Find out if your English Springer Spaniel could develop Fucosidosis at CAGT.

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Results from this test will be reported as detailed in the Registry Reporting list.


Fucosidosis is a lysosomal storage disease which results from the enzyme alpha-L-fucosidosis being defective or absent. This results in the impaired breakdown, and therefore accumulation of complex sugars, primarily in cells of the nervous system. Unfortunately, the disease is progressive and fatal.

Affected dogs typically present with symptoms between the ages of 11 months and four years. Clinical signs observed include ataxia (wobbly gait), loss of balance, hearing problems, loss of learned behaviour, difficulty swallowing and weight loss.

Autosomal Recessive

The 14 nucleotide deletion in the gene called Alpha-L-Fucosidase 1 (FUCA1) that causes Fucosidosis in English Springer Spaniel is recessive.  This means that dogs that carry two copies of the mutation (homozygotes) will almost certainly develop Fucosidosis during their lives.  Dogs that carry a single copy of the mutation (also known as carriers or heterozygotes) will not develop Fucosidosis as a result of the FUCA1 mutation, but they will pass the mutation onto about half of any offspring they have.  Breeding dogs that will not develop Fucosidosis should be the breeder’s priority, with a reduction in mutation frequency within the whole breed being the secondary, longer-term target.

Carriers can be bred from safely, provided they are mated to a dog that has also been tested and is clear of the FUCA1 mutation (i.e. carry no copies of the mutation). If a carrier is mated to a clear dog approximately half of the resulting puppies will also be carriers, so should be tested themselves prior to breeding.  Breeding carriers to tested, clear dogs is safe, in terms of avoiding dogs affected with Fucosidosis, and will help to maintain the genetic diversity of a breed. It is therefore encouraged, particularly in the first few generations following the availability of a new genetic test, so that other desirable characteristics and traits can be preserved before the frequency of the disease mutation within the breed is gradually reduced.

Gene FUCA1
Variant 14 nucleotide deletion, c.379_392del, p.A127Vfs*26
Assay Type Variant Specific
Inheritance Autosomal Recessive
Severity Moderate-Severe: The welfare of affected animals is significantly affected and life expectancy is usually reduced.

Occhiodoro T and Anson DS. (1996) Isolation of the canine α-L-fucosidase cDNA and definition of the fucosidosis mutation in English Springer Spaniels. Mammalian Genome. 7(4): 271-274. DOI: 10.1007/s003359900081.

Skelly BJ, Sargan DR, Herrtage ME, et al. (1996) The molecular defect underlying canine fucosidosis. Journal of Medical Genetics. 33(4): 284-288. DOI: 10.1136/jmg.33.4.284.