PSSM1 is Polysaccharide Storage Myopathy - it is a dominant disease Genetic Testing is Available
PSSM has many symptoms includung exercise intolerance, tying up, pain, stiffness, and tremors, and sweating profusely. Muscles are often damaged during episodes. Some cannot stand after an episode and death can occur. Many PSSM symptoms are confused for normal horse behavior - eg.s bucking, rolling, biting at the cinch, colic, stretching, camped out stance, Jekyll and Hyde personality.
Treatment starts with eliminating all sugar from the diet and progresses to adding other supplements, including fat. Regular exercise can help manage symptoms.
PSSM1 is seen in Quarter Horses, Paints, Appaloosas and crossbreds of these breeds, as well as Percherons, Belgian Drafts, Selle Francais, Trekpaard, Comtois, and Bretons
PSSM1 is one of the required tests in the 5 panel of tests required by all Quarter Horse breeding stallions.
Some horses that have been described as "hard to start", moody, grumpy, or "just need miles" suffer from PSSM. Symptoms include weird things like flipping in cross ties, being "cinchy, rock hard tense muscles, mysterious lameness, hard to get on a certain lead, bucking when they lope, trouble standing for the farrier, and many other strange symptoms including the major one - tying up - that many horses experience at one time or another, but the PSSM horse is plagued by them.
Genetic Testing is Available