ATP1A2 and Intellectual disability: Besides FHM2,6 the clinical spectrum of ATP1A2 ranges from migraine with or without aura, intellectual disability, and seizures in ∼15% of the cases, including benign familial infantile convulsions and generalized epilepsy with febrile seizures.7-9,14 Two ATP1A2 germline variants were also identified in patients with alternating hemiplegia of childhood.15