2022 Volume 14 Issue 1 Pages 17-24
Mutations of SCN2A (which encodes the voltage-gated sodium channel Nav1.2) cause different types of epilepsy and neurodevelopmental disorders. In this report, we present a case of epilepsy of infancy with migrating focal seizures (EIMFS) caused by a novel SCN2A missense mutation with mosaicism. From the second day of life, a full-term male infant with no perinatal abnormalities developed frequent focal seizures with symptoms that include apnea, ocular deviation, and brief tonic seizures. Based on electroencephalographic findings during an ictal phase, he was diagnosed with EIMFS. The epilepsy was resistant to several antiepileptic drugs, and phenytoin was the only effective medication. Whole-exome sequencing analysis revealed a de novo SCN2A missense mutation (c.488C>T, p.Thr163Ile) with mosaicism of about 15%. Thus, we concluded that physicians should accurately determine the genes to analyze based on medical history and that mosaicism should be considered during genetic analysis.
