Since ATP1A3 mutations were reported in patients with AHC in 2012, the increasing numbers of patients with overlapping or unique phenotypes have led to use of the broader term “ATP1A3-related neurologic disorders.” However, it is notable that, to date, patients with the classically described phenotypes associated with AHC and RDP share very little overlap in the precise mutations identified. This evidence concerns the gene ATP1A3 and alternating hemiplegia of childhood.