Cerebellar Abiotrophy - Cerebellar Abiotrophy in Horses

Cerebellar Abiotrophy in Horses

Cerebellar abiotrophy (CA) is best known as a condition affecting Arabian horses. It has also been observed in the Miniature horse, the Gotland Pony, one Eriskay Pony, and possibly the Oldenburg. Most foals appear normal at birth, with symptoms noticeable at an average age of four months, though there have been cases where the condition is first seen shortly after birth and other cases where symptoms are first recognized in horses over one year of age.

In horses, CA is believed to be linked to an autosomal recessive gene. This means it is not sex-linked, and the allele has to be carried and passed on by both parents in order for an affected animal to be born. Horses that only carry one copy of the gene may pass it on to their offspring, but themselves are perfectly healthy—without symptoms of the disease. Because it is recessive, the allele for CA may pass through multiple generations before it is expressed.

CA is sometimes misdiagnosed. Though the symptoms are quite distinguishable from other neurological conditions, it has been confused with Wobbler's syndome, Equine Protozoal Myeloencephalitis (EPM), and injury-related problems such as a concussion.

A DNA test which identifies markers associated with cerebellar abiotrophy is available. The test has been refined to identify the most likely mutations, and retesting of earlier samples based on an earlier indirect marker test developed by UCD, indicated a 97% accuracy rate for the old test relative to the newer version, with no false negatives. Continued research is taking place at the Veterinary Genetics Laboratory at the UC Davis School of Veterinary Medicine. Researchers working on this problem include Dr. Cecilia Penedo, PhD, and Leah Brault, PhD. The late Dr. Ann Bowling also made significant contributions to the genetics research on CA.