Cerebellar Degeneration-Myositis Complex (CDMC) in the Nova Scotia Duck Tolling Retriever

Quick Summary

Cerebellar Degeneration-Myositis Complex (CDMC) is a heritable disorder that causes neurological signs that manifest as early as 10 weeks of age in affected Nova Scotia Duck Tolling Retrievers.

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Phenotype: Affected puppies may present with generalized ataxia (stumbling or lack of coordination), hypermetria (abnormal walking with front legs extending higher than normal), generalized weakness, exercise intolerance, episodic collapse, stiff gait and bunny hop movement.

Mode of Inheritance: Autosomal recessive

Alleles: N = Normal, CDMC = Cerebellar Degeneration-Myositis Complex

Breeds appropriate for testing: Nova Scotia Duck Tolling Retriever

Explanation of results:

•   Dogs with N/N genotype are expected to not have Cerebellar Degeneration-Myositis Complex. They cannot transmit this CDMC variant to any of their offspring.

•   Dogs with N/CDMC genotype have one copy of the CDMC variant and are expected to not have Cerebellar Degeneration-Myositis Complex, but are carriers. They will transmit this CDMC variant to 50% of their offspring. Matings between two carriers of CDMC may, on average, produce 25% of puppies with Cerebellar Degeneration-Myositis Complex.

•   Dogs with CDMC/CDMC genotypes are homozygous for the CDMC variant and will display signs of Cerebellar Degeneration-Myositis Complex

Turnaround Time
at least 15 business days; may be delayed beyond 15 business days if sample requires additional testing, or a new sample is requested.

$55 single test per animal ($5 discount on 3 or more dogs)

$25 as additional health test on same animal

Sample Collection

Dog DNA tests are carried out using cells brushed from your dog's cheeks and gums. The preferred cytology brushes are sent to you by mail, or you may provide your own brushes. For accepted alternative brushes, click here

We recommend waiting until puppies are at least three weeks old before testing.


Dog having its cheeks and gums brushed for DNA samples
Cheek and gum brushing technique for canine DNA sample collection


  1. Make sure the dog has not had anything to eat or drink for at least 1 hour prior to collecting sample.
  2. When swabbing puppies, isolate each puppy from the mother, littermates and any shared toys for 1 hour prior to swabbing. Puppies should not have nursed or eaten for 1 hour prior to collecting sample.
  3. If collecting samples from more than one dog, make sure to sample one dog at a time and wash your hands before swabbing another dog.
  4. Label brush sleeve with name or ID of dog to be sampled.
  5. Open brush sleeve by arrow and remove one brush by its handle.
  6. Place bristle head between the dog’s gums and cheek and press lightly on the outside of the cheek while rubbing or rotating the brush back and forth for 15 seconds.
  7. Wave the brush in the air for 20 seconds to air dry.
  8. Insert brush back into sleeve.
  9. Repeat steps 5 - 8 for each unused brush in sleeve on a fresh area of cheek and gums. Make sure to use and return all brushes sent by the VGL. In most cases, it will be 3 brushes per dog. If using interdental gum brushes, please note that the VGL requires 4 brushes per dog and only moderate or wide interdental gum brushes are accepted.
  10. Do not seal brushes in sleeve.
  11. Place all samples in an envelope and return to the address provided.


  • Do not collect saliva/drool – the key to obtaining a good sample is getting cheek cells on the swab
  • Do not rub swab on the dog’s tongue or teeth – this will result in poor quality sample
  • Do not collect a sample from a puppy that has recently nursed – the mother’s genetic material can rub off on the puppy’s mouth and contaminate the sample
Additional Details

Cerebellar Degeneration-Myositis Complex (CDMC) is a heritable condition that affects the cerebellum (the balance center of the brain) and muscles. It is inherited in an Autosomal recessive manner meaning a dog needs two copies of the affected allele to have the disease. The variant thought to cause this disease was identified by using a whole genome sequencing approach. This variant is considered to be a missense variant (p.Pro446Leu) in the SLC25A12 gene  that is predicted to impair the function of this protein. Variants in this gene cause similar defects in humans and mice. A different variant in the same gene is also thought to cause an inflammatory muscle disease in Dutch Shepherd dogs.  

Affected dogs present with neurological signs that include generalized ataxia (stumbling or lack of coordination) and hypermetria (walking with unusual range of motion, as if overreaching) beginning at 10 weeks to 6 months of age. Some affected dogs also displayed generalized weakness, exercise intolerance, episodic collapse, stiff gait, and hopping movement.

Additionally, affected dogs have elevated creatine kinase based on blood testing, which is indicative of abnormal muscle function. One affected dog was noted to have lesions on the brain specifically the cerebellum and lesions in the muscles that impact chewing. Follow up investigations indicated an inflammatory response was occurring in the muscles of affected dogs. The disease was named to reflect the lesions impacting both the brain and muscle.

To date, the condition has only been seen in the Nova Scotia Duck Tolling Retrievers (NSDTRs) and preliminary studies estimate that 7.1% of European and 2.7% of North American NSDTRs are carriers of the CDMC variant.

Testing recommendations: DNA testing for cerebellar degeneration-myositis complex can determine the genetic status of dogs. Dogs with one copy of the CDMC variant are normal but are carriers. Matings between two carrier dogs may, on average, produce 25% of puppies with cerebellar degeneration-myositis complex.