About Von Willebrand Disease (VWD1)
Von Willebrand Disease I (VWDI) is an inherited bleeding disorder affecting Pembroke Welsh Corgis. Dogs affected with VWDI have less than half of the normal level of von Willebrand coagulation factor (vWf), which is an essential protein needed for normal blood clotting. There is variability in the amount of vWf such that not all dogs with two copies of the Mutation are equally affected. Dogs that have less than 35% of the normal amount of VWf generally have mild to moderate signs of a bleeding disorder. Affected dogs may bruise easily, have frequent nosebleeds, bleed from the mouth when juvenile teeth are lost, and experience prolonged bleeding after surgery or trauma. Less often, the bleeding may be severe enough to cause death. Due to the variable severity of the disorder, affected dogs may not be identified until a surgery is performed or trauma occurs at which time excessive bleeding is noted. Veterinarians performing surgery on known affected dogs should have ready access to blood banked for transfusions. Most dogs will have a normal lifespan with this condition despite increased blood clotting times.
The Mutation of the VWF gene associated with von Willebrand disease I has been identified in the Pembroke Welsh Corgi. Though the exact frequency in the overall Pembroke Welsh Corgi population is unknown, 37% of the Pembroke Welsh Corgis tested were carriers of the mutation and 6% were at-risk/affected.
Genetic testing of the VWF gene in Pembroke Welsh Corgis will reliably determine whether a dog is a genetic Carrier of von Willebrand disease I. Von Willebrand Disease I is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs rarely have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the VWF gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms may be mild in affected dogs, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Pembroke Welsh Corgis that are not carriers of the mutation have no increased risk of having affected pups.
About Exercise-Induced Collapse (EIC)
Exercise-Induced Collapse (EIC) is an inherited neuromuscular disorder affecting Pembroke Welsh Corgis. EIC presents as exercise intolerance in apparently healthy dogs. Affected dogs are usually diagnosed before two years of age and appear normal during low to moderately strenuous activity. However, shortly after 5-20 minutes of strenuous exercise affected dogs will begin to walk with a wobbly, uncoordinated gait that often only affects the hind limbs. Dogs remain mentally alert and are not in pain during episodes of EIC. In some circumstances, the symptoms of EIC can progress to full body weakness with low muscle tone (flaccid paralysis), confusion, loss of consciousness, seizures and very rarely, death. The episodes typically last 5-10 minutes and most dogs will completely recover within 15-30 minutes.
Degenerative Myelopathy (DM)
The Mutation of the DNM1 gene associated with exercise-induced collapse has been identified in the Pembroke Welsh Corgi. Though the exact frequency in the overall Pembroke Welsh Corgi population is unknown, 14% out of 94 Pembroke Welsh Corgis tested were carriers of the mutation and 2% were at-risk/affected.
Genetic testing of the DNM1 gene in Pembroke Welsh Corgis will reliably determine whether a dog is a genetic Carrier of exercise-induced collapse. Exercise-Induced Collapse is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the DNM1 gene mutation. Reliable genetic testing is important for determining breeding practices. Because this mutation shows Variable Expressivity, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Pembroke Welsh Corgis that are not carriers of the mutation have no increased risk of having affected pups.
Please keep in mind, although many breeders are starting to, or are already, taking the necessary steps to breed away from this disease, that regardless what a dog tests, it’s still a GOOD DOG. Just because a dog may be At Risk, doesn’t make them a lesser or “dirty dog” – they just unfortunately may potentially develop the disease as they get older. Not ALL DM At Risk dogs are guaranteed to develop the disease, an At Risk dog may pass from other ailments or become compromised from other natural causes and never develop the disease. There are always unknown genetic diseases that are yet to be discovered or have developed testing yet. Many people become overly critical of finding the genetically perfect dog (or animal of any kind) and forfeit many far more important things such as conformation, intelligence and temperament – just remember there’s a fine balance to everything.
Written by Ashley Thomas
Morgy’s Story
If you chose to use the links below you will be introduced to Morgy an 11 year old Corgi, Morgy, has Degenerative Myelopathy. DM is a disease of the spine that is common in many breeds. This video is what we are doing through exercise and supplements to help Morgy with this incurable disease. The follow up video is one year later and shows the progression of the disease.