following on from 'PSSM your story'

[Meredith]

I read the thread "PSSM your story" and asked what it was as I had no idea.

The replies convinced me to send hair from my horse for the test as she had some symptoms.

The results came through today and I think I am relieved the horse does not have PSSM but what does the rest mean? Can anyone help please? I asked Animal Genetics and they said it was up to me to investigate the results..... Not much good when Googling it returns you to the AG website which I don't understand.

Results here....

n/n
Clear: Negative for the PSSM Type 1 gene mutation.
n/P1
Heterozygous: Horse carries one copy of the PSSM Type 1 gene mutation and is affected.
P1/P1
Homozygous: Horse has two copies of the PSSM Type 1 gene mutation and is affected.

Thanks in advance.

 

[Leo Walker]

those are just the different versions of the gene horses can have.

n/n means doesnt have it and cant pass it on
n/P1 means horse has it and has a 50/50 chance of passing it on
P1/P1 horse has it and will always pass it on

 

[Meredith]

Thanks for your reply Leo Walker.

So if a horse is clear I wonder why the other 2 options are listed with 'is affected' because I read it that my horse was clear of type 1 but had a 50% chance of passing on something and a 100% chance of passing on something else.

 

[Leo Walker]

I think its probably just like a key, so you look at your result then go to that bit to see what it means. Hard to tell without seeing it in context though!

 

[Xanthoria]

yes Leo is right - it's just a key. Somewhere on your results it should say if your horse is EITHER n/n, OR n/P1, OR P1/P1.

But what about PSSM 2, 3 or 4? Those can't be tested by hair samples - equiseq.com does blood testing for those variants but jury is out on that. A muscle biopsy can tell you about PSSM2 though. I did both hair (for PSSM1) and muscle biopsy (for P2) and the P2 came back positive. equiseq asked for blood to test the variants in a trial they did, and my guy came back with the following:

P2: n/n
P3: n/n
P4: n/P4 Potentially affected: Horse carries one copy of the P4 PSSM2 variant, and is at risk for developing PSSM2.

More here: http://equiseq.com/buy_pssm2.php

 

[Meredith]

Thank you both for the explanation.

I will read about types 2, 3 and 4.

As always with horses, learning all the time.