Objective:To summarize the clinical features of developmental epileptic encephalopathy children with DNM1 gene variants. Methods:The genotypes and clinical features of 15 children with DNM1 variants related epilepsy in the Department of Pediatrics, Peking University First Hospital from June 2017 to October 2021 were retrospectively analyzed. Results:A total of 8 male and 7 female epilepsy patients with DNM1 gene variants with the age of seizure onset ranging from 15 days to 22 months were recruited, median age was 8 months.All cases belonged to de novo heterozygous variants of the DNM1 gene, including 13 cases of missense variants, 1 case of frame shift variant and 1 case of nonsense variant, 8 cases of ectopic sites have not been reported.Multiple seizure types were observed, including epileptic spasms in 15 patients, focal seizure in 9 patients, atypical absence seizure in 2 patients and tonic seizure in 2 patients.There were various types of seizures in 7 children.Nine cases occurred as infantile spasm for the first time.All 15 patients showed varied degrees of development delay, among them, 11 cases had developmental retardation before epilepsy.Three patients had slow rhythm of electroencephalogram background activity, the electroencephalography showed hypsarrhythmia in 13 patients; clinical seizures were detected in 8 cases, among them, epileptic spasms were captured in 7 patients, tonic seizure was captured in 1 patient.Widened frontotemporal subarachnoid space, cerebral atrophy, and corpus callosum dysplasia were examined in 6, 2 and 3 patients by cranial magnetic resonance imaging, respectively.All 15 cases were diagnosed as developmental epileptic encephalopathy, of which 13 cases were consistent with infantile spasms.The age of the last follow-up ranged from 1 year old to 7 years old.After multi-antiepileptic drug treatment, 2 patients were remission, 1 patient(small size of identical twins) died of severe pneumonia at the age of 2 years, and 12 patients still had intermittent seizures, of which 1 patient was transformed from infantile spasms to Lennox-Gastaut syndrome. Conclusions:The onset age of developmental epileptic encephalopathy caused by the DNM1 gene variant usually begins in the infantile period, the peak onset age was 8 months.The main types of seizures include epileptic spasms and focal seizures, developmental retardation can occur before seizures.The clinical manifestations are mostly infantile spasms syndrome, and some children can be transformed into Lennox-Gastaut syndrome.

Objective:To summarize the genotype and clinical phenotype of children with WWOX gene related developmental and epileptic encephalopathy (DEE).Methods:Case series studies. The clinical data of 12 children with WWOX gene related DEE who were admitted to the Neurological Department of Children′s Medical Center, Peking University First Hospital from June 2019 to December 2023 were analyzed. The children′s characteristics of gene variation, clinical phenotype, auxiliary examination results, treatment and prognosis were analyzed.Results:Among 12 children with WWOX gene related DEE, there were 7 boys and 5 girls, the age of seizure onset ranged from 10 days to 6 months (median 1.8 months). Multiple seizure types were observed, including focal seizures in 10 cases, epileptic spasms in 9 cases, tonic seizures in 4 cases, myoclonic seizures in 1 case. Among 12 cases, 9 cases had multiple seizure types. All 12 cases showed microcephaly and global developmental delay. Video electroencephalography showed slowed background activity in 6 cases, hyperarrhythmia in 6 cases, multifocal discharges in 6 cases, and focal discharges in 1 case. Epileptic spasms were detected in 8 cases, tonic seizures in 4 cases and myoclonic seizures in 1 case. Brain magnetic resonance imaging showed bilateral frontotemporal subarachnoid space widening in 5 cases, deep sulci in 3 cases, bilateral ventricular enlargement in 2 cases, callosal hypoplasia in 5 cases, and delayed white matter myelination in 3 cases. The phenotypes of 12 cases were consistent with the diagnosis of DEE, and 8 of them were diagnosed with infantile epileptic spasm syndrome. All the WWOX gene variants in 12 cases were complex heterozygous variants, including 20 variants, 11 variants and 1 large intragenic WWOX gene deletion (p.Ala149Thr, p.Arg156Ser, p.R167Tfs*8, p.Leu186Val, c.605+5G>A, p.Trp218*, p.His263Arg, p.Leu275fs*19*1, p.N285Kfs*10, p.Ser304Tyr, p.Met326Arg, loss1 exon2-8) had not been reported previously. The age of last follow-up ranged from 11 months to 5 years and 3 months. During the follow-up, 1 case died at the age of 1 year and 10 months, 2 cases were seizure-free, and 9 cases still had seizures after multiple anti-seizure medications.Conclusions:The seizure onset age of children with WWOX gene related DEE is usually less than 6 months, and some of them in neonate. The common seizure types include focal seizures and epileptic spasms. Children usually have microcephaly and global developmental delay. WWOX gene related DEE usually has drug refractory epilepsy.

Objective:To summarize the clinical features of epilepsy and (or) developmental delay associated with KCNB1 gene variants in children.Methods:A case series study was conducted on 24 children with KCNB1 gene variants associated with epilepsy and (or) developmental delay who were treated at the Children′s Medical Center of Peking University First Hospital and the Department of Neurology of Shenzhen Children′s Hospital from July 2015 to June 2024. The manifestations of seizures, electroencephalogram (EEG) and genetic test results of those children were analyzed.Results:All the KCNB1 gene variants were de novo, involving 20 different variation, including 15 missense variations, 3 frameshift variations and 2 nonsense variations. There were 7 novel variations. Among the 24 developmental and epileptic encephalopathy children, there were 14 boys and 10 girls. The last follow-up age ranged from 9 months to 13 years and 9 months. Seizures were present in 21 children (88%), with onset ranging from 1 month to 7 years, and 76% (16/21) began before 2 years of age. The seizure types included focal seizures in 15 children (71%), epileptic spasms, myoclonic seizures, and generalized tonic-clonic seizures in 6 children respectively, atypical absence seizures in 4 children, and myoclonic atonic seizures in 1 child. Seventeen children (81%) had a cluster of seizures and 5 had a history of focal status epilepticus with impaired consciousness. All 24 children had varying degrees of developmental delay, with 3 presenting solely developmental delay. EEG abnormalities were present in all the 21 children with seizures, including focal or multifocal discharges in 20 children, generalized discharges in 10 children, hypsarrhythmia in 2 children, and electrical status epilepticus during sleep in 3 children. Magnetic resonance imaging abnormalities were found in 5 of the 24 children. Among the 21 children with seizures, 57% (12/21) achieved seizure control.Conclusions:KCNB1 gene variants are predominantly de novo missense variation. Most affected children present with epilepsy, though some may exhibit only developmental delay. Epilepsy often begins before 2 years of age, with focal seizures being the most common type. About 80% of patients experience clustered seizures. Although most patients achieve seizure control, they still exhibit varying degrees of developmental delay, consistent with developmental epileptic encephalopathy.