I’m a person that wants to work with my vet. I know of the hair pull/genetic ‘testing’ you can get done. I’m hoping to find there is more growth in establishing new testing to identify and treat such concerns…that vets do endorse and that are acknowledged. 
Has that testing grown further to be accepted as legit in the vetting community yet?
Type 1 testing is and has been valid for a good while.
It’s hair testing for Type 2 and the variants which have been under question since the start, though a lot of people have made dietary changes based on those tests with good results. The U of Minnesota is now involved and doing a lot of research on Type 2/variants. Those really need to not be called PSSM because it’s not, but maybe the newer and more substantiated testing will bring about a new name.
That said, there are still a lot of vets who don’t think PSSM is an issue, but that’s their problem, as PSSM1 is 100% legit. PSSM2 is as well when seen via muscle biopsy but that’s such an invasive procedure not a lot of people choose to do it.
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yes, we did test for Type 1, since it was a legit test. done with vet. But Mare still exhibiting symptoms that may point to type 2 variants, but I was only hoping the vet community had gotten closer to recognizing/validating the ‘other variants’, and the establishment of hair pulling being a valid way to estabish it. but sounds like still not yet. Biopsy not only invasive? but will it show the variant? the treatment? the feed recommended? I dunno.
People get pretty hung up about the biopsy being invasive but it really isn’t that big of a deal and cost was in the same ballpark as the test equiseq is selling.
The biopsy can’t tell you what variants…because they haven’t been scientifically validated. There also have been no trials on feeding strategies for these variants either.
What the muscle biopsy can do is identify specific muscle abnormalities and MSU is starting to parse out abnormalities beyond PSSM1 based on staining techniques like RER and MFM and there are dietary adjustments recommended for those disorders.
Equiseq has been saying for YEARS that they are just about to publish and here they are still selling their test with no validation.
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thanks, knic. Its all the same then…I so wanted a ‘time’ when validation would be given ‘or not’… I wouldn’t ‘mind’ the biopsy if I felt it gave more exact information. I’ve heard, too? results may vary and if muscles aren’t stressed as much as scale, etc…not always definitive unless HIGHLY readable. so, I dunno.
I’ve been aware of equiseq for at least 5 years and it’s been the same story the whole time.
The portal is down so I can’t open them but Valberg published two studies last year that tested the commercial variants against horses diagnosed by muscle biopsy with MFM and the commercial tests didn’t correspond to the horses muscle biopsy.
If you have exhausted other diagnostics and the horse is actively showing symptoms it would probably be worthwhile to do the biopsy. My horse had a biopsy and didn’t end up having a muscle myopathy but the other abnormalities they did find on the muscle biopsy lead to diagnosing his issue. So I found the biopsy very worthwhile.
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Thank you for mentioning this - do you have a link to where these Valberg studies can be found? This has been my concern all along with the tests Equiseq offers and it is frustrating when I hear breed organizations pushing for this testing to be used to determine which horses should and shouldn’t be bred. They’ve promised publication for years, yet none seem forthcoming…probably for this exact reason - the tests they offer for PSSM2 are not sufficiently reliable as a diagnostic to meet publication standards. Yet people buy the test anyway, so maybe there isn’t much incentive to publish or do more research from their perspective.
Lots of useful info on the MSU website:
And the links to the research pubs:
https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.13286
https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.13345
It’s a shame that reputable labs have had to divert resources towards looking at these commercial tests. Which breed associations are implementing the equiseq tests? That is scary.
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Thank you so much for the links. I’m not sure exactly which breed organizations are considering implementing PSSM2 testing requirements. I am involved in a small breed association and it has come up for us and there is apparently “social media pressure” for warmblood associations in general to do this. It is deeply disturbing to me (genetics, DNA analysis, and interpretation of genetic testing results is my field of expertise) but I am in the minority arguing against it.
PSSM1 testing is robust and I fully support relevant registries requiring it, but PSSM2 “testing” just isn’t. Unfortunately, too many people use the term “PSSM” generically and don’t realize there are significant differences between PSSM1 and what is currently being labelled as PSSM2. It’s super frustrating - words matter! Ok…rant over… 
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You could just start treating him like some type 2 variant. Lower NSC feeds, higher protein and higher quality protein. LOTS of people are finding very good results adding whey isolate.
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I did both the type 1 and type 2 test when my gelding began having significant muscle wasting, muscle tremors, increased issues with cantering, back and lumbar pain when grooming, lethargy, abscesses in his feet…honestly the list goes on. I had bloodwork done and he did have elevated enzymes related to muscle damage (AST, CK, etc). My vet automatically assumed PSSM but since he is a Standardbred, he was not convinced it was type 1.
I did the hair pull for type 1 and it came back negative. At this point in time I had started following the 3 Facebook groups associated with PSSM type 1 and 2 and began to make dietary changes. I saw some change with just the addition of SmartPak’s Smart Muscle Recovery and DMG. I saw no difference with the change to a low NSC feed.
I then did the hair test for type 2 through Equiseq. I didnt want to do a muscle biopsy because I too thought it was too invasive. My vet said he would need to go to a clinic for it and then be on stall rest after. I felt after watching him waste away, I didnt want to put his body through more stress, plus he generally tied up on trailer rides. I sent the hair off and he has the mutation present for P2. I do not like that these tests are not validated. I took the results with a grain of salt but went ahead with even more diet changes as recommended by the PSSM type 2 community on Facebook.
He is now on a very high protein feed (soy bean hulls), Coolstance copra, Cocosoya oil, a magnesium supplement, salt pellets, multi-vitamin, high point alfalfa to balance calcium to phosphorus ration along with monosodium phosphate, and a large addition of bio-available vitamin e. He has improved dramatically in a year’s time. While I do not fully trust the results from Equiseq, I trust that the diet change made all the difference for him which kind of validates the results slightly in my mind.
I think the owner of Equiseq is a little too validated by the Facebook groups. He is always suggesting people who dont know what to do with their horses and are at their wits end with testing and veterinary diagnostics, to run his test. It just seems odd that it has been so long and he hasn’t published anything. I agree that I think the fact that people do buy the test (myself included) makes it so he has little reason to go through the lengthy and difficult peer review process.
Trusting the bloodwork results, the outward symptoms I saw, and the complete 180 my gelding made on the new diet, I believe he has some type of muscle issue. Whether he is really PSSM Type 2 or something else is still a mystery to me.
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Way back when I started my PSSM journey (it was still called EPSM! 
) the muscle biopsy was the only diagnostic method and the only thing you could do was change the horse’s diet and management. The biopsy apparently required a significant chunk of muscle back then. As the recommended diet was considered safe for non PSSM horses some people opted to just try the diet and management and see if anything changed given 4-6 months.
Is there any reason not to do that anymore?
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There’s no reason someone can’t try either diet and see if either helps.
PSSM1 is easy to test via hair, so I’d do that first. If that’s negative, assume Type 2 and work on that diet
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I would totally just opt to change the diet over diagnostics if you really suspect PSSM
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Not that I ‘suspect’ it per se, but we cannot find anything (we did find ulcers and are treating and checking improvement) to ‘explain’ her falls (at a walk…) her balking at forward, her bucking and popping up a few times, her cross firing, her ‘intensity’ in being looky, etc, etc. we’ve done full body/bone scan and most diagnostics we could, and she gets chiro regularly, (and has been reactive and tight/sore in certain muscle areas) and her diet is ‘basically’ already adapted … but if PSSM 1 or PSSM 2 /different variants supposedly can be aided by different supplements.
I gotta say that my young horse had literally all these symptoms just from ulcers…and it’s taken 3 full weeks of gastrogard and sucralfate to see any significant, consistent improvement. So I guess I’d wait until the ulcers were fully resolved before looking for other causes…
thanks, leheath!!! yes, she’s on her second course of attack, after her second scope and ulcers still obvious. so we are continually working with that. didn’t (to me) explain the falling at a walk, and other strange travelling lameness, but that was our only totally identifed/able to treat concern so we’re on it! 
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