ATP1A3 and alternating hemiplegia of childhood: Relevant etiopathogenetic role in AHC is linked to mutations in ATP1A2 (AHC-1; OMIM#104290) and in ATP1A3 genes (AHC-2; OMIM#614820), respectively which encode two different alpha subunits of the Na+/K+ ATPase transmembrane ion pump [9, 10].