C118 - Canine Globoid cell leukodystrophy

Canine Globoid Cell Leukodystrophy is a storage disease, one of a relatively rare group of disorders in which there is a deficiency of a particular enzyme necessary for normal metabolic processes within the body. The result is an accumulation in cells ("storage") of whatever product the enzyme normally acts upon. Typically, animals with a storage disease are normal at birth, fail to grow as rapidly as littermates, and at a consistent age, develop progressive signs of a disorder of the nervous system which will ultimately be fatal. In Canine Globoid Cell Leukodystrophy, the lack of the enzyme galactocerebrosidase results in an accumulation of galactocerebroside, a component of myelin. This disrupts the cells that normally produce myelin, a fatty substance that coats nerve cells, serves as an electrical insulator and is crucial to the normal conduction of nerve impulses. The progressive loss of myelin in the white matter tracts of the nervous system (brain, spinal cord and/or peripheral nerves) causes a variety of clinical signs such as lack of coordination, tremors, and weakness. Puppies affected with this disease are normal at birth but grow more slowly than their littermates, and begin to to show signs of incoordination by 3 to 6 months. (In basset hounds the signs are seen later, between 1.5 and 4 years of age.) You may see tremors, a stiff gait, weakness, poor balance (falling to one side, stumbling), changes in behaviour or attitude, and vision changes. The disease is rapidly progressive over a few months in Cairn and West Highland White Terriers. The disease is invariably fatal, and affected dogs generally die or are euthanized before adulthood. The progression is slower in miniature poodles, over 2 to 4 years.

Canine Globoid Cell Leukodystrophy shows an autosomal recessive mode of inheritance; therefore two copies of the defective gene, one inherited from each parent, have to be present for a dog to be affected by the disease. Dogs with one copy of the defective gene and one copy of the normal gene - called carriers - show no symptoms but can pass the defective gene onto their offspring.

This DNA test provides reliable identification of dogs that carry mutant gene(s). This test allows a breeder to control the mutant gene frequency in Cairn and West Highland White Terriers thus preventing the production of puppies affected with Canine Globoid Cell Leukodystrophy. This DNA test accurately and specifically identifies normal, carriers (heterozygous) and affected dogs.