1. DM result: n/DM — what does it mean?
The result n/DM means that your male dog is a carrier of the mutation associated with degenerative myelopathy (DM).
- n is the normal, “healthy” copy of the gene.
- DM is the mutated, “defective” copy of the gene.
Your dog has one normal copy of the gene and one mutated copy. This condition is called heterozygous carrier status.
Most importantly, a carrier dog (n/DM) will NOT develop degenerative myelopathy. This is an autosomal recessive disease, which means that for it to develop, a dog must have two mutated copies of the gene (DM/DM).
2.Application to French Bulldogs: Is the Statement True?
Your doubt is justified. You are right.
The SOD1 gene mutation is the cause of DM in many breeds (e.g., German Shepherds, Corgis, Boxers). However, the link between this mutation and the actual development of the disease in French Bulldogs is unproven. The risk is considered insignificant.
Fact from Reports:
“In some breeds, there is a low risk of the dog developing the disorder.”
French Bulldogs belong to these breeds. The presence of the DM/DM mutation does not guarantee disease development. Clinical cases of DM in Bulldogs associated with this mutation are extremely rare or undocumented.
Conclusion: This result does not pose a significant threat to your dog’s health.
3. Is this a problem for future litters?
Yes, this is an important point to consider when planning breeding.
Since your male dog is a carrier (n/DM), he can pass on the mutated DM gene to his puppies. The risk only arises if he is mated with a female dog who is also a carrier (n/DM) or, worse, affected (DM/DM).
Let’s look at the possible combinations:
Male (carrier n/DM) x Female (status)
Possible outcomes for puppies
Clear (n/n)
50% of puppies will be clear (n/n), 50% will be carriers (n/DM). No puppies will be affected.
Carrier (n/DM)
25% clear (n/n), 50% carriers (n/DM), 25% at risk of disease (DM/DM).
Affected (DM/DM)
All puppies will be carriers (n/DM).
Conclusions and recommendations for the breeder:
- This is not a health problem for your male dog. He will live a long and full life without the risk of developing DM.
- For breeding, this is a manageable situation. A responsible breeder should always take into account the genetic status of the parents.
- Mandatory condition: Your male dog should only be mated with a female dog that has been tested for DM and has a result of n/n (clear).
- Under no circumstances should he be mated with a female carrier (n/DM) or with unknown status, as this may result in the birth of puppies with the DM/DM genotype, which, although it does not guarantee disease in French Bulldogs, is undesirable from a responsible breeding standpoint.
Conclusion and Breeder Responsibility
Health:
- Do not worry about the male’s health.
- The DM n/DM result for a French Bulldog is not a medical problem.
Responsibility:
- The stud dog owner must responsibly choose a partner.
- Goal: Prevent the gene’s spread within the breed.
Mandatory Actions:
- Check the genetic tests of potential partners.
- Planning a litter: consult an experienced breeder or a veterinary geneticist.