Epilepsy with eyelid myoclonia in a patient with <i>ATP1A3</i>‐related neurologic disorder

We report on an 11 year old Polish girl who experienced paroxysmal episodes with decreased consciousness, (hemi)plegia, movement disorders, slurred speech, dysphagia, and abnormal eye movements. An extensive etiological work-up (brain MRI, EEG, EMG, NCS, toxic, metabolic, infectious, and auto-immune screening) was not conclusive. A genetic analysis with whole-exome sequencing demonstrated a de novo heterozygous mutation in the ATP1A3 gene (c.2232C>G, p.Asn744Lys). A 48 h video-EEG monitoring that was conducted in our unit later confirmed the absence of ictal discharge during an episode of hemidystonia, demonstrating its non-epileptic etiology. However, several discharges of generalized spike waves, which were facilitated by intermittent photic stimulation and eyelid closure were recorded, of which a few were associated with eyelid myoclonia. Taken together, these findings are characteristic of epilepsy with eyelid myoclonia. The clinical picture of this patient partially fulfills the diagnostic criteria of relapsing encephalopathy with cerebellar ataxia as well as alternating hemiplegia of childhood. It is increasingly recognized that the distinct syndromes described with ATP1A3 mutations are overlapping and could be identified in the same patients. Certain variations in ATP1A3 have been linked to an increased risk of developing generalized epilepsy syndromes. We hereby present the second case in the literature of a patient with epilepsy with eyelid myoclonia with an ATP1A3-related neurological disorder.