What is DM?
Degenerative Myelopathy (DM) is a progressive disease of the spinal cord in some older dogs. The disease has an insidious onset typically between the age of 8 and 14 years old. It begins with a loss of coordination (ataxia) in the hind limbs. The affected dog will wobble when walking or drag their feet. This can first occur in one hind limb and then affect the other. As the disease progresses, the limbs become weak and the dog begins to buckle and has difficulty standing. The weakness gets progressively worse until the dog is unable to walk. The clinical course can range from 6 months to 1 year before dogs become paraplegic. If signs progress for a longer period of time, loss of urinary and fecal incontinence may occur and eventually weakness will develop in the front limbs. Another key feature of DM is that it is mercifully not a painful disease.
DM is typically a late-onset disease, and dogs testing as At Risk that are clinically normal may still begin to show signs of the disease as they age. Some dogs testing At Risk did not begin to show clinical signs of DM until they were 15 years of age, while others never developed any signs at all. Research is still ongoing to try to figure out what triggers DM to begin.
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What is Von Willebrand Disease?
Von Willebrand Disease (vWD) is a genetic disorder that prevents normal blood clotting and can cause extended bleeding following injury or surgery. The disorder results from a deficiency or lack of sufficient von Willebrand factor (vWf) which functions as a binding protein during blood clotting. Three types of vWD have been identified in dogs to date and are known as vWD type 1, 2 and 3. Within these three types there are five different genetic mutations that are currently known that lead to canine vWD.
Von Willebrand's Disease type 1 (vWD1) results in reduction in normal levels of vWf to approximately 5-10% of normal. Since some vWf is produced in dogs homozygous for the vWD1 mutations, this form of the disorder is considered to be less serious than type 2 and 3. The mutation (G >A substitution) has variable penetrance and is recessive requiring two copies of the mutation in affected dogs. Typical symptoms of the disease encompass exessive or abnormal bleeding following injury or the presence of blood in various secretions (urine, feces, etc.)*
Careful selection of the sire and dam of a litter can go a long way in preventing these dreadful diseases from being passed down to the next generation.
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*Information about these diseases has been taken from GenSol Diagnostic Lab's & OFA's websites, with other websites being made available for you to research on your own. The images of corgis with DM have been taken from Google images.