Cocker Spaniel Club of the ACT
 

Familial Nephropathy (FN)

Information has been sourced from https://www.ufaw.org.uk/dogs/cocker-spaniel---familial-nephropathy

1. Brief description

Familial nephropathy describes a disease of the kidneys that is inherited in Cocker spaniels and is one in which young dogs suffer from early-onset kidney failure. Dogs with the condition are born with an abnormal structure in the walls of the kidney tubules, which affects the dog’s ability to remove waste products from the blood and to produce urine. The walls of the kidney tubules are excessively leaky resulting in abnormally high levels of protein passing from the blood into the urine, and this leads to further damage to the kidney tubule walls. Familial nephropathy is progressive and ultimately fatal, since the damage to the kidneys is irreparable and eventually the kidneys cease to function. The condition has a rapid onset and affects young dogs, usually between 6 months and 2 years of age.

The clinical signs of familial nephropathy are usually the same as those observed generally for chronic kidney failure of any cause, and include excessive thirst and urination, loss of appetite, lethargy, vomiting, anorexia, halitosis (bad breath), poor coat quality and pale mucous membranes. These signs are non-specific and so an early diagnosis can be difficult to make.

2. Intensity of welfare impact     

Familial nephropathy affects young dogs and the disease is progressive, and ultimately fatal for dogs. Affected dogs experience loss of appetite, vomiting, nausea and abdominal pain as a result of the kidneys lack of ability to excrete waste products.

There is no cure for familial nephropathy, but diets formulated for dogs with renal failure, or administration of an angiotensin converting enzyme inhibitor can reduce the clinical signs.

3. Duration of welfare impact

Most dogs with familial nephropathy have abnormally high levels of proteins in the urine (proteinuria) before one year of age, and will develop kidney failure between 6 months and 2 years of age. However, the rate of disease progression varies between individuals, and some dogs can become seriously ill at a more rapid rate than others.

4. Number of animals affected 

To date, there are no published data available for the number of dogs affected by this condition. Familial nephropathy has been reported to affect 11% of English Cocker spaniels in Europe (https://www.antagene.com/en/no/familial-nephropathy-english-cocker-spaniel-breed) but this statistic should be used cautiously since no supporting evidence is provided.

5. Diagnosis

The clinical signs of familial nephropathy are difficult to distinguish from those associated with kidney damage caused by other diseases, and an early diagnosis may be difficult to make. In young dogs, persistently high levels of protein in the urine is most often due to familial nephropathy and therefore the best diagnostic tool to start with is urine sampling. A biopsy will be needed to confirm diagnosis.

6. Genetics

Familial nephropathy is a simple inherited trait which is autosomal (ie not carried on the sex chromosomes thus affects both males and females) and recessive. This means a dog needs to inherit two copies of the mutated gene for it to be affected by the disease. If a dog only has one copy of the mutation, the dog will not be affected but is a carrier, and may pass on the mutated gene to some of their offspring if the other parent is affected or a carrier also.

7. How do you know if an animal is a carrier or likely to become affected?

DNA testing, can be used to identify the mutation for familial nephropathy in Cocker spaniels, with good reliability. DNA can be analysed from either blood samples or mouth swabs. The test can identify dogs that are affected, carriers and those clear of the condition.

8. Methods and prospects for elimination of the problem 

Efforts are ongoing to eliminate the disease from the Cocker spaniel breed using DNA testing and careful breeding practices. Responsible breeders will only to mate only two clear dogs, or one clear and one carrier dog, to produce unaffected offspring.