Mammalian Genome

, Volume 23, Issue 3, pp 294-303

First online:

A genome-wide association study of osteochondritis dissecans in the Thoroughbred

  • Laura J. CorbinAffiliated withThe Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh Email author 
  • , Sarah C. BlottAffiliated withAnimal Health Trust
  • , June E. SwinburneAffiliated withAnimal Health Trust
  • , Charlene SibbonsAffiliated withAnimal Health Trust
  • , Laura Y. Fox-ClipshamAffiliated withAnimal Health Trust
  • , Maud HelwegenAffiliated withAnimal Health Trust
  • , Tim D. H. ParkinAffiliated withBoyd Orr Centre for Population and Ecosystem Health, Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow
  • , J. Richard NewtonAffiliated withAnimal Health Trust
  • , Lawrence R. BramlageAffiliated withRood and Riddle Equine Hospital
    • , C. Wayne McIlwraithAffiliated withCollege of Veterinary Medicine and Biomedical Sciences, Colorado State University
    • , Stephen C. BishopAffiliated withThe Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh
    • , John A. WoolliamsAffiliated withThe Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh
    • , Mark VaudinAffiliated withAnimal Health Trust

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Osteochondrosis is a developmental orthopaedic disease that occurs in horses, other livestock species, companion animal species, and humans. The principal aim of this study was to identify quantitative trait loci (QTL) associated with osteochondritis dissecans (OCD) in the Thoroughbred using a genome-wide association study. A secondary objective was to test the effect of previously identified QTL in the current population. Over 300 horses, classified as cases or controls according to clinical findings, were genotyped for the Illumina Equine SNP50 BeadChip. An animal model was first implemented in order to adjust each horse’s phenotypic status for average relatedness among horses and other potentially confounding factors which were present in the data. The genome-wide association test was then conducted on the residuals from the animal model. A single SNP on chromosome 3 was found to be associated with OCD at a genome-wide level of significance, as determined by permutation. According to the current sequence annotation, the SNP is located in an intergenic region of the genome. The effects of 24 SNPs, representing QTL previously identified in a sample of Hanoverian Warmblood horses, were tested directly in the animal model. When fitted alongside the significant SNP on ECA3, two of these SNPs were found to be associated with OCD. Confirmation of the putative QTL identified on ECA3 requires validation in an independent sample. The results of this study suggest that a significant challenge faced by equine researchers is the generation of sufficiently large data sets to effectively study complex diseases such as osteochondrosis.