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Cerebellar Abiotrophy (CA)


→ Ataxia due to progressive death of brain cells responsible for movement.

Instructions for ordering:

  1. Enter the information of the first horse for which you want to order the test
  2. Add to cart
  3. Go to cart to check out, or
  4. Enter the information for a second horse
  5. For sample collection follow the instructions here.
  6. You can use this template to send in hair samples.
  7. Please also send the completed order form together with the samples.

For a breeder or veterinarian discount please contact us before ordering.

Breeder Information (Germany): Beginning January 2019, all active riding pony stallions in Germany must be tested for CA to be approved for breeding.

Any information you include here is optional, but will be included on the certificate of results (except “Additional info”).

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Enter your animal's date/year of birth
Enter the breed name
Enter the registration number if known
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Is there anything else you would like to tell us about your horse? Reason for testing, symptoms etc.?

General Information

  • Degeneration of Purkinje cells in cerebellum, with first symptoms visible as early as six weeks of age.
  • Strongly variable severity of symptoms may impede diagnosis.
  • Risk of injury is high for affected horse and handler → should be handled very carefully and not be used for riding/sports.
  • Affected horses are often euthanized due to poor quality of life.
  • The mutation is found in Arabians, German Riding Ponies and related breeds.  Because of the wide use of Arabian horses in many other breeds, it is recommended that riding ponies and light horses of many breeds be tested.  Beginning January 2019, all active riding pony stallions in Germany must be tested to be approved for breeding.


  • Balance and coordination issues
  • Head tremors
  • Occasional falling/stumbling
  • Difficulties rising
  • Wide-based stance
  • Uncontrolled/overshooting movements

Inheritance and Genotypes

→ CA is an autosomal recessive hereditary disease, meaning that horses with only one copy of the genetic variant (N/ca) are clinically normal carriers while horses with two copies of the genetic variant (ca/ca) are affected.

Genotype: The horse is: Effects:
N/N normal. The horse does not have any copies of the genetic variant causative for CA and therefore cannot pass it on to any offspring.
N/ca a carrier. The horse is clinically healthy. It has one copy of the genetic variant causitive for CA, which will be passed on to its offspring with a probability of 50%.
ca/ca affected. The horse has two copies of the genetic variant causitive for CA. The variant will be passed on to all offspring. All offspring will be carriers (N/ca).


  • Carriers may be bred to normal animals (N/ca x N/N) without any risk of producing affected offspring. The offspring should also be tested before breeding to determine if they are carriers or normal.
  • Breeding two carriers (N/ca x N/ca) is not recommended due to the possibility of 25% of the offspring being affected.
  • Affected animals (ca/ca) should not be used for breeding.


Brault, L.S., Cooper, C.A., Famula, T.R., Murray, J.D. and Penedo, M.C.T. (2010) Mapping of equine cerebellar abiotrophy to ECA2 and identification of a potential causative mutation affecting expression of MUTYH. Genomics doi: 10.1016/j.ygeno.2010.11.006.

Further information is available at Online Mendelian Inheritance in Animals.

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