Complex paroxysmal episodes of dystonic-tonic posturing with eye movement abnormalities should raise suspicion of an ATP1A3-related disorder, while paroxysmal tonic episodes alternating with hypotonia have been documented in SCN8A. Outside these conditions, data to set up the diagnostic process since the first days of life mainly pertain to the epilepsy phenotype, in some cases assisted by neuroimaging data. The gene discussed is ATP1A3; the disease is epilepsy.