Sarcoid Development May Have Genetic Basis

The development of sarcoids--the most frequent of equine skin tumors--appears to have a genetic basis, and Swiss researchers are now honing in on the exact genes responsible for the disease.

equine sarcoid

Sarcoids located on the horse's front legs(above) and his head (below).
equine sarcoid

A new major study involving 222 horses yielded three chromosomal regions of the equine genome that could be further investigated for candidate genes responsible for sarcoids, according to Vendula Jakesova, DVM, and Vince Gerber PhD, DVM, resident and professor, respectively, in the University Equine Clinic of Bern.

"We know that bovine papilloma virus (BPV) is an important causative factor of this disease, but the sarcoid-like lesions induced by experimental BPV infection disappear spontaneously, indicating further intrinsic and/or extrinsic factors," said Jakesova during the presentation of her results at the Swiss Equine Research day held April 30 in Avenches. "We've always suspected that there was a genetic component, too. Now we're closer than ever to finding the chromosomal regions that are associated with the sarcoid trait."

Jakesova and Gerber hypothesized that the development of these unsightly tumors is a quantitative trait, meaning it occurs as a result of a variety of genetic and environmental factors. To find the genetic basis, the team (Equine Clinic of Bern, Institute of Genetics in Bern, and Animal Health Trust in Newmarket, England) studied two families of horses, descendants from two different sires. Within this study group, 8.6% of one family and 16% of the other had sarcoids.

A genome-wide search was carried out on these horses, using 315 microsatellite markers, and compared to each other. The results were analyzed using Quantitative Trait Locus Analysis (QTLA), a statistical method that calculates the probability that a certain chromosome region could be associated with the trait. The research team revealed significant sarcoid signals on several chromosomes. Only the signals that were clearly positive were further investigated. They were observed primarily on chromosome 9, as well as on chromosomes 5 and 20.

"The identification of sarcoid-related genes is one step to a better understanding of the etiology of the disease," Jakesova said. "And our hope is that this will then lead to the development of new therapies and preventive measures."

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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