UC Davis Reaffirms Original Etalon WFFS Publication
Updated: Feb 11
It's confirmed! A study published by University of California, Davis' Veterinary Genetics Laboratory confirms Etalon's discovery that "Warmblood" Fragile Foal Syndrome occurs across horse breeds. Team Etalon's publication, published in November 2020, announced that the disease is not specific to Warmbloods as was initially assumed.
Fragile Foal Syndrome (FFS), originally termed Warmblood Fragile Foal Syndrome, is an autosomal recessive lethal genetic disorder. Genetic testing for FFS has been commercially available since 2013, and was assumed to only affect Warmblood breeds. To debunk the mystery, the DNA of 7,362 horses submitted for commercial genetic testing was genotyped for FFS by Etalon researchers using hair, tissue, semen or blood samples with owner consent. The population of horses was thinned of related horses within one generation, yielding 7,343 horses representing 78 breeds or types of horse. Using this unbiased testing approach, Team Etalon observed FFS in a wide group of horse breeds. Among the sampled population of 7,343 horses of various breeds, the overall FSS frequency was 0.56%. The FFS frequency in Warmblood type breeds was 5.32 and 0.45% in other breeds.
Not long after Team Etalon's publication, "Fragile Foal Syndrome Occurs Across Horse Breeds" was released, researchers at UC Davis published the results of a similar study, also identifying FFS across numerous breeds. The study, titled "Distribution of the Warmblood Fragile Foal Syndrome Type 1 Mutation in Different Horse Breeds from Europe and the United States", screened 4081 horses belonging to 38 different breeds. In total, 4.9% of the horses representing 21 breeds carried the WFFS allele. The affected breeds were mainly warmbloods, with carrier frequency as high as 17% in the Hanoverian and Danish Warmblood. The WFFS allele was not detected in most non-warmblood breeds; however, exceptions included WFFS carriers in the Thoroughbred (17/716), Haflinger (2/48), American Sport Pony (1/12), and Knabstrupper (3/46).
Team Etalon believes that awareness that Fragile Foal Syndrome is not specific to one breed, and the utilization of comprehensive unbiased genetic testing approaches will aid in the education of breeders and registries for all breeds. We are happy to hear that UC Davis' results align with ours, and that the additional publication confirming the discovery will bring about a deeper understanding of the disease and the importance of testing. This knowledge will further reduce the variant frequency in populations, resulting in happier and healthier horses and their people!
Read more about Etalon's initial discovery and publication on our blog.