Degenerative myelopathy-a progressive disease of the spinal cord in older dogs. The disease has an insidious onset typically between 8 and 14 years of age. It begins with a loss of coordination (ataxia) in the hind limbs. The affected dog will wobble when walking, knuckle over or drag the 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 continence may occur and eventually weakness will develop in the front limbs. Another key feature of DM is that it is not a painful disease.
GM2 Gangliosidosis-is an inherited Lysosomal Storage Disorder affecting dogs. Affected dogs have insufficient activity of the Enzyme hexosaminidase B, which is responsible for breaking down specific carbohydrates in the cells. As a result, there is an accumulation of a glycoprotein, GM2 ganglioside, in cells, especially cells of the brain and nervous system. Affected dogs typically present with symptoms of neurologic disease around 9 to 12 months of age. Symptoms include vision loss, difficulties walking, loss of balance, head tremors and vomiting. Once an affected dog begins to show signs of the disease, the disease progression is rapid and dogs usually die between the ages of 18 and 23 months.
Neonatal Encephalopathy with seizures-is an autosomal recessive disease of standard poodle puppies. Affected puppies are small and weak at birth. Many die in their first week of life. Those surviving past 1 week develop ataxia, a whole-body tremor and by 4 to 6 weeks of age, severe generalized clonic-tonic seizures. None have survived to 7 weeks of age. Cerebella from affected puppies were reduced in size.
Osteochondrodysplasia- this disorder is caused by genetic mutations, it is hereditary. Bone deformity and dwarfism can be detected very early in life. Dwarfism may be detected as early as fourteen days if a dog is not gaining weight at the same rate as its littermates, and skeletal deformities will begin to be visible around eight to twelve weeks of age. In extremely severe cases in which the deformity impedes bodily functions, dogs can die as early as days after birth.
Von Willebrand Disease 1 & 2-is a common, usually mild, inherited bleeding disorder in people and in dogs. It is caused by a lack of von Willebrand factor (vWF), which plays an essential role in the blood clotting process. Normally the body responds to an injury causing bleeding through a complex defense system. This consists of local changes in the damaged blood vessels, activation of blood cells called platelets, and the coagulation process. A reduction in von Willebrand factor leads to abnormal platelet function and prolonged bleeding times. Affected dogs are prone to bleeding episodes, such as nose bleeds, and generally experience increased bleeding with trauma or a surgical procedure. Three forms of the disease are distinguished based on vWF concentration and function. Dogs with Type I vWD (by far the most common) have mild to moderate bleeding abnormalities, depending on the level of vWF. The much rarer types II and III vWD cause severe bleeding disorders.How is it inherited?: The most common form (Type I vWD) is inherited as an autosomal trait with incomplete dominance. This means offspring may inherit the disorder if either parent carries the gene, but not all offspring will be affected to the same extent. Dogs with type I disease have reduced but measurable levels of Von Willebrand factor (1 to 60 per cent) and mild to moderate bleeding tendencies. Animals that inherit the gene for type I vWD from both parents (homozygotes) die before birth or shortly thereafter.
Progressive Retinal Atrophy, Progressive Rod-Cone Degeneration-The genetic disorder, prcd-PRA , causes cells in the retina at the back of the eye to degenerate and die, even though the cells seem to develop normally early in life. The “rod” cells operate in low light levels and are the first to lose normal function. Night blindness results. Then the “cone” cells gradually lose their normal function in full light situations. Most affected dogs will eventually be blind. Typically, the clinical disease is recognized first in early adolescence or early adulthood. Since age at onset of disease varies among breeds, you should read specific information for your dog. Diagnosis of retinal disease can be difficult. Conditions that seem to be prcd-PRA might instead be another disease and might not be inherited.
Ehlers-Danlos Syndrome (Variants 1 and 2) -1Ehlers-Danlos syndrome is an inherited Connective Tissue disease affecting dogs. Affected dogs typically present prior to 2 years of age with loose (hypermobile) joints, fragile blood vessels, and excessively elastic skin that is easily torn or bruised and can be stretched beyond limits seen in normal dogs. Dogs may display open wounds or scars from previous injuries and are at increased risk for joint dislocation.
Multidrug Resistance 1-Multidrug resistance 1, also called MDR1, is an inherited condition affecting several breeds of dogs, especially herding dogs or descendants of herding breeds. The Mutation in the ABCB1 gene associated with MDR1 causes dysfunction of P-glycoprotein, which is responsible for removing certain drugs and toxins from the body. Clinical signs are most commonly associated with distribution of the drug in the central nervous system. MDR1 is inherited in an autosomal incomplete dominant manner in dogs meaning that dogs only need to inherit one copy of the mutated gene to be at an increased risk of developing adverse reactions to certain medications. Though adverse reactions to certain drugs are most commonly seen in dogs having two copies of the mutated gene, Carrier dogs can also experience drug sensitivities and dosages need to be adjusted accordingly. Thus, dogs that have one or two copies of the mutation are considered at-risk for adverse drug reactions. If an at-risk dog is treated with one of several common drugs (see below*), they are at risk of developing neurologic symptoms that could range from tremors, excess salivation, anorexia, and blindness to coma and even death. Because of the defective ability to metabolize specific drugs, these drugs can be lethal even at low doses. The MDR1 mutation does not cause adverse effects in dogs unless the dog is exposed to these drugs. Therefore, veterinarians should be notified when a dog is at risk for multidrug resistance 1 prior to administration of any medications.