Autosomal Recessive Hereditary Nephropathy, Familial Nephropathy, ARHN

Progression of the disease is typically rapid, and affected dogs may exhibit muscle wasting, abnormal accumulation of fluids in tissue (usually first observed as edema in the limbs), and excessive thirst and urination. PLN dogs are also at high risk of clotting problems due to a loss of clotting protein (Antithrombin III). End-stage renal disease may present with vomiting, poor appetite, and lethargy, and most often occurs at about 12 months of age but can occur as early as six months or as late as 24 months of age.

Affected dogs appear completely healthy as puppies, developing persistent protein in the urine (proteinuria) as the first symptom of the disease. The onset of proteinuria most often is between four to six months of age but can be as early as between two to three months or as late as between six to eight months of age.

Diagnosis is made based on clinical history, physical examination, laboratory values, and genetic testing. Proteinuria, increasing azotemia (BUN and/or creatinine), and possibly low blood protein may be noted. Additional tests, including blood pressure and abdominal ultrasound may be recommended based on a dog’s clinical signs.

There is no cure for ARHN; all currently available treatments are symptomatic or supportive in nature. Current therapies are aimed at reducing the protein load on the kidney, fighting the toxic effects of protein wasting, maintaining hydration, and addressing an elevation in blood pressure, if present.

Talk to your vet about your dog’s nephropathy result so you can work together to plan ongoing care and monitoring.

Schedule regular checkups and lab testing as recommended to monitor kidney function and detect any changes early.

Your vet may recommend a kidney-supportive diet and supplements to help maintain kidney health.

Watch for changes in drinking or urination habits, such as increased thirst, accidents, or changes in urine volume, and contact your vet if you notice any of these signs.

It is important to note that Protein Losing Nephropathy (PLN) can be secondary to a variety of diseases. Even dogs without risk from this variant can develop PLN, and your veterinarian will need to rule out other causes of PLN with a series of diagnostic tests.

Penetrance: Hereditary Nephropathy is recessive, that is, a dog requires two copies of the variant to show signs of the disease from the variant. This variant was first described in the English Springer Spaniel.

Gene

COL4A4 Exon 30

Inheritance type

recessive

Clinical category

Urinary

Citations

1. Nowend et al 2012

• English Springer Spaniel