Mutation Causing Lavender Foal Syndrome Identified

A mutation in the gene called myosin Va (MYO5A) is responsible for Lavender Foal Syndrome (LFS), reported a group of researchers from Cornell University and The Maxwell H. Gluck Equine Research Center.

LFS is a heritable, fatal, neurological disease of horses that primarily occurs in the Egyptian Arabian, a sub-group of the Arabian breed currently found worldwide. Common clinical signs in affected foals are seizures, opisthotonos (severe hyperextension of the head, neck, and spinal cord), stiff, paddling leg movements, and nystagmus (involuntary movement of the eyeballs). Perhaps most characteristic is the soft lavender color of the foals' coats.

"There is no cure for LFS, and it is difficult to diagnose because the clinical signs are similar to other neonatal conditions, such as neonatal maladjustment syndrome and encephalitis," said lead researcher Samantha A. Brooks, PhD, an assistant professor from the Department of Animal Science at Cornell University's College of Agriculture and Life Sciences.

Based on research performed in human medicine and in other animal species, Brooks and colleagues scanned the entire genome of 36 Egyptian Arabian horses using a newly available technique called a "single nucleotide polymorphism [SNP] chip." Using this genetic chip, the research team identified the MYO5A gene and discovered that a single mutation in a specific region of (exon 30) was present in all tested horses.

Further genetic testing, using a Restriction Fragment Length Polymorphism assay, found that six of six foals with LFS had two copies of the mutation (i.e., they were homozygous for the MYO5A mutation).

"We also found that 10.3% of the Egyptian Arabian horses unrelated to the foals diagnosed with LFS were carriers of the mutation," added Brooks. This means that the carrier horses had one copy of the mutant gene, not two.

"The discovery of the gene responsible for LFS is very exciting, as it can be used by breeders to test their horses and avoid carrier-to-carrier matings and thus prevent the birth of affected foals," said Brooks.

The study, "Whole-genome SNP association in the horse: Identification of a deletion in myosin Va responsible for Lavender Foal Syndrome," was published April 15. It is available for free online at

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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