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Presence of the glycogen synthase 1 (GYS1) mutation causing type 1 polysaccharide storage myopathy in continental European draught horse breeds
  1. J. D. Baird, BVSc, PhD1,
  2. S. J. Valberg, DVM, PhD, DACVIM2,
  3. S. M. Anderson, BS3,
  4. M. E. McCue, DVM, MS, PhD, DACVIM2 and
  5. J. R. Mickelson, PhD3
  1. Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
  2. Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St Paul, MN 55108, USA
  3. Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, MN 55108, USA
  1. E-mail for correspondence jbaird{at}

The purpose of this study was to determine which continental European draught horse breeds harbour a mutation in the glycogen synthase 1 gene (GYS1) that is known to be responsible for type 1 polysaccharide storage myopathy in quarter horses and North American draught horses. Of a non-random selection of continental European draught horses belonging to 13 breeds, 62 per cent (250 of 403) tested were found to carry the mutant allele. The horses were located in Belgium, France, Germany, the Netherlands, Spain and Sweden. The mutation was identified in animals from each of the breeds examined. In the breeds in which more than 15 animals were available for testing, the highest percentages of GYS1-positive horses were found in the Belgian trekpaard (92 per cent; 35 of 38 horses tested), Comtois (80 per cent; 70 of 88), Netherlands trekpaard (74 per cent; 17 of 23), Rheinisch-Deutsches kaltblut (68 per cent; 30 of 44) and Breton (64 per cent; 32 of 51).

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  • Conflict of interest SJV, JRM and MEM own the licence for PSSM testing and receive sales income from its use. Their financial and business interests have been reviewed and managed by the University of Minnesota in accordance with its conflict of interest policies.

  • Provenance not commissioned; externally peer reviewed

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