A severe, incurable neurologic disorder thought to affect primarily Arabian horses–cerebellar abiotrophy (CA)–might be able to jump the "breed barrier" and affect other types of horses, according to a University of California, Davis, research team. Other breeds of horses (mostly those with Arabians in their lineage) could be at risk for carrying the CA mutation, which is caused by a mutation on a certain segment of DNA.

Cerebellar abiotrophy is caused by the loss of a specific type of neuron in the cerebellum (the part of the brain that controls a horse’s sensory perception, coordination, and motor control). As a result, affected foals suffer from head tremors and a lack of equilibrium, among other neurologic deficits. Due to the absence of an effective treatment approach the more severely affected foals are routinely euthanized early in life because of the risk they would pose to themselves and others as adults.

Cecilia Penedo, PhD, of the UC Davis Veterinary Genetics Laboratory (VGL), along with Leah Brault, PhD, who worked on the continuing CA project at UC Davis during her doctoral studies, identified a genetic mutation associated with CA in 2010. But they began to wonder if the Arabian’s role in the development of many other breeds could mean that these breeds could have inherited the CA mutation.

Brault and Penedo tested archived DNA samples at the VGL from 1,845 horses of 31 different breeds (not including Arabians) to determine if the CA mutation was present in any other breeds. At least 40 horses from each breed were tested. In