Introduction: To summarize the electroclinical features of epilepsy associated with CHD2 mutations.

Methods: Patients with CHD2 mutations were collected. CHD2 mutations were identified by next-generation sequencing panels of epilepsy or whole exome sequencing.

Results: 17 patients with CHD2 mutations were enrolled. The onset age of seizure ranged from 3 months to 10 years and 5 months. Generalized tonic-clonic seizures (GTCS) were observed in 11 cases (11/17, 64.75%), and myoclonic seizures in 7 cases (7/17, 41.2%). Other seizure type included atonic seizure, atypical absence, focal seizure, myoclonic-atonic seizure and spasm. Status epilepticus was occurred in 2 patients. Moderate to severe intellectual disability were presented in 13 patients (13/17, 76.5%). Seven patients (7/17, 41.2%) had autistic spectrum disorders. Three patients exhibited microcephalus. Video electroencephalogram were abnormal in 15 patients. All of them had epileptiform discharges during interictal phase, and 8 cases were captured clinical seizures. Two cases has photosensitivity. Brain MRI was normal in all patients. Four cases were diagnosed with myoclonic-atonic epilepsy(MAE), two with febrile seizures plus (FS+), and one with nonspecific developmental epileptic encephalopathy. Seizures have been controlled in 8 (8/17, 47%) patients, 6 of whom have been controlled by valproate and/or levetiracetam. Seizures in 53% (9/17) patients were refractory and required multiple antiepileptic drugs. Three patients used ketogenic diet, two had cognition improvement.

Conclusion: The seizure onset age of patients with CHD2 mutations was in the early childhood. Seizures in most patients were refractory. The majority of patients had developmental delay.