INTRODUCTION: Dravet Syndrome (DS) is an epileptic encephalopathy. It begins with febrile seizures, and then adds different types of seizures which are refractory to treatment. In more than 70% of cases a mutation in the voltage dependent sodium channel (SC-N1A) is identified. OBJECTIVE: Describe the clinical and electrophysiological characteristics of 4 patients with DS genetically confirmed.MATERIALS AND METHODS: Descriptive retrospective analysis of medical histories, EEG and genetic studies with prospective follow-up.RESULTS: 4 patients, 4/4 normal development before seizures, ¼ epilepsy in family. First seizure occurred between 4-6 months, ¾ were febrile, ¾ lasted over 15 minutes. 4 patients had all kinds of seizures except for tonic, being partial secondary generalized, myoclonic and complex-partial seizures the most frequents. 4 patients have refractory epilepsy with frequent status. 2/4 worsen seizures with Lamotrigine. All evolve with a moderate-severe developmental delay, ¾ with ataxia, 2/4 with pyramidalism, ¾ with autistic behavior. All had normal EEGs during first year of life, evolving with focal-multifocal activity and disorganized background activity. Photosensitivity (+) ¼. Normal brain MRI ¾, ¼ with diffuse cortical atrophy. All cases had punctual heterozygous mutations in exons 4,17 and introns 5,22 of SCN1A gene.DISCUSSION: One of the first national reports of the experience on molecular diagnosis of SD.CONCLUSION: The 4 patients had the punctual mutations of SCN1A gene, they all presented the classic presentation of DS.