Intestinal cobalamin malabsorption, also known as Amnionless Deficiency, Cobalamin Deficiency, Imerslund-Grasbeck Syndrome (IGS), and Vitamin B12 Deficiency, is an inherited disease found in the Australian Shepherd and related breeds (Miniature Australian Shepherd, Toy Australian Shepherd, Miniature American Shepherd). The disease is inherited in a recessive fashion and as such, dogs that inherit two copies of the mutation are at risk for the disease. The disease is caused by the inability 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 require treatment with cobalamin supplementation throughout their life.
Because of the severity of this condition and the fact that it is treatable, this test has been added to the breed-specific panels for Australian Shepherds and related breeds ...