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MIM Muscle Integrity Myopathy Panel

Name: MIM Muscle Integrity Myopathy Panel
Brand: Generatio
Price: 357.32 EUR

Panel of 6 tests that reads six DNA markers sold as linked to muscle problems (formerly called PSSM2). Reads six...

€357.32 Incl. VAT

About

This panel reads six DNA variants that are sold commercially as markers of Muscle Integrity Myopathy (MIM), formerly called PSSM2. Their link to muscle disease has not been confirmed by independent research.

It is for owners who want to know, or need to show, which of these variants a horse carries.

Why test?

A record of the variants. The certificate documents them, if you or someone you deal with asks for this information.

A horse with muscle problems. Start with your veterinarian. PSSM1 has its own validated DNA test, and a muscle biopsy is the reference diagnosis for PSSM2.

Clinical signs

PSSM2 is the name given to horses whose muscle biopsy shows abnormal sugar storage but who do not carry the PSSM1 variant. Its causes are still unknown. Myofibrillar myopathy (MFM) is a related diagnosis, also made on biopsy.

In Warmbloods diagnosed with PSSM2 by biopsy, problems usually began around 6 years of age. More than half showed:

A decline in performance
Reluctance to collect
Reluctance to go forward

None of these signs is specific. Pain, lameness, back problems, other muscle diseases and management can all cause them.

Transmission

Each variant is passed on like any other piece of DNA: a horse with one copy gives it to about half of its foals, and a horse with two copies gives it to all of them.

There is no established pattern of inheritance for disease, so we give no mating risks for this panel.

Prevention

Breeding. Do not select horses for or against these variants.

A horse with muscle problems. Diagnosis and management belong to your veterinarian. Do not change diet or work on the strength of this panel alone. In Warmbloods with PSSM2 confirmed by biopsy, 80% of owners reported overall improvement on the recommended diet and exercise programme.

Results

The certificate lists the result for each of the six variants: P2, P3, P4, P8, Px and K1.

A variant found does not mean the horse has, or will develop, a muscle disease.

No variant found does not rule out PSSM2, MFM or any other muscle problem.

Sample

Hair roots: 20 to 40 hairs pulled (not cut) from the mane or tail, with the roots attached. Tape them inside the marked area of the printable sample submission form. Hairs without roots cannot be analysed.

Blood: 5 mL of whole blood in a K3-EDTA tube, collected by a veterinarian. Label the tube with the horse's name and send it with the submission form.

This is a DNA test. It cannot be done on a muscle biopsy sample.

Keep samples dry and at room temperature, and do not freeze them. Do not send hair that is wet, mouldy or soiled with bedding or faeces.

Send your sample by regular mail or express delivery to:

Equigerminal Lab HIESE
Rua da Quinta do Sobreiro Nº25
3230-343 Penela, Portugal

Turnaround

Standard processing: results within 5 to 10 working days of the sample arriving at the laboratory. Shipping is arranged and paid for by the client, and transit time is not included in the 5 to 10 working days.

Samples that fail DNA extraction or amplification are repeated at no extra cost, which may add a few working days. We contact you if a new sample is required.

How it works

🛒 Purchase the test: select and buy the test online.

📧 Receive instructions: after payment confirmation you receive sample collection instructions by e-mail.

✨ Collect the sample yourself: pull 20 to 40 hair roots with the bulb attached, or ask your veterinarian to collect blood in a K3-EDTA tube.

📄 Complete the form: print and complete the submission form with the animal identification.

📮 Send it to the laboratory: Equigerminal, S.A., HIESE, Rua da Quinta do Sobreiro, 25, Quinta Vale do Espinhal, 3230-343 Penela, PORTUGAL.

📄 Receive your report: your certified report is issued as soon as the analysis is validated.

FAQs

Does this panel test PSSM1 or other muscle disorders?
No. It reads only the six variants listed under Results.

For Professionals

Genetic and clinical detail for veterinarians, geneticists and laboratories.

Loci genotyped (gene, commercial variant name, inheritance). None has an OMIA entry, an ISAG/AVCG classification, a peer-reviewed discovery publication or a published HGVS description in our sources.

MYOT: P2; no established mode of inheritance; not associated with biopsy diagnosis (Valberg et al., 2021; 2023).
FLNC: P3 (research papers test two FLNC changes, P3a and P3b); no established mode of inheritance; not associated with biopsy diagnosis (Valberg et al., 2021; 2023).
MYOZ3: P4; no established mode of inheritance; not associated with biopsy diagnosis (Valberg et al., 2021; 2023).
PYROXD1: P8; no published horse study found.
CACNA2D3: Px; no published horse study found.
COL6A3: K1; no published horse study found.

Independent validation: Warmbloods (54 controls, 68 biopsy-diagnosed) and Arabians (30 controls, 30 biopsy-diagnosed): no P variant associated with diagnosis; sensitivity below one in three for every variant (Valberg et al., 2021). Quarter Horses (229 controls, 163 with PSSM2 on biopsy): P2, P3 and P4 not associated; 57% of controls and 61% of cases carried at least one of them, so using them would have labelled those controls positive and missed 40% of cases (Valberg et al., 2023). The 2021 authors concluded that these tests should not be used for selection, breeding, pre-purchase examination or diagnosis.
Distribution: P variants were also found in ancient horses 400 to 5,500 years old, and P2 in the Przewalski's horse (Valberg et al., 2021).
Nomenclature note for veterinarians: MIM (Muscle Integrity Myopathy) is a commercial panel name; we found no scientific definition of MIM as a disease.

Key references:

Valberg SJ, et al. (2021). Commercial genetic testing for type 2 polysaccharide storage myopathy and myofibrillar myopathy does not correspond to a histopathological diagnosis. Equine Vet J. doi:10.1111/evj.13345.
Valberg SJ, et al. (2023). Absence of myofibrillar myopathy in Quarter Horses with a histopathological diagnosis of type 2 polysaccharide storage myopathy and lack of association with commercial genetic tests. Equine Vet J. doi:10.1111/evj.13574.