Equine Juvenile Spinocerebellar Ataxia (EJSCA)

Description

Equine Juvenile Spinocerebellar Ataxia (EJSCA) is a inherited neurological disorder affecting young horses, characterized by progressive incoordination and loss of balance. Testing for this condition is now included across all relevant genetic screening panels to help breeders identify carriers and prevent the disease in future offspring.

What is Equine Juvenile Spinocerebellar Ataxia (EJSCA)?

Equine Juvenile Spinocerebellar Ataxia (EJSCA) is a severe genetic condition that affects the horse's central nervous system—specifically the cerebellum and spinal cord—which coordinate motor control and balance.

• Symptoms: Affected foals typically present within the first few months to a year of life. Common signs include gait abnormalities, severe clumsiness (ataxia), loss of balance, intention tremors, and a wide-based stance.

• Progression: The disorder is progressive. As the ataxia worsens, affected animals become increasingly uncoordinated and eventually lose the ability to stand or navigate safely.

• Inheritance Pattern: EJSCA is inherited as an Autosomal Recessive trait. A horse must inherit two copies of the mutated gene (one from each parent) to be clinically affected by the disease.

Understanding Your Test Results

Genetic testing identifies whether a horse carries the mutated gene responsible for EJSCA. Because it follows an autosomal recessive inheritance model, results will fall into one of three categories:

Breeding Recommendations

To prevent producing affected foals:

• Clear $\times$ Clear (N/N $\times$ N/N): 100% of offspring will be Clear (N/N).

• Clear $\times$ Carrier (N/N $\times$ N/EJSCA): 50% Clear (N/N), 50% Carrier (N/EJSCA). No foals will be affected.

• Carrier $\times$ Carrier (N/EJSCA $\times$ N/EJSCA): Avoid this pairing. There is a 25% chance of producing an affected foal (EJSCA/EJSCA), a 50% chance of a carrier, and a 25% chance of a clear foal.

By including EJSCA testing in our standard equine panels, breeders can make informed, responsible pairing decisions to completely eliminate the risk of producing affected foals.