[Clinical features of epilepsies associated with GABRB2 variants]

Objective: To analyze the clinical phenotypes of epilepsies in children with GABRB2 variants. Methods: Data of 8 epileptic patients with heterozygous GABRB2 variants were retrospectively collected at the Department of Pediatrics, Peking University First Hospital from April 2016 to December 2018. The clinical, electroencephalographic, neuroimaging characteristics, therapeutic and follow-up were analyzed. Results: Eight patients (4 boys, 4 girls) with heterozygous GABRB2 gene pathogenic variants were enrolled. Eight patients had different GABRB2 variants, among whom 2 patients inherited the variants from either parent, and the other 6 patients had de novo variants. Seven variants were novel. Ages at seizure onset ranged from 1 day to 22 months after birth, and the median age was 6 months. The seizure was first observed within one month of age in 2 patients, 1-6 months in 2 patients, 7-12 months in 2 patients, and beyond 1 year of age in 2 patients. Multiple seizure types were observed, including focal seizures in 6 patients, generalized tonic clonic seizures (GTCS) in 4 patients, myoclonic seizures in 3 patients, and epileptic spasm in 2 patients. Developmental delay was present in 6 patients. In 8 patients, Dravet syndrome was diagnosed in 3 patients, febrile seizures plus and West syndrome in 2 patients, respectively, Ohtahara syndrome in 1 patient. Six patients had epilepsy with fever sensitivity, and status epilepticus developed in all these patients. The ages at the last follow-up ranged from 8 months to 11 years, and the follow-up data showed that 5 patients were seizure-free, and 2 patients still had seizures, and 1 patient died of recurrent status epilepticus complicated with fungal infection. Conclusions: Epilepsies associated with GABRB2 variants were characterized by an onset in infancy, and the clinical features were heterogenous in seizure types and severities. Most patients had multiple seizures with fever sensitivity, and status epilepticus was common. Their seizures were easily induced by fever or infection. Additionally, the majority of the patients had varying degrees of developmental delay.