Abstract: Objective To analyze the clinical and genetic characteristics of epilepsy with myoclonic-atonic seizure caused by CACNA1 H gene mutation. Method Clinical analysis, laboratory examination and gene sequencing of a case of drug-resistant epilepsy with myoclonic-atonic seizure were retrospectively analyzed. Results At the age of 1 year, the patient had febrile convulsions. At the age of 2 years and 4 months, he had myoclonus, atonic and absence seizures, accompanied by developmental delay. Multiple antiepileptic drugtreatment is ineffective. Finally, he was responsive to lamotrigine. A novel heterozygous variation c. 3633 G > A (p.R 1215 H) in CACNA1H gene was found. According to the guidelines of American Society of Medical Genetics and Genomics, the variation was rated as likely pathogenic, which was consistent with autosomal dominant inheritance. Conclusion This study expanded the genotype of epilepsy with myoclonic-atonic seizure, which is of great significance for the precise treatment of refractory epilepsy.

Key words: epilepsy with myoclonic-atonic seizure; CACNA1 H gene; lamotrigine