Mutations in ATP1A2 (AHC1; OMIM#104290) and ATP1A3 (AHC2; OMIM#614820), which encode two different alpha subunits of the neuronal NA+-K+ ATPase transmembrane ion pump, are the most frequent involved genes.[7–10] AHC individuals with ATP1A3 mutations are numerically more common than those with ATP1A2 mutations.[11] The wider use of genetic technology has enabled it to differentiate AHC diagnosis from other similar disorders and to extend its clinical spectrum. Here, ATP1A3 is linked to alternating hemiplegia of childhood.