HealthTesting

Canine Fucosidosis is a disease which is severe, progressive and ultimately FATAL.

It is characterised by deteriorating signs of the nervous system that progress over a period of several months, sometimes from an early age. Signs include inco-ordination and ataxia (loss of control of movement), change in temperament, loss of learned behaviour, loss of balance, apparent deafness, visual impairment and varying degrees of depression. The inco-ordination and ataxia affects all four legs and is mostly evident when affected animals are walking on slippery surfaces or attempt more complicated movements such as turning. In addition, affected dogs lose weight and may suffer from swallowing difficulties and sometimes regurgitation of food.

The disease, which affects young adults, usually between 18 months and 4 years of age, is caused by the absence of an enzyme called alpha-L-fucosidase. This enzyme is one of many required to break down complex compounds into simple molecules that the body can use. When this enzyme is absent, the pathway is blocked and the more complex compounds build up in the cells of the affected animal, accumulating in the lymph nodes, liver, pancreas, kidney, lungs and bone marrow. However, it is the accumulation in the brain and peripheral nerves that is most important, since it interferes with normal function, giving rise to the clinical signs described, eventually resulting in death.

Canine Fucosidosis can affect all English Springer Spaniels, whether they are of ‘field trial', ‘working', ‘show' or ‘pet' origin. Don't let anyone tell you otherwise!

The condition is inherited through an autosomal recessive trait and has been reported by ESS owners/breeders from all over the world.

All responsible Breeders should use the DNA Test which has been available since 1997 which:

· Can be undertaken at any age and needs only to be done once in a dog's lifetime.

· Makes it safe, for the time being at least, for the breed to use identified Carriers

A Kennel Club Breed Scheme for Fucosidosis has been in operation since 2005, with results now recorded in the KC's Quarterly Breed Records Supplements, on KC Registration documents and on the KC's Website, thus ensuring that the audit trail of information about a ‘genetically clear' for Fucosidosis English Springer is not lost.

Progressive retinal atrophy (PRA) is a term for retinal degenerations occurring in many breeds of dog including the English Springer Spaniel.

Many forms of PRA exist, each form being confined to one or a few breeds only. The disease results in a degeneration of the light-sensitive membrane at the back of the eye - the retina - resulting in loss of vision, and often leading to blindness. The disease is caused by a change to a gene involved in sight. This change, or mutation, occurred spontaneously, but once in the population has been inherited from generation to generation like any other gene. The mutation upsets the delicate processes involved in vision and causes the long-term degeneration seen. There is currently no treatment for the disease.

Breeding stock are regularly checked by eye examination, although this can only pick up affected dogs after symptoms have developed and will never detect the symptomless carriers. Research at the Animal Health Trust has identified a genetic change underlying PRA in English Springer Spaniels. The mutation has been designated cord1 and is a cone-rod degeneration affecting both these types of cells which are crucial to vision in the retina.

Breeders are sent results identifying their dog as belonging to one of three categories:

Inheritance: PRA (cord1) is an autosomal recessive disorder. Crossing the three genotypes - clear, carrier or affected - will produce the following litters:

Parents	Litters
clear x clear	all clear
clear x carrier	approximately 50% clear 50% carriers
clear x affected	all carriers
carrier x carrier	approximately 25% clear, 50% carriers 25% affected
carrier x affected	approximately 50% clear 50% affected
affected x affected	all affected

Familial Nephropathy leads to progressive and irreversible renal failure between 6 months to 2 years. The first clinical signs are excessive water consumption, excessive urine volume, a slowdown in growth, weight loss, reduced appetite, vomiting and diarrhoea, Kidney dysfunction moving inexorably towards a premature death of the animal.

About 11% of English Cocker Spaniels in Europe are carriers of the genetic mutation responsible of Familial Nephropathy. Without testing, a breeder can mate without noticing a male « carrier » and a female « carrier » and produce a litter containing affected puppies.

A puppy can be affected if his two parents are carriers of the mutation. Breeders unaware of Familial Nephropathy can mate stud dogs and brood bitches carriers of the mutation and produce affected puppies.

A DNA test called FN, can detect the Familial Nephropathy of the English Cocker Spaniel with a reliability above 99%

Familial nephropathy leads to an early and fatal renal failure. Around 11% of English Cocker Spaniels are carriers of the genetic mutation responsible for the disease.

The reliable DNA test available can screen stud dogs and brood bitches, in order to adapt mating and avoid birth of affected puppies and spread of the disease in the breed.

The genetic disorder, prcd-PRA , causes cells in the retina at the back of the eye to degenerate and die, even though the cells seem to develop normally early in life.

The “rod” cells operate in low light levels and are the first to lose normal function - Night blindness results. Then the “cone” cells gradually lose their normal function in full light situations. Most affected dogs will eventually be blind. Typically, the clinical disease is recognized first in early adolescence or early adulthood.

Since age at onset of disease varies among breeds, you should read specific information for your dog. Diagnosis of retinal disease can be difficult. Conditions that seem to be prcd-PRA might instead be another disease and might not be inherited.

OptiGen’s genetic test assists in making the diagnosis. It’s important to remember that not all retinal disease is PRA and not all PRA is the prcd form of PRA. Annual eye exams by a veterinary ophthalmologist will build a history of eye health that will help to diagnose disease.

Prcd-PRA is inherited as a recessive trait. This means a disease gene must be inherited from each parent in order to cause disease in an offspring. Parents were either “carrier” or affected. A carrier has one disease gene and one normal gene, and is termed “heterozygous” for the disease. A normal dog has no disease gene and is termed “homozygous normal” – both copies of the gene are the same. And a dog with two disease genes is termed “homozygous affected” – both copies of the gene are abnormal.

It’s been proven that all breeds being tested for prcd-PRA have the same disease caused by the same mutated gene. This is so, even though the disease might develop at different ages or with differing severity from one breed to another.

Although prcd-PRA is inherited, it can be avoided in future generations by testing dogs before breeding. Identification of dogs that do not carry disease genes is the key. These "clear" dogs can be bred to any mate - even to a prcd-affected dog which may be a desirable breeding prospect for other reasons. The chance of producing affected pups from such breedings depends on the certainty of test results. Again, you’ll find the specific information on certainty of test results for your dog by linking to breed specific information.

The OptiGen prcd test is done on a small sample of blood from the dog. The test analyses the specific DNA mutation causing prcd-PRA. The OptiGen test detects the mutant, abnormal gene copy and the normal gene copy. The result of the test is a genotype and allows separation of dogs into three groups: Normal/Clear (homozygous normal), Carrier (heterozygous) and Affected (homozygous mutant).

Phosphofructokinase (PFK) deficiency is an inherited disease that affects both the field trial and show lines of English Springer Spaniels. M-PFK is an enzyme required for the metabolism of glucose into useable energy. Without the PFK enzyme, some cells, such as muscle cells and red blood cells, cannot produce adequate energy for their needs. Therefore, affected dogs display the following intermittent, clinical signs: weakness, lethargy, exercise intolerance, poor performance, muscle cramps, anemia, jaundice, and dark-colored urine. Dark-colored urine, a hallmark of this disorder, usually appears after strenuous exercise or after excessive barking, panting, and heat exposure.

PFK deficiency is caused by a mutation of the gene that codes for the enzyme M-PFK. Because PFK deficiency is an autosomal recessive trait, a dog must have two copies of the mutated gene (one from each parent) to show clinical signs. A dog with one copy may be healthy but will pass the mutation to its offspring. The mutation has so far been documented in over 100 English Springer Spaniels, especially in field trial lines, but the actual prevalence of the mutation is unknown.

Researchers at the University of Pennsylvania have developed a simple, reliable test to detect the mutation that causes PFK deficiency. This test requires a DNA sample obtained from a cheek swab or blood sample.

· Clear - the dog has two normal PFK genes and does not carry the mutation. The dog will not show clinical signs and will not pass the mutation to its offspring. This dog can be used for breeding.

· Carrier - The dog is heterozygous and has one normal and one mutant gene (allele). The dog will not show any clinical signs; therefore, a carrier can be shown and used for field trials without compromising the dog's health. A carrier will pass the mutant gene to approximately half of its offspring, producing further carriers and continuing the presence of the mutant gene in the general population. Carrier animals should only be bred if they otherwise meet the health, temperament, and quality criteria for breeding; with full disclosure to the owner of the mated dog of the carrier status; with confirmation that the mated dog is not itself a carrier, as such a breeding would produce affected offspring; and with agreement between both parties to the mating that all puppies will be tested prior to placement with all puppies identified as carriers placed with a spay/neuter requirement.

· Affected - the dog has two copies of the mutant gene (allele). The dog will show intermittent clinical signs of disease and will not perform well in field trials. Further, affected dogs will pass the mutation to 100 percent of its offspring. Affected dogs should never be bred.

By testing and breeding appropriately, PFK deficiency can be rapidly eliminated from the breed. Based on the information this test provides the continued spread of this disease, the costs for diagnosis and management, and animal suffering can all be prevented.

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Now trading as Verstone Gundogs Ltd.

Last modified: February 22, 2018