Our genetic test
Six variants can now be tested that are associated with the development of PSSM2 symptoms in horses. In Europe, generatio is the only laboratory with the exclusive licence for the PSSM2 test.
The test can be done using hair roots (pulled out hairs from tail or mane) or EDTA blood (collection and shipment only possible by veterinarian).
The prices for our PSSM2 test can be seen in the store. Choose between:
- PSSM2-6 variants: for all horse breeds except Icelandic horse
- PSSM2-Icelandic horse: with these only P3, P8 and K1 have been found so far
Advantages
- By sending in mane or tail hair, the tests can also be ordered by private individuals
- No muscle biopsy with invasive procedure
- Result already after 10 to 15 working days
- Only one sample for several tests and sample storage in our archive
- Digital result delivery
- Personal support by our highly qualified personnel from the fields of laboratory technology, veterinary medicine and biology
The advantages of genetic testing for PSSM2
PSSM2 Equine Myopathy is a multifactorial hereditary muscle disease in horses. The PSSM2 test panel offered by generatio is composed of six variants identified as risk factors for developing symptoms of PSSM2. It is recognized that the equine myopathies grouped as PSSM2 are hereditary and multifactorial. This means that multiple genes and the environment interact to contribute to the development of symptoms. Like many similar human muscle diseases, the muscle disorders classically designated as PSSM2 are adult-onset, with most young horses not showing obvious symptoms before full muscle maturity, unless exposed to a great stressor which causes negative nitrogen balance.
Our position that PSSM2 tests are valid and useful is based on results of several thousand horses with a strong correlation of clinical PSSM2 manifestations and the presence of one or more of the genetic defect variants. Although there are obviously still other variants to be identified, being able to test for the current 6 variants provides owners, breeders, and veterinarians with strong tools to help diagnose, support, and plan breeding programs to minimize the production of affected animals.
Several papers have tried to discredit the PSSM2 tests by asserting that they do not correlate to biopsy findings. It is inappropriate, however, to classify animals with clinical symptoms of muscle disease as “normal” simply because they have no obvious abnormalities on biopsy. Many symptomatic horses have normal biopsies; this holds for many diseases, not only PSSM2.
Multifactorial disorders are much more difficult to study than those that are caused by a single gene mutation without environmental influences. Diseases like PSSM2 require long-term studies of large numbers of horses, including the comparison of genotypes, symptoms, and environment (feeding, stabling, training) in order to dissect the contributions of each factor to the individual phenotypes of each horse.
Due to its established usage, the equine community continues to use the term PSSM2 to clinically describe cases of Equine Myopathy in horses with symptoms of muscle disease that are similar to PSSM1, but not explained by the PSSM1 mutation (GYS1 c.926G>A). Currently, the only means to reliably detect genetic mutations that predispose a horse to developing clinical symptoms of PSSM2 Equine Myopathy is the PSSM2-6 Variant test offered by EquiSeq and generatio.
Scientific survey on PSSM2
generatio is performing research on multiple fronts and has launched an extensive scientific survey to systematically gather more data on genetic profiles, clinical symptoms, and influencing factors in tested horses. All owners who have tested horses for PSSM2 are being encouraged to complete the survey. After data analysis, a publication will be prepared which will help us to better understand the background of PSSM2 and to help affected horses even more effectively.