Protein-losing Nephropathy in Dogs: Causes, Symptoms & Testing

Protein-losing nephropathy (PLN) is a hereditary kidney condition affecting dogs, particularly the soft coated wheaten terrier puppies. Large breeds like the Bernese mountain dog, Golden retriever, and Labrador retriever also face higher risks.

The disorder typically develops in adult dogs aged between two to six years old. Sometimes, affected dogs may unknowingly be used for breeding before symptoms appear, which unfortunately helps spread the condition within breeds. Thankfully, health testing protocols exist for soft coated wheaten terriers, helping owners assess their dogs' risk and make responsible breeding decisions.

What is protein-losing nephropathy?

Protein-losing nephropathy describes a collection of kidney diseases that damage the glomeruli—tiny filtering units within the kidney responsible for retaining protein in the bloodstream. When these structures are impaired, excessive protein leaks into the urine, causing protein loss from the body.

This protein loss leads to systemic health problems, as protein is vital for many bodily functions. Causes of PLN include underlying issues like amyloidosis, kidney inflammation and infections, kidney failure, and chronic kidney disease.

Which dogs are most at risk of PLN?

The soft coated wheaten terrier is the breed most commonly associated with protein-losing nephropathy, making testing especially critical. Large dog breeds such as the Bernese mountain dog puppies, Golden retrievers, and Labradors are also known to be affected more frequently than smaller breeds. The condition tends to be slightly more common in females than males.

Signs and symptoms to watch for

Early symptoms of PLN are often subtle and can be easily overlooked, as they are general and may mimic other common ailments. However, early recognition is critical to managing the condition effectively.

• Loss of appetite or refusal to eat
• Regular vomiting, sometimes after meals
• Weight loss without obvious cause
• Behavioural changes, such as aggression or confusion
• Swelling around the abdomen and limbs due to fluid retention
• Increased thirst and drinking
• Reduced urination frequency despite drinking more water
• Heightened sensitivities or allergic-like reactions to certain foods
• Chronic itching and skin irritation across the body

Any combination of these signs warrants a prompt veterinary consultation to diagnose PLN or rule out other conditions. Since PLN progresses over months or years, early detection improves management outcomes.

How is protein-losing nephropathy inherited?

In soft coated wheaten terriers, PLN is inherited through an autosomal gene defect passed from both parents. Dogs inheriting one copy of the faulty gene are at moderate risk, while those inheriting two copies have a higher chance of developing symptoms.

Health testing: a vital tool for prevention

Responsible breeders and owners should use genetic testing available for soft coated wheaten terriers to determine their dog’s PLN status before planning to breed. Testing involves collecting a blood sample or buccal swab that is sent to an accredited laboratory.

Both prospective sire and dam should be tested, even if they appear healthy, as the disease can develop later in adulthood. Asking breeders for health test results before purchasing puppies is also strongly advised to help reduce the condition’s prevalence.

Overall, health testing combined with informed breeding decisions helps raise healthier generations of dogs and reduces the spread of protein-losing nephropathy.

How is protein-losing nephropathy medically managed?

While there is no definitive cure for PLN, early diagnosis allows effective management that can maintain quality of life for affected dogs. Treatment usually includes medications such as ACE inhibitors (enalapril or benazepril) to reduce protein loss, blood pressure control, and specialised diets with restricted but high-quality protein.

Regular veterinary monitoring is essential to check kidney function and adjust therapies as needed. Additionally, some dogs may benefit from low-dose aspirin to reduce the risk of blood clots.

What should you do if you suspect PLN?

If your dog shows any symptoms suggestive of protein-losing nephropathy, arrange a veterinary appointment promptly. Your vet will perform urine and blood tests to detect protein loss and assess kidney health. Early diagnosis and intervention improve the outlook for dogs with this condition.

In summary, protein-losing nephropathy is a serious hereditary kidney disorder primarily affecting soft coated wheaten terriers and some large breeds. Awareness of symptoms, responsible health testing, informed breeding choices, and early veterinary management are key to protecting your dog’s wellbeing.