Mutations in the ATP1A3 gene are associated with three related rare neurological disorders, rapid-onset dystonia-parkinsonism (RDP)1, alternating hemiplegia of childhood (AHC)2, 3, and recently, cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss (CAPOS) syndrome4. This evidence concerns the gene ATP1A3 and nervous system disorder.