Clinical analysis of CHD2 gene mutations in pediatric patients with epilepsy

Importance:CHD2 is a member of the chromodomain helicase DNA-binding(CHD)family of proteins,which have important roles in the regulation of gene expression.Dysregulation of this protein may lead to various disorders.Objective:To delineate the genotypes and phenotypes of CHD2-related epilepsy.Methods:We analyzed the medical history,magnetic resonance imaging findings,and video-electroencephalogram recordings of 17 patients withCHD2 mutations in the Neurology Department of Beijing Children’s Hospital from June 2016 to June 2021.Results:Age at seizure onset ranged from 6 months to 10 years;the median age at onset was 4 years.Generalized tonic-clonic,myoclonic,eyelid myoclonic,atonic,atypical absence,myoclonic-atonic,and spasm seizures were observed.Ten of the 17 patients had multiple types of seizures.One patient exhibited photosensitivity epilepsy and one patient exhibited grid image-induced visual reflex epilepsy.Developmental disability was present in 14 patients,while autism features were present in five patients.Sixteen patients hadde novo mutations ofCHD2;one patient had an inherited variant.Eleven mutations were novel.One patient had two mutations;that patient exhibited development delay and refractory epilepsy.Seizures were controlled in eight patients,improved in seven patients,and resistant to treatment in two patients.Interpretation:Phenotype severity in patients withCHD2 variants ranged from drug-responsive seizures to severe epileptic encephalopathy.Most patients exhibited developmental disorders.