CACNA1A-related early-onset encephalopathy with myoclonic epilepsy: A case report.

We report a one-year-old boy with early-onset myoclonic epilepsy, developmental arrest, and hyperekplexia during early infancy. He presented with refractory myoclonic/tonic seizures since birth. Electroencephalography revealed multifocal spikes, and rhythmic activities that occurred simultaneous with aggravation of myoclonus accompanied by tonic upper limb elevation. Brain magnetic resonance imaging revealed progressive cerebral atrophy with periventricular signal change and thin corpus callosum at one year of age. A de novo heterozygous missense mutation in the CACNA1A gene was confirmed. This patient was the most severe phenotype of CACNA1A-related early-onset encephalopathy among previous reports.