Polysaccharide storage myopathy type 1 (PSSM1)

Why test for PSSM1?

Polysaccharide storage myopathy is a muscle disease that can cause "tying up" symptoms: muscle weakness, shivers, work intolerance, and even muscle wasting particularly in the hindquarters.

Unlike the other inherited disorders that we test for, PSSM1 is not recessive. This means that horses which inherit the PSSM1 mutation from just one parent can show signs of this disorder. To complicate matters, not all horses with the PSSM1 mutation show signs of this disease - its effects range all the way from negligible to fatal. Not all cases of tying up are caused by PSSM1 either: one study found that only 65% of a group of horses with moderate to severe signs carried this particular mutation.

Testing for PSSM1 is valuable for both breeders and riders in eliminating or confirming a major known cause of tying up. Speak to your veterinarian about the management of PSSM1 horses.

PSSM1 in various breeds

PSSM1 has been found in:

  • Quarter Horses
  • Paint Horses
  • Appaloosas
  • Gypsy Cobs
  • Belgian Drafts
  • Thoroughbreds
  • Warmbloods
  • Polo ponies
  • Connemara cross
  • Belgian Draft Horses

It may also occur in other breeds and crosses.

Purchase equine DNA testing

Price per horse = sample processing ($40) + tests

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Inherited disorders

Pure and part-bred Arabian

$14 Cerebellar abiotrophy (CA) ...read more
$14 Severe combined immune deficiency (SCID) ...read more
$14 Lavender foal syndrome (LFS) ...read more

Fell Ponies, Dale Ponies and Gypsy horses

$14 Foal immunodeficiency syndrome (FIS) ...read more

Pure and part-bred Friesian

$19 Friesian dwarfism ...read more
$14 Hydrocephalus (Friesian and other breeds) ...read more

Warmbloods and related breeds

$14 Fragile foal syndrome (FFS) ...read more

Various breeds

$14 Polysaccharide storage myopathy type 1 (PSSM1) ...read more

Quarter horses and related breeds

$14 Malignant hyperthermia (MH) ...read more
$14 Hyperkalemic periodic paralysis (HYPP) ...read more
$14 Hereditary equine regional dermal asthenia (HERDA) ...read more
$14 Glycogen branching enzyme deficiency (GBED) ...read more

Saddlebred horses and related breeds

$14 Junctional epidermolysis bullosa, Saddlebred form (JEB) ...read more

Pure and part-bred Akhal Teke

$14 Naked foal syndrome (NFS) ...read more

Pure and part-bred Connemara

$14 Hoof wall separation disease (HWSD) ...read more

Coat colour tests

Base coat colours

$9 Agouti (the bay factor) ...read more
$9 Extension (red/black) ...read more

Coat colour dilutions

$9 Cream ...read more
$9 Dun and d1 ...read more
$9 Silver ...read more
$9 Champagne ...read more
$9 Pearl ...read more

Coat patterns

$9 Grey ...read more
$9 Appaloosa or leopard (CSNB) ...read more
$9 PATN1 ...read more
$9 SW1 (Splashed White 1) ...read more
$9 SW2 (Splashed White 2) ...read more
$9 SW3 (Splashed White 3) ...read more
$9 Frame overo (OLWS) ...read more
$9 Tobiano ...read more
$9 Sabino 1 ...read more
$9 W13 dominant white (Miniatures) ...read more
$9 W20 white markings ...read more
$9 W22 dominant white (TB, Paint) ...read more
$9 W25 dominant white (TB) ...read more
$9 W26 dominant white (TB) ...read more
$9 W27 dominant white (TB, Paint) ...read more
$9 Roan marker ...read more

Parentage/DNA profile

$33 DNA profile (microsatellite) ...read more

Remember: most breed societies ask members to test through their society.

Parentage verification: