Phenotype study of SCN2A gene related epilepsy / 中华儿科杂志

ABSTRACT

Objective@#To summarize the phenotype of epileptic children with SCN2A mutations.@*Methods@#Epileptic patients who were treated in the Pediatric Department of Peking University First Hospital from September 2006 to October 2017 and detected with SCN2A mutations by targeted next-generation sequencing were enrolled. Clinical manifestations of all patients were analyzed retrospectively.@*Results@#A total of 21 patients (16 boys and 5 girls) with SCN2A mutations were collected. Twenty-one SCN2A mutations were identified. Ten patients had mutations inherited from one of their parents and 11 patients had de novo mutations. The age of epilepsy onset was from 2 days to 2 years and 6 months six patients with seizure onset in neonates (29%) , six patients with seizure onset between 1 month and 3 months of age (29%), three patients with seizure onset between 4 months and 6 months of age, two patients with seizure onset between 7 months and one year of age, and four patients with seizure onset beyond one year of age. Multiple seizure types were observed. The focal seizure was the most common seizure type which was observed in 18 patients (86%) . Spasm seizure was observed in 6 patients (29%) . Other seizure types were rare. In 19 patients, seizures manifested in clusters (90%) . In 3 patients, seizures manifested fever-sensitive. Nine of ten patients with inherited SCN2A mutations had normal development. However, all patients with de novo SCN2A mutations had mild or severer development delay. In 21 patients with SCN2A mutations, five were diagnosed with benign familial infantile epilepsy, 3 with benign familial neonatal-infantile epilepsy, 3 with Ohtahara syndrome, 3 with West syndrome, 2 with encephalopathy with early infantile onset epilepsy, one with febrile seizures plus, one with Dravet syndrome, one with encephalopathy with childhood-onset epilepsy, one with autism with epilepsy and one with intellectual disability with epilepsy.@*Conclusions@#The clinical features of patients with SCN2A mutations include that main seizure onset is the neonate and early infancy, and the main seizure type is the focal seizure, manifested in clusters. The large spectrum of SCN2A-related epilepsy, which not only includes epilepsy with a comparatively favorable prognosis, but also epileptic encephalopathy. De novo mutations often lead to severe phenotype with development delay.