 8 months. The seizure was first observed within 1 year in 10 patients and beyond 1 year of age in 1 patient. Multiple seizure types were observed, including focal seizures in 10 patients, generalized tonic clonic seizures (GTCS) in 3 patients, myoclonic seizures in 3 patients, and epileptic spasm in 2 patients. There were 5 patients with multiple seizure types. Sensitivity to fever was observed in 9 patients, among whom 6 patients had a history of status epilepticus. Two patients had photoparoxysmal response. Five patients had abnormal EEG background, and 6 patients had abnormal discharges in EEG during interictal phase. Brain magnetic resonance imaging (MRI) was normal in all patients. Developmental delay in various degrees was present in 9 patients. Among the 11 patients, Dravet syndrome was diagnosed in 5 patients, West syndrome in 2 patients, undiagnosed early-onset epileptic encephalopathy in 1 patient, and focal epilepsy in the other 3 patients. The ages at the last follow-up ranged from 8 months to 12 years. During follow-up, 8 patients were seizure-free for 6 months to 8 years, and 1 patient had discontinuation of medication. Conclusions: In epilepsy associated with GABRA1 gene variants, de novo pathogenic variants are more common than inherited. Most epilepsy caused by GABRA1 gene variants occurs in infancy. Most patients have multiple seizures and focal seizures are common. Most patients have a comparatively favorable prognosis, but they may still have varied degrees of developmental delay.