Dravet Syndrome: An Electroclinical, Genetic, Treatment, and Outcome Study of 35 Patients in Argentina

Abstract

We analyzed the electroclinical features, molecular findings, treatment, disease course,and outcomes of patients with Dravet syndrome (DS) with positive genetic markersseen at a public hospital in Argentina. A retrospective study was conducted assessingthe clinical records of 44 patients who met the diagnostic criteria for DS according tothe 2022 classification of epilepsy of the International League Against Epilepsy seen atour center between March 2018 and June 2023. Of 44 patients, 35 (18 males and 17females), in whom genetic studies yielded positive results, were included. Median agewas 9 years (range 4 to 16 years), and the median time of follow-up was 10 years (range3 to 14 years). The mean age at onset was 7 months. The first seizure was associatedwith febrile illness in all patients, and in 11 (31.4%), seizures were immediatelypreceded by either infectious disease or vaccination. Heterozygous pathogenic/likelypathogenic SCN1A variants were detected in 32 of the original 44 patients (73%), ofwhich 47% were novel. Variants in other genes related to DS (HCN1, STXB1, and SCN1B)were identified in three patients. Cognitive delay and motor impairment were found tobe more severe in patients that had multiple and drug-resistant seizures and in thosewho had the complete phenotype with myoclonic seizures. Novel SCN1A gene variantswere identified in nearly half of the patients. The prognosis for cognitive developmentis unfavorable. Seizures are not well controlled with antiseizure medications and earlytreatment with ketogenic dietary therapy as well as cannabidiol should be considered.