[Genotype and phenotype of children with DEPDC5 gene variants related epilepsy]

Objective: To summarize the clinical characteristics and the features of electroencephalograph (EEG) of children with DEPDC5 gene variants related epilepsy. Methods: The clinical data, gene variation, EEG and head magnetic resonance image (MRI) of 20 epileptic children with DEPDC5 gene variants admitted to Department of Pediatrics, Peking University First Hospital from May 2017 to November 2020 were retrospectively analyzed. Results: Twenty patients with heterozygous DEPDC5 gene variants were enrolled, 8 of 20 patients were nonsense variants, 6 were missense variants, 3 were frame-shift variants, 2 were splicing variants, and 1 was large fragment deletion. Sixteen cases had hereditary variation and 4 had de novo variation. Fifteen of variations were novel. Nine were male, while 11 were female. Their latest follow-up age ranged from 10 months to 13 years and one month.The epilepsy onset age ranged from 3 hours to 11 years and 3 months, the median age was 10.5 months. Twelve (60%) patients had developmental delay. Nineteen patients had focal seizures, 7 had epileptic spasms, 1 had multiple seizure types including tonic, atypical absence, dystonic and myoclonic seizures. Epileptic form discharges were observed in 18 patients during the interictal phase, and 11 were focal discharges, 7 were multifocal discharges. Ten (50%) patients had abnormal brain MRI, including focal cortical dysplasia in 5 patients, undefined malformation of cortical development in 4 patients, hemimegalencephaly in 1 patient. Four patients were diagnosed as West syndrome and one patient was diagnosed as Lennox-Gastaut syndrome. Fourteen (70%) patients were diagnosed as drug-resistant epilepsy. Four patients became seizure-free by treatment with anti-epileptic drugs. Three children were treated with surgery, and 2 of them became seizure-free, 1 had more than 75% reduction in seizures. Conclusions: DEPDC5 gene variant epilepsy is inherited with incomplete penetrance and focal seizure is the major seizure type. However, epileptic spasms, generalized seizures can also be observed. Half of the patients brain malformations. Most of the patients are drug-resistant epilepsy. Patients with clear epileptogenic zones can be treated with surgery. Treatment-resistant patients are more likely to be complicated with developmental delay.