Pharmacological Combination of Sodium Channel Blockers (Oxcarbazepine and Lacosamide) to Control Seizures in Two Patients with Neonatal-Onset Epilepsy due to De Novo SCNA2 Heterozygous Mutation

Objectives: Inherited disorders of the ion channel function (or genetic channelopathies) are a rapidly expanding group of neurological disorders. Current genetic tests have improved the identification, knowledge, and best management of patients affected from these disorders. Mutations in the SCNA2 sodium channel associate with benign familial neonatal infantil epilepsy, neonatal epileptic encephalopathy, and epilepsy infancy with migrating focal seizure (Howell et al, SCN2A encephalopathy: A major cause of epilepsy of infancy with migrating focal seizures. Neurology. 2015).

Content: Methods: Two cases of de novo heterozygous SCNA2 mutation channelopathies were diagnosed in our department in the last year. We reviewed gestational and delivery history, seizure age of onset, seizure semiology, video-EEG, genetic tests, and pharmacological management to control seizures.

Results: The two cases (A and B) onset with epilepsy within the first day of life. No relevant gestational or delivery history was reported. The type of seizure was similar in the two patients, showing autonomic features (apnea episode and cyanosis), arrest behavior, and asymmetric tonic seizure. Patient B also presents clonic seizures in upper extremities. Both patients present many seizure episodes per day with refractory response to initial combination of drugs. Patient A had a normal neurologic examination whereas patient B was diagnosed with epileptic encephalopathy during the firsts days of life. Intercritical pattern of video-EEG showed normal basal activity in both patients with multifocal epileptiform anomalies in patient B. Craneal MRI, infection, and metabolic tests were normal. Clinical exome sequencing test showed a de novo heterozygous mutation in SCN2A in both patients. In both patients, adding lacosamide to oxcarbazepine, a complete seizures control was obtained.

Conclusion: SCN2A mutations are common causes of neonatal genetic epilepsy. The clinical spectrum is wide, from benign familial neonatal epilepsy to epileptic encephalopathy or epilepsy of infancy with migrating focal seizures (EIMFS). The majority of the cases present an initial refractory epilepsy. In our two patients, the combination of two sodium channel blockers (oxcarbazepine and lacosamide) proved to be effective to control seizures.

Publication History

Article published online:
16 March 2022