Researcher: Genetic Mutation Likely the Cause of Neurologic Disorder

Researchers at the University of California, Davis, have recently identified a genetic mutation associated with the disorder cerebellar abiotrophy (CA). This debilitating neurologic disorder causes the degeneration of the cerebellum, and mainly affects Arabian horses.

The cerebellum is the part of the brain that plays an important role in the integration of sensory perception, coordination, and motor control. Cerebellar abiotrophy results from the loss of a specific type of neuron (known as Purkinje cells) in the cerebellum, causing head tremors and a lack of balance equilibrium, among other neurologic deficits. Unfortunately, there is no treatment. The more severely-affected foals are routinely euthanized before adulthood because of the risk they pose to themselves and others.

Cecilia Penedo, PhD, of the UC Davis Veterinary Genetics Laboratory, along with Leah Brault, PhD, who worked on the CA project during her doctoral studies, were recently able to identify a mutation in the DNA of horses with CA that they believe could be responsible for causing the disorder.

"The mutation we've identified is in a location of two overlapping genes," Penedo said. "It's an interesting feature of the DNA architecture in that region."

"We're working to get solid data about which of the two overlapping genes is affected by that mutation," she continued. "There's some indication that it affects the expression of one of the genes. We want to expand on that work and also explore the changing expression of the other gene."

"This is an important finding as it moves the currently available CA test from a marker based screening test to a more fully developed DNA test," the Arabian Horse Association said in a statement. "The current test allows breeders to test foals suspected of having CA, and allows them to find carriers of the recessive traits in their herd of breeding stock. The true value of testing is to help guide breeders in making safe mating selections, with the goal to never produce a CA affected foal."

About the Author

Erica Larson, News Editor

Erica Larson, news editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

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