Multi-Drug Resistance Gene (MDR) codes for a protein that is responsible for protecting the brain by transporting potentially harmful chemicals away. In certain breeds, a mutation occurs in the MDR1 gene that causes sensitivity to Ivermectin, Loperamide, and a number of other common drugs. Dogs with this mutation have a defect in the P-glycoprotein that is normally responsible for transporting certain drugs out of the brain. The defective protein inhibits the dog's ability to remove certain drugs from the brain, leading to a buildup of these toxins. As a result of the accumulation of toxins, the dog can show neurological symptoms, such as seizures, ataxia, or even death.
Reprinted from.. www.animalgenetics.us/Canine/Genetic_Disease/MDR1.asp
Please credit Litton's Aussies if you use my MDR1 information photo.. Thank you!!
Hereditary Cataracts (HC) are a clouding of the lens of the eye caused by a breakdown of tissue in the eye. This condition generally results in an inability to see clearly and can cause total blindness. In canines, cataracts are often familial; this type is known as Hereditary Cataracts. A mutation in the HSF4 gene causes this type of cataracts in several breeds of dogs. In this case, the dog is typically affected bilaterally, in that both eyes are affected by the cataracts. The cataracts associated with HSF4 also occur in the posterior region of the lens. They usually start by being small and grow progressively, though the speed of growth is highly variable. Some cataracts will grow so slowly that the dog's vision remains relatively clear, while others will grow such a way that the dog will quickly go blind. Corrective surgery is possible, though it is costly and is not always effective.
Reprinted from.. www.animalgenetics.us/Canine/Genetic_Disease/HC.asp
Progressive Retinal Atrophy (PRA): An Overview Progressive Retinal Atrophy, or PRA, is a condition of the retina in the eye. PRA encompasses many diseases which all progress over time and eventually lead to blindness. The retina works in the eye much as the film in a camera works. It changes the light it receives into images which are then sent down the optic nerve to be interpreted by the brain. When a dog has PRA the retina either stops developing prematurely or the light receptors degenerate early in life. With this condition both eyes are equally affected. The different forms of PRA vary in the age at which they first develop and in the rate at which they progress. Cases can be early onset with rapid progression to late onset with slow progression or any combination of the sorts. Every case is different and definite age of onset or how quickly progression will occur can never be known for sure.
Reprint from... www.akcchf.org/canine-health/your-dogs-health/disease-information/progressive-retinal-atrophy.html
Collie Eye Anomaly (CEA) is a inherited bilateral eye disease common in a number of breeds of dogs. The disorder causes abnormal development in layers of tissue in the eye under the retina called the choroid. These changes cause what is referred to as Choroidal Hypoplasia. The abnormal choroid appears pale and translucent. In most cases CEA is present at birth and can be detected in puppies as young as 4-8 weeks of age. There is currently no treatment for this disease.
Reprint from.. www.animalgenetics.us/Canine/Genetic_Disease/CEA.asp
Degenerative Myelopathy (DM) is a progressive neurological disorder that affects the spinal cord of older dogs. Reprint from.. www.animalgenetics.us/Canine/Genetic_Disease/DM.asp
Great atricle about DM Degenerative myelopathy – my unpopular view
Many are testing for DM in aussies. They are not on the list at OFA, At this time they cant prove the DM test works for Aussies. You can read more here... www.offa.org/dnatesting/dmotherbreeds.html
Intestinal cobalamin malabsorption (Australian shepherd type) is an inherited disease affecting Australian shepherds. Affected dogs are unable to make adequate amounts of a protein that plays a role in absorption of certain nutrients from the intestinal tract and kidneys, including the B vitamin, cobalamin. Affected dogs have increased levels of methylmalonic acid in their urine (a sign of cobalamin deficiency) after weaning, but symptoms of disease may not be recognized by owners for months or years. Symptoms of disease include anorexia, lethargy, poor weight gain, poor muscle mass, and in rare circumstances, a severe neurological dysfunction called hepatic encephalopathy that can lead to altered mental state, seizures, coma and death. Affected dogs have an increase in certain proteins in their urine, and have decreased synthesis of blood cells resulting in Anemia and decreased numbers of neutrophils. Affected dogs require cobalamin supplementation for life that results in disease remission for most animals within a few weeks. Though not associated with clinical disease, affected dogs will continue to pass increased amounts of certain proteins in the urine even with cobalamin supplementation.
Still working on getting links and correct information for all testing.