Horses that test negative for PSSM 1 but have strong PSSM symptoms are tested for PSSM 2. Previously the only way to test for PSSM2 wass with an invasive muscle biopsy, and many still choose to have this test done.  


The equine genetic world is advancing rapidly and there is a company pursuing testing for PSSM2 - to date they have found 4 variants for PSSM2.  A hair test is now publicly available (in the USA) to test for the P2, P3, P4 and P5 and they are working on another variant at the time of this writing.  They have also developed a test for what is being labeled as PX. 

Please contact for more info on testing. 

If you are outside the USA you can order a test from Equiseq and they will send you a card to send back to them with a dried blood sample.  The tests are fairly costly at this point as all new genetic testing is at first but the compnay is very easy to work with and has your horse's best interest at heart.  Many breeders are still not testing for PSSM2 and most testing is being done because a horse is showing symptoms and the owner is looking for answers.   In the future as costs come done breeders will routinely test for all of the tests. 


The symptoms for PSSM 2 are very similar to PSSM 1 and are often more severe.  We recommend testing first for PSSM 1 and then if that comes back negative, pursue a PSSM2 diagnosis.

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Our main goal is to find the source horses for genetic diseases. In the meantime we also provide information to help Breeders, Buyers and Owners make good choices when breeding buying or selling their horses.

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