Gene for PSSM type 1 in European draught breeds

PSSM is a metabolic disease that results in the accumulation of glycogen and abnormal polysaccharide in muscle.

A genetic mutation of the glycogen synthase1 gene (GYS1) has been identified as the cause of some cases of PSSM in quarter horses and North American draft breeds. This form of the disease has been classified as type 1 PSSM.

A recent study has now also found the GSY-1 mutation in continental European draught breeds.

With the cooperation of the breed societies, Dr John Baird and colleagues sampled Ardenner, Belgian Draft, Breton horse, Comtois, Trait du Nord, Hispano-Breton, Netherlands Draught horse, and German cold bloods.

Overall 62% of continental European draft horses possessed the GYS-1 mutation. The mutation was present in all breeds sampled and in all six countries (Belgium, France, Spain, Germany, Sweden and the Netherlands.)

Of the breeds in which more than 15 animals were tested, the Belgian trekpard had the highest number of horses with at least one copy of the GSY1 gene (92.1%). Over a third of the Belgian trekpard tested were homozygous for the GSY1 allele - that is they carried two copies of the defective gene. The mutation was also present in over 50% of the animals tested from the Comtois (79.8%), Netherlands trekpard (73.9%), Rheinisch-Deutsches kaltblut (68%) and Breton (64.4%) breeds.

"What is striking from the present study" say the authors" is that a high percentage of horses derived from continental European draught breeds, in fact, often the majority of horses tested in each breed, were positive for the GYS-1 mutation."

However they stress that, as the research was not based on random samples, it cannot be relied on to give an accurate assessment of the prevalence of the GSY-1 mutation in continental European breeds.

For more details see: http://www.equinescienceupdate.com/articles/gpedb.html