Hereditary Cobalamin (Vitamin B12) Malabsorbtion in Australian Shepherds by C.A. Sharp Cobalamin malabsorbtion is a serious and potentially life-threatening metabolic disease in puppies and young dogs. Fortunately, with proper diagnosis and relatively inexpensive treatment, affected dogs can be kept in remission throughout their lives. The disease was identified by John C. Fyfe, of the University of Michigan, and his colleagues at the University of Pennsylvania. In affected dogs, the lining of the lower intestine will not absorb vitamin B12. It is caused by a mutation of a gene called Amnionless (Amn) and affects dogs that inherit two copies, one from each parent. Signs of cobalamin malabsorbtion usually start around 6-12 weeks of age, but may not be noted until the dog is an adult. The disease can cause a wide range of clinical problems, including lack of appetite, lethargy, failure to thrive, wasting, vomiting, seizures, or general ill-health. The most serious complications include abnormalities of the blood and nervous system that are lethal if untreated. It is common for B12 deficiency to be mistaken for another disease because of the varied clinical signs and the fact it is not well-known that it is present in Aussies. The signs can mimic those of liver shunts, early-onset epilepsy and some immunodeficiency diseases. Veterinarians presented with dogs exhibiting any of these signs m may find led low counts of red and white blood cells, platelet and neutrophils; excess blood ammonia; and protein in the urine when they perform standard diagnostic tests. If these results are found, there are two diagnostic tests for cobalamin malabsorbtion. Texas A&M offers a blood test that determines serum cobalamin. However, the levels revealed by this test may not be diagnostic. The University of Pennsylvania’s methylmalonic acid (MMA) test, which looks for the accumulation of this abnormal metabolite in a urine sample. (Note for veterinarians: The sample must be shipped on ice overnight.) Click HERE to open a copy of the test form. Treatment of affected dogs consists of subcutaneous vitamin B12 injections every 2-4 weeks for life. Response is rapid and results will be seen in a matter of days. Serious cases may require more intensive B12 therapy and supportive care for up to 10 days. Because cobalamin malabsorbtion is hereditary, it can have a serious impact a breeding program. Fortunately, there is already a DNA test available through the University of Pennsylvania. Results are confidential and will be provided only to the owner or veterinarian. To download the DNA test form, click HERE. The DNA test will identify not only carriers, but affected dogs before they exhibit signs of the disease. With the test, breeders can identify affected dogs before they might be bred and continue to use carrier dogs and preserve their desirable traits without ever producing another affected puppy. At this point frequency of this disease in Aussies is unknown, but cases have been identified over the past decade in North America, Europe and Australia. ASHGI would also like to track specific cases to create a confidential database on affected and carrier dogs. Submit Submit DNA and/or diagnostic blood or urine test results and a pedigree for each affected or carrier dog. E-mail scanned copies to: 51ca @ ashgi.org Or Fax: 559 485-2136 Or mail: ASHGI 730 E. Weldon Ave. Fresno, CA 93704-6135 If you have puppies or young dogs that are displaying any of the signs listed above, ask your veterinarian to consider possible B12 deficiency. When cases are identified, notify the owners of both parents as they will be carriers. If you learn your dog is a carrier, test relatives so you will know their status. Doing these things will help prevent the production of more affected puppies and save lives. To contact the University of Pennsylvania directly: 215 898-8894