What is Fucosidosis in dogs?

Fucosidosis is a severe progressive and ultimately fatal inherited disease in dogs. It has an early onset with the typical age of the onset of symptoms of between 1.5 to 4 years old. A lack of an enzyme called alpha-L-fucosidase is responsible for this debilitating disease that leads to the accumulation of complex polysaccharides in the cells of the body, leading to the diminished capacity of these cells to perform their normal function. The outward clinical symptoms of Fucosidosis is normally seen when the cells of the brain and nervous system are impeded in their ability to function properly.


Genetics of Fucosidosis in dogs

Fucosidosis in dogs (just like it is in humans) is an autosomal recessive trait. This means that the defective version of the gene responsible must be inherited from both parents for the dog to be affected. Just one normal copy inherited from either parent will prevent the dog from becoming affected by Fucosidosis. Genetic testing via a DNA Disease Screen will detect if a dog carries either one, two or no copies of the defective gene.

What is the severity of Fucosidosis in dogs?

Fucosidosis is a very severe disease in dogs as it reduces the dog’s quality and length of life severly from the time of the onset of symptoms. Affected dogs will go through the range of symptoms and quite quickly progress to an early demise. There is no cure for this debilitating disease.

What are the symptoms of Fucosidosis in dogs?

While the range of symptoms can vary greatly depending on which of the cells in the body have the greatest amount of accumulation of the complex polysaccharides, usually it is the central nervous system which is the first to display a lack of function. This is why typical symptoms of Fucosidosis are often in line with a degrading nervous system. Typical symptoms include a change in behaviour or temperament, loss of balance, weight loss, a loss of learned behaviour and a loss of sensory function that gets worse as the disease progresses including deafness and sight impairment. Unfortunately, the symptoms of this disease progress very quickly and becomes fatal for the affected dog in a short amount of time.

Diagnosis of Fucosidosis in dogs

Diagnosis of canine Fucosidosis can be made definitively with a DNA test to check for mutated copies of the gene responsible. This same test will let the owner of a dog showing no symptoms all know if their dog will be affected, or if they are a carrier of the disease and could pass it on to puppies bred from this dog. The DNA Disease Screening test will also allow owners to determine if their dogs are clear of Fucosidosis to make better choices when the time comes to breed their dogs.

Treatment of dogs with Fucosidosis

There are no treatments available that will greatly extend the life of a dog affected by Fucosidosis at this stage and treatment is limited to making the life of the affected dog as comfortable as possible by treating the progressing symptoms.


Hartley WJ, Canfield PJ, Donnelly TM (1982). A suspected new canine storage disease. Acta Neuropathologia 56: 225-232

Image Credit: Dr Marc E. Tischler – University of Arizona  https://disorders.eyes.arizona.edu/disorders/fucosidosis

Skelly BJ, Sargan DR, Herrtage ME, Winchester BG (1996). The molecular defect underlying canine fucosidosis. Journal of Medical Genetics 33: 284-288

Kelly WR, Clague AE, Barns RJ, Bate MJ, MacKay BM (1983). Canine alpha-L-fucosidosis: a storage disease of Springer Spaniels. Acta Neuropathologica 60: 9-13

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