ATP1A3 and optic atrophy: ATP1A3 has been implicated aside to AHC syndrome to other complex syndromes including the Rapid-onset Dystonia-Parkinsonism [6, 19, 20], and the Cerebellar ataxia, Areflexia, Pes cavus, Optic atrophy, and Sensoryneural hearing loss (CAPOS) syndrome [7, 21, 22].