What is globoid-cell leukodystrophy?
Globoid-cell leukodystrophy (GCL), also called Krabbe disease or lysosomal storage disease, is a rare disease caused by a mutation in a dog’s DNA. It results in abnormal processing and storage of an enzyme critical for producing myelin, the substance that coats and protects the nerves throughout the brain and spinal cord. The myelin sheath develops until dogs are about 18 months of age. When the myelin is defective, the nerve cells are damaged, destroyed, and fire randomly, resulting in tremors, staggering, weakness, and incoordination. GCL is uniformly fatal.
When do clinical signs appear?
Young puppies do not generally show signs of GCL. When signs emerge, typically between one and six months in small terriers, the puppy will begin having tremors and overall muscle weakness and will seem to lose control over his legs. They stop growing normally, and they may develop vision problems. Larger breed dogs with GCL may not show signs until between 18 months and five years of age.
In addition to the neuromuscular symptoms, affected puppies will develop behavior changes, dementia, lack of appetite, starvation from an inability to eat, and urinary and fecal incontinence. Most dogs must be euthanized due to their neuromuscular decline about two to six months after the onset of clinical signs.
Are certain breeds more susceptible to GCL?
Breeds most commonly affected by GCL include the West Highland White Terrier, Cairn Terrier, Bluetick Coonhound, Beagle, Poodle, Basset Hound, Pomeranian, and Irish Setter.
How is this disease diagnosed?
A definitive diagnosis of GCL can be made with a blood test in Cairn Terriers, West Highland White Terriers, and Irish Setters. GCL is caused by a recessive gene, meaning both parents must be carriers. Even with two recessive carriers, not all litters or all puppies in a particular litter will have GCL. They may, however, be carriers. Reputable breeders work to identify carriers and eliminate them from their breeding program.