Not only is polysaccharide storage myopathy (PSSM) a common and important muscular disorder in various horse breeds in the United States, but according to a recent research report, it is also a common diagnosis in horses in the United Kingdom.

In the study, “Prevalence of equine polysaccharide storage myopathy and other myopathies in two equine populations in the United Kingdom,” Catherine McGowan, BVSc, DipVetClinStud, MACVSc, DEIM, PhD, and colleagues analyzed muscle biopsy samples collected from 94 horses from an abattoir and 46 horses presented with a neuromuscular disorder to The Royal Veterinary College in Hertfordshire, UK, to determine the prevalence of PSSM in the UK.

Muscle biopsy of a horse with PSSM, showing an accumulation of abnormal polysaccharide (purple stains).

According to the researchers, PSSM is a common and important diagnosis that occurs in typical breeds of horses including drafts, Warmbloods, and related breeds.

“This is also the first study to diagnose PSSM in cob-type horses,” said McGowan.

Future research focusing on genetic testing is ongoing.

“In the meantime, muscle biopsy examination should be performed in suspected cases since obtaining a definitive diagnosis of PSSM is important for selecting appropriate treatment, predicting outcome, and determining whether a horse is suitable for breeding or not,” summarized McGowan.

The article is scheduled to be published in the June 2009 edition of The Veterinary Journal. The abstract is currently available on PubMed.