ATP1A3 mutations can also cause allelic disorders such as rapid-onset dystonia-parkinsonism (DYT12, OMIM #128235) and cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss (CAPOS syndrome, OMIM #601338) [46]. Here, ATP1A3 is linked to Areflexia.