Three main causes of Exocrine Pancreatic Insufficiency in dogs are-
- Pancreatic Acinar Atrophy (PAA), which is an inherited disease causing a gradual loss of enzyme-producing cells.
- 1a. Pancreatic Acinar Atrophy used to be considered an autosomal recessive condition in dogs: Note: This has been challenged recently, though, and it’s important to know that research is being done into it being a Polygenic condition, which means it may be influenced by multiple genes, rather than a single gene.
- Chronic Pancreatitis (CP), which is an inflammatory condition that damages the pancreas.
- Pancreatic Neoplasia (cancer), which can disrupt normal pancreatic function.
Inherited EPI is developed via an autosomal recessive gene: 50% of each dog’s genetic traits are shared, and you will have a 1 in 4 ratio in a litter, depending on which gene is shared. Note: In dogs, an autosomal recessive gene means a specific gene for a genetic condition that is located on a non-sex chromosome and requires TWO copies of the mutated gene-ONE from EACH parent – for the dog to be affected by the disorder. A dog with only one copy of the mutated gene is called a carrier; it does not show signs of the disease but can pass the gene on to its offspring.
PLEASE NOTE: There is currently NO health test available that can advise you if a stud dog or Dam is a carrier of the EPI gene creating PAA – (inherited EPI). You will only know when the TWO dogs produce EPI puppies!! Neither of these parent dogs should be bred again, as you will not know if a new partner is carrying the affected gene, and ethically, you wouldn’t want to create more EPI puppies.
Key terms and concepts:
Autosomal: The gene is found on one of the numbered, non-sex chromosomes, rather than the X or Y sex chromosomes.
Recessive: For the disorder to develop, a dog MUST inherit two copies of the mutated gene.
Carrier: A dog that has one copy of the recessive, mutated gene but does not show any signs of the disease.
Homozygous recessive: A dog that has two copies of the mutated gene and is therefore affected by the disorder.
How it works in breeding:
Dam – Clear (two normal genes) mated with Sire – Clear (two normal genes). Only clear offspring: All puppies will inherit two normal genes and be clear of the specific genetic condition.
Dam – Carrier (one mutated gene) mated with Sire – Clear (two normal genes). Risk of carrier offspring – About 50% (half) of the puppies will likely inherit one mutated gene and become carriers, while the other half will be Clear (no copies of the mutated gene)
Dam – Carrier (one mutated gene) mated with Sire – Carrier (one mutated gene) Risk of affected offspring: About 25% (one in four) of the puppies will likely inherit two mutated genes and be affected by the disorder.
Age of diagnosis – Dogs with hereditary exocrine pancreatic insufficiency (PAA) are often diagnosed in German Shepherds and Rough Collies and typically present at a younger age (often under 4 years old) than other breeds. While EPI can affect dogs at any age, the onset of signs for PAA-related hereditary EPI is most common in young adulthood, 2-3 years old.
Other breeds: While EPI can occur in any breed, it tends to appear in middle-aged to older dogs when the cause is chronic pancreatitis rather than PAA.
Why the Age Variation? Pancreatic Acinar Atrophy (PAA): The most common cause of hereditary EPI is PAA, which is a genetic condition where the pancreas deteriorates. It can take up to four years for the pancreas to completely stop working, but most are fully dysfunctional by 2.5 – 3 years old.
Chronic Pancreatitis: In some cases, EPI results from chronic inflammation and damage to the pancreas, a condition that can affect dogs of any age but is often seen in middle-aged to older dogs.
Key Takeaway for breeders: If a puppy you have bred, especially a German Shepherd or Rough Collie, shows signs of weight loss despite a good appetite, large, greasy, foul-smelling stools, and poor coat condition, it could be hereditary EPI. It is advisable to get a veterinarian to perform a serum cTLI test to diagnose EPI and determine the appropriate treatment.
ANY dog that produces puppies that have the PAA variant of EPI (the SIRE AND DAM) should not be bred from again. NO health test can identify if your dog is a carrier; the only way to tell is if they produce EPI puppies. Do the right thing and don’t risk creating this condition again. Withdraw the dog from your breeding programme.
Please do not deal with this by putting your head in the sand and denying the possibility of one of your puppies having EPI. PLEASE advise the puppy buyer to get a cTLI test as soon as possible and if the numbers are low (under 10) suggest to them to discuss with their vet the possibility of hereditary EPI. Please note: EPI can skip a generation or two.
Owners: If you are the owner of an EPI dog that was diagnosed at a younger age, it is likely to have the inherited type. It is IMPERATIVE to let your breeder know. And one would hope that the breeder advises all other puppy buyers so they can see their vet sooner, rather than later.
There is no bonus to catching EPI early, but more value in catching it in time. The longer it is left, the more likely your dog will end up with organ failure and die from starvation.