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Cerebellar ataxia, areflexia, pes cavus, optic atrophy and sensorinural hearing loss


Other Names:
CAPOS; CAPOS syndrome; Cerebellar ataxia - areflexia - pes cavus - optic atrophy - sensorineural hearing loss; CAPOS; CAPOS syndrome; Cerebellar ataxia - areflexia - pes cavus - optic atrophy - sensorineural hearing loss; Cerebellar ataxia-areflexia-pes cavus-optic atrophy-sensorineural hearing loss syndrome See More
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Cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss (CAPOS) syndrome is a neurological disorder. The syndrome gets its name from the different parts of the body it usually affects:[1][2][3]
CAPOS syndrome typically begins after a fever-related illness with a sudden episode of ataxia, such as having a hard time walking or coordinating leg or arm movements. The ataxia is usually associated with generalized weakness and/or inflammation of the brain (encephalopathy). The first episode most often happens between the ages of 6 months and 5 years.[1][2] Pregnancy and delivery may also trigger episodes.[3] Most people with CAPOS syndrome have one to three episodes during their lifetime.[2] Other signs and symptoms during an episode may include low muscle tone, unusual eye movements (nystagmus or strabismus), problems with speech (dysarthria), difficulty swallowing (dysphagia), reduced or absent reflexes, and hearing loss. Some people may lose consciousness or go into a coma during an episode. Though many of the signs and symptoms of CAPOS syndrome get better as the fever and illness improve, some symptoms, including movement problems, may continue. Vision changes (optic atrophy) and sensorineural hearing loss tend to worsen over time, although the severity and rate of progression varies.[1][2][3] Long-term management may include physical therapy, hearing and vision aids, and regular exams to check for changes in vision, hearing, and muscle coordination.[1] 

Last updated: 12/19/2017

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Areflexia
Absent tendon reflexes
0001284
Ataxia 0001251
Encephalopathy 0001298
Muscle weakness
Muscular weakness
0001324
Optic atrophy 0000648
Sensorineural hearing impairment 0000407
5%-29% of people have these symptoms
Abnormality of eye movement
Abnormal eye movement
Abnormal eye movements
Eye movement abnormalities
Eye movement issue
[ more ] 		0000496
Autistic behavior 0000729
Cognitive impairment
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment
[ more ] 		0100543
Dysphagia
Poor swallowing
Swallowing difficulties
Swallowing difficulty
[ more ] 		0002015
Dystonia 0001332
Pes cavus
High-arched foot
0001761
Seizure 0001250
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance 0000006
Blindness 0000618
Dysarthria
Difficulty articulating speech
0001260
Dysmetria
Lack of coordination of movement
0001310
Episodic generalized hypotonia 0006852
Gait ataxia
Inability to coordinate movements when walking
0002066
Hemiparesis
Weakness of one side of body
0001269
Incoordination
Difficulties in coordination
Incoordination of limb movements
Limb incoordination
[ more ] 		0002311
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Progressive sensorineural hearing impairment 0000408
Progressive visual loss
Progressive loss of vision
Progressive vision loss
Progressive visual impairment
Slowly progressive visual loss
Vision loss, progressive
Visual loss, progressive
[ more ] 		0000529
Truncal ataxia
Instability or lack of coordination of central trunk muscles
0002078
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Last updated: 7/1/2020
CAPOS syndrome is caused by specific changes (mutations) in the ATP1A3 gene. These changes can be inherited in an autosomal dominant manner or may happen by mistake during the formation of the egg or the sperm (de novo). Diagnosis is usually suspected based on symptoms and the results of a brain MRI and muscle and nerve tests (EMG evaluations). Testing to evaluate changes in the optic nerve and nerves involved in hearing may offer additional support. The diagnosis of CAPOS syndrome is confirmed by genetic testing.[1][2][3]

Other syndromes that may also be caused by different changes or mutations in the ATP1A3 gene include rapid-onset dystonia-parkinsonism (RDP) and alternating hemiplegia of childhood (AHC).[1][3] In some cases the signs and symptoms of these syndromes may overlap.[3]
Last updated: 12/19/2017

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Cerebellar ataxia, areflexia, pes cavus, optic atrophy and sensorinural hearing loss. Click on the link to view a sample search on this topic.

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  1. Brashear A, Sweadner KJ, Cook JF, et al. ATP1A3-Related Neurologic Disorders. GeneReviews. November 6, 2014; https://www.ncbi.nlm.nih.gov/books/NBK1115/.
  2. Chang IJ, Adam MP, Jayadev S, Bird TD, Natarajan N, Glass IA. Novel pregnancy-triggered episodes of CAPOS syndrome. Am J Med Genet. November 1, 2017; https://www.ncbi.nlm.nih.gov/pubmed/29090527.
  3. Duat Rodriguez A, Prochazkova M, Santos Santos S, Rubio Cabezas O, Cantarin Extremera V, Gonzalez-Gutierrez-Solana L. Early Diagnosis of CAPOS Syndrome Before Acute-Onset Ataxia-Review of the Literature and a New Family. Pediatr Neurol. June, 2017; 7160-64:https://www.ncbi.nlm.nih.gov/pubmed/28483396.