dyserythropoietic anaemia & myopathy Syndrome (DAMS)
WHAT IS DAMS ?
In August 2022, a scientific paper was published which identified a genetic mutation that causes Dyserythropoietic Anaemia and Myopathy Syndrome (DAMS) in English Springer Spaniels. The study looked at a family of 26 show-type ESS from Sweden which included five affected with DAMS, two that died shortly before or after birth, and 19 unaffected. It also included two affected Australian dogs previously studied in 1991, which were distantly related to the Swedish dogs.
As with other genetic diseases such as Fucosidosis, DAMS is inherited through an autosomal recessive trait. Autosomal means that it can it can affect both males and females. Recessive means that for a dog to be affected, it must inherit two copies of the mutant gene (one from each parent).
WHAT ARE THE SYMPTOMS AND IMPACT OF DAMS ?
DAMS is an early onset high impact disease that significantly and increasingly affects the dog's quality of life. The affected Swedish dogs in the study had to be euthanised between the ages of 1-7 years.
Typical symptoms fall into two main categories:
Dyserythropoiesis: Defect in the development of red blood cells resulting in anaemia, with too few and small red blood cells, containing less haemoglobin than normal, affecting the ability to bind and transport oxygen. The bone marrow then increases production and sends out immature red blood cells that have a poorer ability to transport oxygen.
Polymyopathy: Impaired muscle function in several muscles. This may show as weakness, pain from the muscles, muscle wastage, limping gait, difficulty opening the mouth wide and chewing, and enlarged oesophagus (megaesophagus), causing difficulty swallowing, regurgitation and even life-threatening pneumonia.
Affected dogs begin to show symptoms shortly after birth and muscle wasting progresses over time until the dog can no longer walk, jump, eat, drink and move freely. It varies individually in how long it takes before the symptoms increase to such an extent that the dog can no longer live with the disease. Two of the Australian dogs studied in 1991 also had an enlarged heart (cardiomyopathy), but that was not observed in any of the Swedish dogs autopsied.
IS THERE A DNA TEST ?
Following the discovery of the DAMS mutation, a DNA test was developed and is available in the UK from Canine Genetic Testing (CAGT) and Laboklin laboratories. The test can be ordered online directly from their websites.
The DAMS mutation is recessive, which means it is safe to breed from carriers without risk of producing affected offspring, provided they are mated to dogs that are known to be clear of the mutation. This enables a wider selection of dogs with desirable characteristics (that otherwise appear healthy) to remain in the breeding pool to help maintain genetic diversity in the breed.
Although some of the symptoms overlap (muscle wastage, difficulty opening the mouth wide and chewing), it’s important not to confuse DAMS with MMM (Masticatory Muscle Myositis). Unlike DAMS, MMM is an autoimmune condition in which a specific type of muscle fibre found only in the chewing muscles of the jaw and skull is attacked and destroyed by the body’s own immune system. Sadly, there is no DNA test for MMM.
Note: DAMS has also been identified in Labrador Retrievers - although their mutation is in the same gene (EHBP1L1) as the ESS mutation, it is a different variant so the DNA tests are different for each breed.
THE STORY SO FAR AND WHERE DO WE GO FROM HERE?
A number of ESS breeders in Scandinavia have already used the DAMS DNA test and there appears to be a carrier rate of around 20% of those tested. Although there are substantial differences between the UK and Scandinavian ESS gene pools, there is also a significant crossover, with some UK show lines in the Scandinavian gene pool and vice versa. Therefore, a number of concerned UK breeders have now decided to test some or even all of their current stock and carriers have been found. At this stage, we simply have no idea of the overall mutation frequency in the UK ESS population, as it would need a large number of dogs from across the breed to be tested for us to have any meaningful indication. Yet at the same time, the wider breeding community is unlikely to be queuing up to test for a condition they've never heard of and which as far as they're concerned isn't a problem in the breed. It’s a classic chicken and egg situation.
That said, we obviously need to gather whatever data we can and our first priority was to ask the Kennel Club to introduce an official DNA Breed Test Scheme for DAMS (as we already have for Fucosidosis, PRA Cord1, AMS and PFK), so that all DAMS DNA test results would be automatically recorded on registration records and published on the KC website. This would make the results accessible to everyone and provide much needed data.
With the overwhelming support of the UK ESS Breed Clubs, we submitted a formal request to the KC in August 2023 and are pleased to confirm that an official ESS Breed Scheme was introduced with effect from 29th September 2023. Results of DAMS DNA tests carried out at KC approved laboratories from that date are now automatically forwarded to the KC for recording on registrations and publication in the next available Breed Records Supplement. They can also be viewed on the KC website Health Test Results Finder.
Results for dogs that were tested before the introduction of the official Breed Scheme can now also be recorded, but owners need to send the certified results to the Kennel Club themselves. Scanned copies of DAMS test certificates should be emailed to the KC at health.results@thekennelclub.org.uk. We strongly encourage owners to forward these results, whatever they were, so that they can be accessible to everyone and provide much needed data.
It's important to bear in mind that show-type ESS are only a tiny proportion of the overall ESS population in the UK. ‘Recommended’ health tests apply across the breed (we don’t have different lists for different sub-groups) and, with the information currently available, it’s too soon to know how common the DAMS mutation is across the ESS population as a whole. However, even if the mutation isn't common, DAMS is a devastating early onset and ultimately fatal disorder, so we would encourage and support any breeders who want to avoid any possibility of producing affected dogs, to use the DNA test for their own peace of mind as well as contributing towards much needed data.
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