Degenerativ Myelopathy

  • Information
  • DNA-test

Degenerative Myelopathy (DM) is a deteriorating neurological disorder with an immunological background. It occurs when a dog's own immune system attacks its central nervous system so that the isolating layer myelin around the nerve fibers in the spinal cord is broken down.  DM is often occurs in middle-aged dogs off larger breeds.  German Shepherd is often affected and even if you consider the high number of registered dogs of that breed the frequency is high.


The weakness in the hindquarter comes insidious and is shown by staggering and wobbling movements in the back legs that gradually aggravate. Movements become unsecure and fumbling, feeling and reflexes deteriorate and a typical sign is that the dog drags its back paws witch result in nail scraping and worn down nails. The reflex in the kneecap is often totally gone in affected dogs but in individual cases it might become heavily exaggerated instead. In fast movement straight forward may the symptoms be insignificant but in a slow pace the lack of mobility becomes evident. One typical symptom is that when the dog is turning the back legs crosses or gets tangled up. In the late stage the tail is affected and tends to just hang down. The muscles atrophies can no longer get up. Incontinence is also a part of the last stage. The disease in not painful and there is no treatment. The symptoms are caused by degeneration of the nerves that goes to the back legs and hindquarter.


The Orthopedic Foundation For Animals has a DNA test that can be purchased to see if their dog carries the mutated genes for DM. The test is for any dog but is only recommended for certain breeds. The test consists of a cheek swab (using something similar to a Q-tip to swab the inside of the cheek to submit for testing)


The test checks for the mutated gene that will tell if your dog may be affected by degenerative myelopathy, if it is a carrier, or if it is unaffected.


The results are: (In some cases the letter A is exchanged with DM and then the result would look like this; N/N=clear, N/DM=carrier, DM/DM=affected)


  • Normal/Normal /N/N) - this means your dog does not have the mutated strain and it will not develop degenerative myelopathy. (clear)

  • Normal/Abnormal (N/A) - this means your dog is a carrier of the gene but will not develop degenerative myelopathy. (carrier)

  • Abnormal/Abnormal (A/A) - this means that your dog is affected with degenerative myelopathy and may develop DM. (affected). Not all dogs with A/A results will develop DM.


Breeding risks for degenerative myelopathy can be calculated using the Punnett Square:


  • If both parents are clear (N/N then all of the puppies will be clear.

  • If one parent is a carrier (N/A) and one is clear (N/N) then roughly 50% of the puppies will be clear and 50% will be carriers.

  • If both parents are carrier (N/A) the roughly 25% will be clear (N/N), 50% will be carriers (N/A) and 25% will be affected (A/A).

  • If one parent is clear (N/N) and one is affected (A/A) then all the puppies will be carriers (N/A).

  • If one parent is a carrier (N/A) and one is affected (A/A) then roughly 50% of the puppies will be carriers (N/A) and 50% will be affected (A/A).

  • If both parents are affected (A/A) then all the puppies will be affected (A/A).

The DNA-test for  Degenerativ Myelopathy can be sent to the following laboratories.


Van haeringen group (also provide for the dwarfism test)

The cost of the analysis is 59,50€


LABOKLIN(also provide for the dwarfism test)

Go to: "genetics" -- "genetic diseases"-- "dogs" -- "degenerative myelopathy"


 

Tests without central registration - Important information from SKK

The above test does not have central registration in SKK but it is important to remember that you are always obligated to take consideration to the test result, even if it didn’t came out the way you expected.


Instructions

If you want to test your dog with a genetic test that does not have central registration you should use SSK’s general referral “Remiss DNA-test”. This referral is used to secure the dogs identification when blood sample is taken. The referral is absolutely necessary for a possible future registration of your dog’s results. If the DNA-test you wish to perform can be registered in the future, with the help of the referral you can register your dog’s result afterwards. If you are missing the SKK referral your dog’s result will not be accepted for central registration. On the referral you have to state what disease the test is for, what laboratory that perform the test, which veterinary that does the sampling, owner of the dog and all information about the dog. Your veterinary take the blood test and the blood test is sent by the veterinary to the laboratory. The referral together with a copy of the test result is sent to SKK. Sent in referrals will be saved at SKK without measure until decision about central registration possibly is taken. The dog owner is also encouraged to send a copy of the test result to the breed club.


Referral DNA-test (pdf file)