Familial Nephropathy (FN)

Description

Familial Nephropathy (FN) is a fatal kidney disease that occurs in English Cocker Spaniels. FN is an autosomal recessive disease. Autosomal recessive diseases are a disease that can be passed from either parent and require two copies of the gene to show symptoms.

Affected dogs are born with an abnormal structure in the walls of their kidneys and are unable to remove waste products from their blood through urination. COL4A3 and COL4A4 are two genes associated with the formation of peptides (protein) in the walls. When these genes are mutated, it interrupts the production of the proteins. This interruption disrupts the integrity of the capillary walls and causes progressive renal damage in the dog.

FN is a juvenile-onset disease, which means that it typically occurs between the ages of 6 months to 2 years old. The progression of the disease varies in affected dogs. Some individuals may develop chronic renal failure faster than others, leading to the failing of both kidneys and eventually, death.

Early signs of FN include:

• excessive water consumption
• excessive urine volume
• weight loss
• poor quality fur coat
• reduced appetite
• vomiting

High levels of protein in the urine are often linked to FN in English Cocker Spaniels.

Because FN is a recessive disorder, a dog must have two copies of the mutation in order for the disease to manifest. This means that a dog can have one copy of the mutation and not experience any signs or symptoms of FN. This dog would be known as a carrier. The carrier can then pass on either the normal gene or the mutated gene to any offspring. If two carriers are bred, there is a 25% per puppy that they will develop symptoms of FN.