Aussie Info Page 2

Australian Shepherds of all sizes have few health problems. The most common is the MDR1 gene mutation and several eye diseases. All of my breeding Aussies are either tested for the following genetic diseases or they are clear by parentage. Testing is done through Paw Print Genetics, Animal Genetics, GenSol, and/or Purdue University.

Multidrug resistance 1 (MDR1) is an inherited condition affecting several breeds of dogs, especially the herding breeds. This gene is found in nearly 50% of Miniature Aussies. This gene is responsible for removing certian drugs and toxins from the body, especially the brain. If the drugs can not be transported out of the body, then toxins build up and causes severe neurological problems that range from tremors, excess salivation, anorexia, and blindness to coma, seizures and sometimes death. Dogs with one copy of the gene are still at an increased risk of developing adverse reactions to certain drugs though dogs with two copies are most commonly seen. The drugs below can be lethal, even in low dosage, therefore, it is important to let your vet know if your dog is at risk for MDR1 before any drugs are administered.

Drugs known to cause neurological signs related to MDR1: acepromazine, butorphanol, doxorubicin, emodepside, erythromycin, ivermectin, loperamide, milbemycin, moxidectin, rifampin, selamectin, vinblastine, and vincristine. 

Progressive retinal Atrophy, progressive Rod-cone degeneration (PRA-prcd) is a late onset, inherited eye disease. PRA-prcd occurs as a result of degeneration of both rod cells which is important for vision in dim light and cone cells of the retina which is important for vision in bright light. Most affected dogs will not show signs until 3 to 5 years of age or later. Initially the dog will have problems seeing in the dim light first with the vision problems in bright light coming later. There are other inherited disorders of the eye that can appear similar to PRA-prcd but genetic testing will help clarify if the dog is affected with it or not. A dog has to have 2 copies of the gene to be afflicted with the PRA-prcd, if they only have 1 copy, they are considered to be a carrier and will be healthy of the disease. 

Hereditary cataracts is an inherited eye disease and most commonly show up between 2 and 7 years old with small cataracts that are visible at a veterinary exam. If a dog has one copy of the gene, (a carrier) they develop cataracts slowly and if a dog has two copies of the gene, they develop more rapidly progressing and severe. Note that not all cataracts are hereditary cataracts. 

Degenerative Myelopathy (DM) is an inherited neurologic disorder known to be carried by Miniature Australian Shepherds. Average age onset for this disease is approximately nine years. Affected dogs usually present in adulthood with gradual muscle atrophy and loss of coordination typically starts in the hind limbs due to the degeneration of the nerves. The condition is generally not painful, but it will progress until the dog is no longer able to walk. The gait of a dog affected with DM can be difficult to distinguish from the gait of dogs with hip dysplasia, arthritis of other joints of the hind limbs or intervertebral disc diseases. Late in the progression of DM, dogs may lose fecal and urinary continence, and the forelimbs may be affected with dogs losing the ability to walk 6 months to 2 years after the onset of symptoms. Dogs must have two copies to develop DM. If they have only one copy, (a carrier), they will remain healthy and show no signs of the disease. 

Neuroaxonal Dystrophy (NAD) is an inherited neurological disease that affects Australian Shepherds. The ago-of-onset is typically in young adults (2-4 years old.) Clinical signs begin very mildly, including a wide rear stance and intermittent abnormal gait, beginning in the pelvic limbs. They may have difficulty climbing stairs or jumping onto heights that shouldn't normally be a problem. The signs progress and worsen over time until the dog exhibits the abnormal gait all the time and may drag hind limbs. There is no treatment for NAD but medications may be prescribed to help control the symptoms. Other clinical signs can include head tremors, mental dullness, vision issues, incontinence, laryngeal paralysis and others. NAD is an autosomal recessive disease meaning a dog must have two copies of the mutated gene to be affected. If a dog inherits one copy of the gene, they are considered carriers and can pass it onto their offspring but not be afflicted with the disease. 

Currently only Purdue University is testing for NAD.