title: The frequency of the equine cerebellar abiotrophy mutation in non-Arabian horse breeds.
abstract: BACKGROUND
  A putative mutation causative of cerebellar abiotrophy (CA), a genetic defect found almost exclusively in Arabian horses, was recently identified.
  
  
  OBJECTIVE
  To investigate the presence of the CA mutation in breeds other than Arabian and ascertain whether the mutation had been introduced into these breeds by Arabian ancestry. The CA mutation is present in breeds of horses with Arabian ancestry.
  
  
  METHODS
  Allele-specific PCR was used to genotype 1845 non-Arabian horses for the CA mutation. For those breeds in which at least one carrier was identified, an additional 266 horses were genotyped to determine the frequency of the CA allele. Cerebellar abiotrophy carriers were further genotyped for a haplotype segregating with CA in Arabians.
  
  
  RESULTS
  At least one CA carrier was identified in 3 breeds and the frequency of the CA allele calculated: Bashkir Curly Horses (2.8%), Trakehners (0.68%) and Welsh ponies (0.33%). Based on pedigree and haplotype analysis, CA was introduced into these breeds by Arabian ancestry. The Trakehner and Welsh pony carriers were at least half-Arabian, while the Bashkir Curly horses appeared to have had the CA allele introduced by a single Arabian stallion used for developing the breed in the 1960s.
  
  
  CONCLUSIONS
  The CA mutation is present in breeds of horses that allow crossbreeding with Arabian horses and in breeds that have used Arabians as foundation stock during their development.
  
  
  CONCLUSIONS
  Breeds that allow registration of horses with Arabian ancestry should have any Arabian breeding stock tested for the mutation and breeds descended from Arabian ancestry should pursue genetic testing of breeding stock to prevent the occurrence of affected foals.
authors.affiliation: Veterinary Genetics Laboratory, University of California-Davis, One Shields Ave., Davis, CA 95616, USA.
authors.forename: L S
authors.initials: LS
authors.lastname: Brault
authors.forename: M C T
authors.initials: MC
authors.lastname: Penedo
mesh_terms: D000818:Animals; D005838:Genotype; D020271:Heredodegenerative Disorders, Nervous System / Q000235:genetics / Q000662:veterinary*; D006734:Horse Diseases / Q000235:genetics*; D006736:Horses; D009154:Mutation