The frequency of the equine cerebellar abiotrophy mutation in non-Arabian horse breeds.
Authors: Brault L S, Penedo M C T
Journal: Equine veterinary journal
Summary
# Editorial Summary: Cerebellar Abiotrophy Beyond Arabian Horses Cerebellar abiotrophy (CA) has long been recognised as a genetic disorder almost exclusively affecting Arabian horses, but the recent identification of its causative mutation has revealed a broader problem: the defect is now present in multiple other breeds through Arabian ancestry. Brault and Penedo used allele-specific PCR to screen 1845 non-Arabian horses for the CA mutation, then conducted haplotype analysis on carriers to determine whether the mutation had been inherited from Arabian bloodlines. The researchers identified CA carriers in three breeds—Bashkir Curly Horses (2.8% allele frequency), Trakehners (0.68%) and Welsh ponies (0.33%)—with pedigree analysis confirming that Arabian genetics introduced the mutation into each breed, whether through recent half-Arabian crosses or historical foundation stock from the 1960s onwards. Veterinarians and stud managers should recognise that any breed permitting Arabian crossbreeding or descended from Arabian foundation horses now carries risk, making pre-breeding genetic screening of Arabian stock essential to prevent the birth of clinically affected foals in these expanding carrier populations.
Read the full abstract on PubMed
Practical Takeaways
- •If your breeding programme includes Arabian ancestry or Arabian crosses, genetic testing for the CA mutation should be mandatory for breeding stock to prevent affected foals
- •Breeds with known Arabian foundation ancestry (Bashkir Curly, Trakehner, Welsh pony) carry CA risk; verify carrier status before breeding decisions
- •Implement breed-specific testing recommendations for any breed allowing Arabian registration or crossbreeding to identify and manage carriers in your operation
Key Findings
- •CA mutation identified in 3 non-Arabian breeds: Bashkir Curly Horses (2.8% allele frequency), Trakehners (0.68%), and Welsh ponies (0.33%)
- •CA was introduced into these breeds through Arabian ancestry, either via direct Arabian crossbreeding or use of Arabian foundation stock
- •Trakehner and Welsh pony carriers were at least half-Arabian; Bashkir Curly horses acquired the mutation from a single Arabian stallion used in breed development during the 1960s
- •The mutation is present in horse breeds that allow or have used Arabian crossbreeding, indicating need for genetic testing protocols in Arabian breeding stock