Lavender Foal Syndrome Test Offered by Cornell University

This year has been an exciting one for Arabian horse owners. Not only has the genetic mutation for lavender foal syndrome (LFS) been determined, a test that can identify affected foals and horses that carry the gene for the disease has been developed.

Lavender foal syndrome is a heritable and fatal neurologic disease that is primarily found in Egyptian Arabians. Affected foals have a characteristic soft lavender, pale pink, or silvery coat color.

Even though LFS is not particularly common, it is important because carriers appear normal, and 100% of affected foals either die or are euthanized shortly after birth.

Based on research performed by Samantha Brooks, PhD, an assistant professor in the Department of Animal Science at Cornell University, and colleagues, a mutation in a particular region of the gene called myosin Va (MYO5A) is responsible for LFS.

"Approximately 10% of the Egyptian Arabian population carries the mutation," explained Brooks. "If two carriers are bred, there is a chance the foal will have LFS. This condition is passed on via a recessive inheritance pattern, which means that there is a 25% chance that a foal will have LFS if two carriers are bred."

The LFS syndrome test identifies the mutant gene in DNA extracted from either hair roots or whole blood.

According to Brooks, the first step of the test uses a technique called polymerase chain reaction (PCR) to amplify the affected region of the MYO5A gene, where the mutation is. The second step detects the mutation (if present) in the amplified genetic material using a special protein called a restriction enzyme.

"As long as enough DNA is supplied, the test is very sensitive and completely specific," said Brooks, which means few false positive or negative test results should occur.

Brooks added, "Since all identified Lavender foals have had this same mutation, this test particularly benefits breeders seeking to eliminate the possibility of producing a lavender foal, but is also useful to those seeking to buy or sell an Arabian horse for potential breeding use."

The LFS test is offered through Cornell University's Animal Health Diagnostic Center and costs $47.00 USD. According to the Diagnostic Center customers residing outside of the United States might require a permit to send a blood sample, and blood samples are not accepted from all countries. No permit is required for hair root samples.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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