Equine Juvenile Spinocerebellar Ataxia (EJSCA) is a newly discovered genetic disorder. Identified in 2024 by Dr. Carrie Finno and her team at the University of California, Davis, EJSCA causes severe neurological decline in foals and ultimately leads to euthanasia, as affected horses become unable to stand or function independently. However, EJSCA is entirely preventable with informed breeding practices.
What Is EJSCA?
EJSCA stands for Equine Juvenile Spinocerebellar Ataxia. It is a recessive genetic disorder that disrupts the function of the spinocerebellar tract, a critical part of the nervous system responsible for coordination and movement. Foals born with two copies of the mutated gene (JSA/JSA) begin to show symptoms within a few weeks of life, often appearing uncoordinated or unsteady. These signs quickly progress, with affected foals losing the ability to stand or walk.
There are no treatment or management options for EJSCA. Once symptoms appear, the only humane option is euthanasia. Due to this, detection through genetic testing of breeding stock is crucial. Genetic testing is critical for responsible breeders who want to protect their foals.
Carrier Status and Inheritance Risk
A foal will only develop EJSCA if it inherits two copies of the defective gene, one from each parent. Horses that carry one copy of the EJSCA gene mutation (N/JSA) are called carriers. These horses are clinically normal and show no outward signs of disease, making it impossible to detect carrier status without genetic testing.
If two carrier horses are bred together, there’s a 25% chance their foal will have EJSCA, a 50% chance the foal will be a carrier, and only a 25% chance the foal will be completely free of the mutation.
How Owners and Breeders Can Avoid EJSCA in Foals
The most effective and currently only way to prevent EJSCA is to avoid breeding with two carriers. Thanks to the work of Dr. Finno and the team at the University of California, Davis, a reliable genetic test for EJSCA is now available through the Veterinary Genetics Laboratory (VGL).
At Valley Equine, we are dedicated to offering the highest level of support for responsible breeding. Always look at our stallion’s genetic testing and compare it to your stock’s genetic testing before making a breeding decision or purchasing a contract.
Take Action Now to Prevent EJSCA
EJSCA is a recent and important discovery in equine genetic research. While the condition is currently untreatable, it is preventable through genetic testing and careful breeding strategies.
If you are a breeder and want to learn more about how to manage EJSCA and all genetic diseases in regards to your breeding decisions, contact Valley Equine today. Our team of experts is here to support you with the latest genetic testing and breeding guidance
