Genes Identified for Osteochondrosis

An international collaboration of researchers from Europe and Australia joined together to identify genes associated with clinical manifestations of osteochondrosis (OCD), a condition  attributable to abnormal cartilage development, in Belgian warmbloods. Blood samples and X-rays were obtained from 407 horses and genome-wide association analyses were used to examine the entire genome of each animal comparing those found to have OCD in the fetlock, hock or stifle joints with those unaffected by the disease. Fourteen X-rays of the fetlocks, hocks and stifles were used to detect cartilage lesions in each horse and the location of their OCD lesions, if present, were recorded.

Almost 400,000 segments of DNA (called single nucleotide polymorphisms or SNPs) from 395 horses were analyzed. None of the SNPs or neighboring areas of the genome were related to osteochondrosis of the fetlock or hock, specifically. However, four SNPs on three Belgian warmblood chromosomes were significantly associated with osteochondrosis in general. Some of these are in areas known to be related to cartilage development at the cellular level. While the researchers are quick to point out other factors including nutrition, biomechanics and endocrinology are also involved in the development of osteochondrosis, these results suggest specific genes can be identified that are also associated with the development of this disease. 

The authors suggest that more work is needed to understand how these genes influence the occurrence of osteochondrosis and how this may vary between breeds.  

    — Drabbe A et al. JEVS 2022;103870 

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