Genetic Testing

DNA , ORTHODIC and OPTOMOLOGIST TESTING ONLY TRULEY BENEFITS OUR MINIATURE AMERICAN SHEPHERDS.
Having these tests completed gives us an overall more informed picture of our dams and sires. Also it allows us to know that the puppies we have are not pre-disposed to having eye issues, hip issues, or allergies to specific medications. It is really a WIN WIN for our new puppy parents so they can have that piece of mind that I am a knowledgable breeder with our puppies as a priority!

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Eye Certification Registry Overview:
The purpose of the OFA Eye Certification Registry (CAER) is to provide breeders with information regarding canine eye diseases so that they may make informed breeding decisions in an effort to produce healthier dogs. CAER certifications will be performed by board certified (ACVO) veterinary ophthalmologists. Regardless of whether owners submit their CAER exam forms to the OFA for “certification,” all CAER exam data is collected for aggregate statistical purposes to provide information on trends in eye disease and breed susceptibility. Clinicians and students of ophthalmology, as well as interested breed clubs, and individual breeders and owners of specific breeds find this data useful.


O.F.A.  An Examination of Hip Grading Overview:
The evaluation of hips done by the Orthopedic Foundation for Animals falls into seven different categories. Those categories are Normal (Excellent, Good, Fair), Borderline, and Dysplastic (Mild, Moderate, Severe). Once each of the radiologists classifies the hip into one of the 7 phenotypes above, the final hip grade is decided by a consensus of the 3 independent outside evaluations. Examples would be: 
-Two radiologists reported Excellent, one Good—the final grade would be Excellent
-One radiologist reported Excellent, one Good, one Fair—the final grade would be Good
-One radiologist reported Fair, two radiologists reported Mild—the final grade would be Mild
The hip grades of Excellent, Good and Fair are within normal limits and are given OFA numbers. This information is accepted by AKC on dogs with permanent identification (tattoo, microchip) and is in the public domain. Radiographs of Borderline, Mild, Moderate and Severely dysplastic hip grades are reviewed by the OFA radiologist and a radiographic report is generated documenting the abnormal radiographic findings. Unless the owner has chosen the open database, dysplastic hip grades are not in the public domain. 

 


Other Genetic Testing We Do Overview:
1. Degenerative Myelopathy (DM) is a progressive neurological disorder that affects the spinal cord of dogs. Dogs that have inherited two defective copies will experience a breakdown of the cells responsible for sending and receiving signals from the brain, resulting in neurological symptoms. The disease often begins with an unsteady gait, and the dog may wobble when they attempt to walk. As the disease progresses, the dog's hind legs will weaken and eventually the dog will be unable to walk at all. Degenerative Myelopathy moves up the body, so if the disease is allowed to progress, the dog will eventually be unable to hold his bladder and will lose normal function in its front legs. Fortunately, there is no direct pain associated with Degenerative Myelopathy. The onset of Degenerative Myelopathy generally occurs later in life starting at an average age of about 8 years. However, some dogs may begin experiencing symptoms much earlier, some later, and a small percentage of dogs that have inherited two copies of the mutation will not experience symptoms at all. Thus, this disease is not completely penetrant, meaning that while a dog with the mutation is highly likely to develop Degenerative Myelopathy, the disease does not affect every dog that has the genotype. 

2. Cone Degeneration (CD) is an autosomal recessive disease that occurs in the German Shorthaired Pointer and Alaskan Malamute and several other breeds. Cone Degeneration disease causes day-blindness caused by a lack of cone function in the retina of the eye.
CD disease causes degeneration of the retinal "cones" that respond primarily to bright daylight, resulting in what is referred to as "day blindness." Cone-degenerate pups develop day-blindness and photophobia between 8 and 12 weeks of age, the age when retinal development is normally completed in dogs. Symptoms of CD are present only in bright light and the dog's vision is not affected in dim light. Cone Degeneration is inherited as a recessive disorder, so carrier dogs typically do not show any symptoms of the disease. These dogs can still pass on a copy of the mutation to any offspring, and any dog that inherits one copy of the mutation from each parent will be affected by cone degeneration. 

3. Canine Multifocal Retinopathy (CMR) is an autosomal recessive eye disorder known to affect Great Pyrenees, English Mastiffs, Bullmastiffs, Australian Shepherds, Dogue de Bordeaux, English Bulldogs, American Bulldogs, Coton de Tulears, Perro de Presa Canario, and Cane Corsos. The mutation causes raised lesions to form on the retina which alters the appearance of the eye but usually does not affect sight. The lesions may disappear, or may result in minor retinal folding. Symptoms of the mutation usually appear when a puppy is only a few months old, and generally do not worsen over time. CMR is recessive, so both parents would need to be carriers of the mutation to produce an affected puppy. "Clear" CMR dogs do not carry the mutation for the disorder. Breeding two clears or one clear and one carrier will not produce affected offspring, however if one parent is a carrier, a percentage of the offspring will be carriers. Therefore, it is useful to test for the presence of the CMR mutation before breeding. Additionally, since retinal defects can be caused by other conditions, testing can verify that a dog actually has CMR rather than some other eye condition. 

4. 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. Studies have shown that approximately 70 to 97 percent of rough and smooth collies in the United States and Great Britain have at least one copy of the mutation that causes CEA, and approximately 68 percent of Rough Collies in Sweden are affected. Border Collies are also subjected to this disorder, but at a lower percentage. CEA is also seen in Australian Shepherds, Shetland Sheepdogs, Lancashire Heelers, and other herding dogs.
Animal Genetics has developed a panel of six DNA markers called a "haplotype" to test for CEA. Animal Genetics is interested in developing a more comprehensive test to better distinguish those individual animals that may develop a more severe form of CEA from those that do not. Although we do not incorporate the genetic mutation Optigen claims to have an exclusive right to use into our panel, our test results using this haplotype of six DNA markers provides the same result.

5. Hereditary Cataracts (HSF4) 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. A mutation of the HSF4 gene is linked to a form of Hereditary Cataracts in Australian Shepherds. This mutation affects Aussies differently then Boston Terriers, French Bulldogs and Staffordshire Bull Terriers in that the disease is dominant but not completely penetrant. This means that only one copy of the mutation is necessary to predispose a dog to the disease. However, incomplete penetrance means that a dog that has this mutation will not always develop HC. Research suggests that the mutation makes a dog 12 times more likely to develop posterior bilateral cataracts at some point in their lifetime. It is likely that a secondary gene interaction occurs in the small percentage of dogs possessing the HC mutation but does not develop cataracts. This interaction is not yet understood. It should also be noted that not all cataracts are hereditary. Cataracts can also be caused by old age or injury. Also, cataracts that occur in different regions of the lens can also be familial, however, are not attributed to this gene mutation.

6. Multi-Drug Resistance Gene, (MDR1) codes for a protein that is responsible for protecting the brain by transporting potentially harmful chemicals away from the brain. In certain breeds, a mutation occurs in the MDR1 gene that causes sensitivity to Ivermectin, Loperamide, and a number of other 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. Dogs that are homozygous for the MDR1 gene (meaning that they have two copies of the mutation) will display a sensitivity to Ivermectin and other similiar drugs. These dogs will also always pass one copy of the mutation to all potential offspring. Dogs that are heterozygous (meaning they have only one copy of the mutation) can still react to these drugs at higher doses. Also, there is a 50% chance that a dog with one copy of the mutation will pass it on to any offspring. There are many different types of drugs that have been reported to cause problems. The following is a list of some of the drugs: Ivermectin (found in heartworm medications) Loperamide (Imodium over the counter antidiarrheal agent) Doxorubicin, Vincristine, Vinblastine (anticancer agents) Cyclosporin (immunosuppressive agent) Digoxin (heart drug) Acepromazine (tranquiliser) Butorphanol ("Bute" pain control).

Thanks for reading, from SoCal Mini Aussies!