GOSR2 and progressive myoclonus epilepsy: In conclusion, we report a genotypic and phenotypic expansion of GOSR2-associated NS-PME in a patient with early-onset disease and refractory epilepsy likely due to disrupted interaction with the COPII-coated vesicle machinery, and another patient with disease onset during adolescence, seizure remission on levetiracetam, and retained cognitive function during the third decade of life.