ATP1A3 and cerebellar ataxia: Similarly, a patient with a de novo heterozygous variant of ATP1A3 (c.2452G>A; p.Glu818Lys) causative of CAPOS syndrome showed a fever-induced episode of marked chorea, ataxia, flaccid tetraplegia with areflexia, and nystagmus at the age of four years [84].