Immune mediated myositis/myosin heavy-chain myopathy (IMM/MYHM)
Summary
The name of this test has been updated from IMM to IMM/MYHM. This gene is now associated with both IMM and tying up that is not associated with exercise (MYHM).
This test is a new addition to the recommended tests for horses that would usually use the QH 5-panel. This includes Quarter Horses, Paints, Appaloosas, Quarter Ponies and any other breeds with some Quarter Horse bloodlines.
The primary sign of IMM is fast and severe muscle loss along the top line. It usually occurs 3-4 weeks after a strangles infection or after vaccinations. The horse will be sick: stiff, depressed, feverish and not eating.
The primary sign of MYHM is tying up not associated with exercise. Some affected horses may have muscle atrophy.
Horses with two copies of this gene are more likely to have an episode - or multiple episodes - than horses with one copy of the gene.
Gene or region and technical reference
Gene: MYH1 (marker). Reference: Finno et al. (2018)
Reported alleles
n. Test developed using manufactured DNA, animal controls.
My. Test developed using manufactured DNA.
Panels: groups of tests that are often ordered together
This test is in the QH health panel.
This test is in the QH health & colour panel.
