Cerebellar abiotrophy (CA)
CA can appear in pure- and part-bred Arabians. Horses affected by CA can show head tremors, problems with their balance, and exaggerated or erratic leg movements. The age where signs of CA appear and severity of the signs vary a lot. In the best cases, the horse appears normal for several years (or more, in at least one Australian case). In the worst cases an affected foal will be unable to stand without assistance after birth, and will need to be euthanased. Most cases fall between these two extremes, with signs appearing in a weanling or young horse that progressively worsen over a few months or years.
CA is an autosomal recessive disorder. Autosomal disorders are equally likely to affect male or female horses, while "recessive" means that a horse needs to inherit the CA mutation from both its sire and its dam to be affected.
Gene or region and technical reference
Gene: TOE1 (presumed cause). Reference: Brault et al. (2011)
n. Test developed using animal cases.
CA. Test developed using animal controls.