High Frequencies of TNC and COL5A1 Genotypes Associated With Low Risk for Superficial Digital Flexor Tendinopathy in Greek Indigenous Horse Breeds Compared With Warmblood Horses.

Tendinopathies constitute a very common category of musculoskeletal disorders, causing economic losses in the equine industry and animal welfare issues in horse populations. Sport and racehorses are in general sensitive to tendinopathies, whereas local indigenous horse populations are often more tolerant to various disorders. Particularly, indigenous Greek horse breeds have evolved and adapted in the rough topographic features of mountainous and semimountainous Greek terrain and are less prone to develop tendinopathies. Susceptibility to tendinopathy has been proposed to be associated with three specific variants in the tenascin-C and collagen type 5 α-1 genes. The present study was designed to analyze these genes and estimate the frequency of the aforementioned variants in three indigenous Greek horse populations, namely the pinia (peneia) breed, the Messara breed, and the nondescript Macedonian pacer, in comparison with a population of warmbloods. Results revealed high frequencies of genotypes with high risk for tendinopathy in the warmblood population and high frequency of low risk genotypes in the Greek breeds. Apart from the three variants, two novel polymorphisms were detected, one of which may also be associated with risk for tendinopathy. Our findings (a) are in agreement with previous ones demonstrating that risk for tendinopathies is associated with particular gene variants and also (b) highlight the value of Greek indigenous horse breeds as a genetic resource that (c) may be used in selective breeding schemes for decreasing the risk for tendinopathies in genetically improved breeds.