Biomarker for EDM

[Libby2563]

I’m hearing and reading mixed things about the value of a blood or CSF test for EDM. Curious if anyone knows more. From what I understand it’s a bit indirect, in that it detects a marker of axonal injury/degeneration. A positive test is supposedly significant though a negative test can’t rule it out. More here: https://thehorse.com/198535/marker-tested-for-iding-neurologic-disease-in-horses/

The research team found that serum pNfH concentrations >1 ng/ml were significantly associated with an eNAD/EDM diagnosis (P=0.01). Serum pNfH concentrations were <1 ng/ml in neurologically normal, CVCM, and some eNAD/EDM and shivers horses. CSF pNfH concentrations of >3 ng/ml were significantly associated with axonal degeneration due to either eNAD/EDM or CVCM (P=0.0001) but not shivers. Values below these levels did not rule out neurologic disease.

However, this article says, “The phosphorylated neurofilament heavy-chain (PNF-H) biomarker is not reliable for diagnosis” (https://equimanagement.com/articles/aaep-2021-edm-causes-poor-performance-in-horses/). There’s no specific citation but the article is mostly quoting the very knowledgeable Dr Amy Johnson.

Does anyone know any more about this? Any personal experiences? @Xctrygirl I know you’ve been busy with the helmet studies but if you care to chime in I’d appreciate it!

[Xctrygirl]

I would stand 100% behind Dr. Johnson’s sentiments.

Em

[Critter]

I spoke directly with Dr. Finno, one of the research vets out at UC Davis who helped develop the test when I went through EDM diagnosis with my gelding. She told me that they are seeing that the test is less useful in warmbloods…and slightly more reliable in other breeds. They did not have a reason as to why. If the test comes back positive, it usually will indicate EDM. But, if it comes back negative, it does not rule out EDM.

For what it’s worth, my gelding had really bad patho results consistent with EDM (bilateral brainstem involvement) and he tested negative on the pNfH testing. He was warmblood.

I really hope they one day find a test that is conclusive and can be done before they are euthanized…it’s a horrible decision to make when you aren’t certain of the diagnosis. And a long wait for the patho results.