CHD2‐related epilepsy: novel mutations and new phenotypes.

The aim of this report was to refine the genotypes and phenotypes of chromodomain helicase DNA‐binding protein 2 (CHD2)‐related epilepsy. Seventeen patients with CHD2 mutations were enrolled. CHD2 mutations were identified by application of next‐generation sequencing of epilepsy or whole exome sequencing. Sixteen mutations were identified, among which 15 have not yet been reported. Thirteen mutations were de novo. Age at seizure onset ranged from 3 months to 10 years 5 months. Seizures observed were generalized tonic–clonic, myoclonic, atonic, atypical absence, focal, and myoclonic–atonic. Epileptic spasms occurred in two patients. Developmental disability was present in 14 patients. Autism features were observed in seven patients. Video electroencephalogram was abnormal in 15 patients. Five patients were diagnosed with non‐specific epileptic encephalopathy, two with epilepsy with myoclonic–atonic seizures, two with Lennox–Gastaut syndrome, two with febrile seizures plus, and one with West syndrome. Seizures were controlled in nine patients. Q1392TfsX17 may be a hot‐spot mutation of CHD2. West syndrome was observed as a new phenotype of CHD2 mutation. The severity of the phenotypes of CHD2 mutations ranged from mild febrile seizures to severe epileptic encephalopathy. What this paper adds: Q1392TfsX17 maybe the hot‐spot mutation of CHD2.West syndrome could be a new phenotype of CHD2 mutation. What this paper adds: Q1392TfsX17 maybe the hot‐spot mutation of CHD2.West syndrome could be a new phenotype of CHD2 mutation. This article's abstract has been translated into Mandarin. Follow the links from the abstract to view the translations. This article is commented on by Symonds on pages 549–550 of this issue. [ABSTRACT FROM AUTHOR]