Degenerative Mielopathy : A genetic paralysis prevented thanks to a DNA test

Degenerative Mielopathy leads to a paralysis of rear paws from 8 years old. A reliable DNA test can screen stud dogs and brood bitches, in order to adapt matings and avoid birth of affected puppies and spread of the disease in the breed.


A serious inherited disease

Degenerative mielopathy is a degeneration of the spinal cord which leads, between 8 to 14 years, to a loss of coordination an to a progressive paralysis of the hindlimbs.

The first symptoms result in an oscillating gait and limb weakness. The dog dragging its paws has difficulty standing and moving. The dog becomes paraplegic and eventually develops paralysis of forelimbs. This disease can be confused with a herniated disc or a hip dysplasia.

The breeder must protect its kennel

Many dog breeds are affected by this disease : Altdeutsche Schaferhunde, Bernese Mountain dog , Boxer, Chesapeake Bay Retriever, Collie (Rough), Collie (Smooth), Czechoslovakian Wolfdog, German Shepherd, Hovawart, Kerry Blue Terrier, Poodle, Pug, Pyrenean Mountain dog, Rhodesian Ridgeback, Saarlooswolfhond, Shetland Sheepdog, Welsh Corgi Cardigan, Welsh Corgi Pembroke, White swiss Shepherd, Wheaten Terrier (soft coat) 

A stud dog « carrier » of the mutation will not develop the disease (recessive disease) but transmits it to 50% of its puppies. A stallion « carrier » of the mutation which is used a lot for reproduction, spreads the disease through the breed and helps to increase the frequency of the mutation and multiply the number of affected dogs.

As Degenerative Myelopathy is expressed at a late stage, any breeder can mate unknowgly an affected dog and transmit the mutation to 100% of its progeny.

It is recommended to perform on the main stud dogs , the DNA test for Degenerative Mielopathy (DM test) to screen this disease with a reliability above 99%.

A DNA test easy to perform

Thanks to a simple cheek swab sample, the breeder performs a DNA test (DM test) to determinate if the tested dog is clear (Normal Homozygous), carrier (heterozygous) or affected (Mutated Homozygous) for Degenerative Mielopathy.

If the tested male is carrier, the breeder will have to be carefull to mate the male with a clear female to make sure to avoid the birth of affected puppies.

In addition, the result, displayed on a genetic certificate valid through the whole life of the animal, allows to provide guarantees for a mating or to justify the sale of a puppy free from Degenerative Mielopathy.

The veterinarian who notices ataxia or paralysis issues in an old dog can perform the DM DNA test to confirm or refute the Degenerative Mielopathy diagnosis. If the dog is affected, its puppies are at least carriers and a particular attention should be paid to its lineage which probably has a greater proportion of carrier dogs.

A breeder who knows the genetic status of the dog takes no risk, secures its kennel and can then select its breeding dogs, adapt matings, avoid the birth of affected puppies and limit the spread of this serious disease in the breed.

Dr Guillaume QUENEY