title: The Genetic Homogeneity of CAPOS Syndrome: Four New Patients With the c.2452G>A (p.Glu818Lys) Mutation in the ATP1A3 Gene.
abstract: The clinical syndrome of cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss (CAPOS) was first described 20 years ago, but it was only recently that whole exome sequencing unveiled the causative mutation in the ATP1A3 gene. We present four patients from the seventh and eighth family identified worldwide, provide a critical review of all patients published thus far, and speculate about the pathophysiologic processes underlying the acute neurological manifestations.
  
  
  
  The individuals presented here experienced one to three paroxysmal, short-lasting episodes in childhood with cerebellar symptoms and signs, hypotonia, ophthalmoparesis, motor weakness, areflexia, and/or lethargy that were consistently associated with febrile illness. An underlying c.2452G>A mutation in the ATP1A3 gene was found in all four individuals. Besides the persisting CAPOS features, other possibly related sequelae included dystonia, myoclonus, and emotional and behavioral changes. After initiation of acetazolamide in two patients, no further episodes occurred.
  
  
  
  Targeted sequencing of the ATP1A3 gene is recommended in children exhibiting paroxysmal, fever-induced ataxia and in adults with a more or less stationary or slowly progressive cerebellar syndrome since childhood accompanied by mixed combinations of areflexia, pes cavus, profound visual impairment, and/or sensorineural hearing loss. Similar to some other types of episodic ataxia, acetazolamide may be considered in patients with CAPOS syndrome to prevent or attenuate bouts of ataxia, but this requires further study.
authors.affiliation: Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands. Electronic address: roderick.maas@radboudumc.nl.
authors.forename: Roderick P P W M
authors.initials: RP
authors.lastname: Maas
authors.affiliation: Department of Pediatric Neurology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Jolanda H
authors.initials: JH
authors.lastname: Schieving
authors.affiliation: Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Meyke
authors.initials: M
authors.lastname: Schouten
authors.affiliation: Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Erik-Jan
authors.initials: EJ
authors.lastname: Kamsteeg
authors.affiliation: Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Bart P C
authors.initials: BP
authors.lastname: van de Warrenburg
mesh_terms: D000328:Adult; D002524:Cerebellar Ataxia / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D005190:Family; D005260:Female; D005532:Foot Deformities, Congenital / Q000235:genetics*; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006801:Humans; D008297:Male; D009896:Optic Atrophy / Q000235:genetics*; D017354:Point Mutation; D012021:Reflex, Abnormal / Q000235:genetics*; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics*
chemical_list: C488756:ATP1A3 protein, human; D000254:Sodium-Potassium-Exchanging ATPase
keywords: ATP1A3 gene; CAPOS syndrome; areflexia; cerebellar ataxia; optic atrophy; pes cavus; sensorineural hearing loss