Familial nephropathy (Cocker spaniel type) is an inherited disorder of the kidneys affecting dogs. Dogs with this disease usually start showing symptoms of chronic kidney disease between 6 months and 2 years of age. Normally protein is not present in the urine, but in affected dogs there is a defect that allows protein from the blood to be filtered by the kidneys and lost in the urine. Abnormal amounts of protein can be detected in the urine as early as five months of age. Symptoms of chronic kidney disease include excessive thirst and urination, vomiting, inappetence, weight loss, weakness and fatigue. If drinking excessively, some dogs may also inappropriately urinate in the house or in a crate. Affected dogs eventually die of chronic kidney failure within a year.
Breed-Specific Information for the Cocker Spaniel
Cocker Spaniel is included as a breed susceptible to familial nephropathy (cocker spaniel type) because of its close relatedness to the English cocker spaniel breed, which is known to develop this disease due to Mutation of the COL4A4 gene. The frequency of the causal mutation in the general cocker spaniel population is unknown.
Genetic testing of the COL4A4 gene in cocker spaniels will reliably determine whether a dog is a genetic Carrier of familial nephropathy (cocker spaniel type). Familial nephropathy (cocker spaniel type) is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the COL4A4 gene mutation. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Cocker Spaniels that are not carriers of the mutation have no increased risk of having affected pups.
There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.
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