What is Polycystic Kidney Disease?

Polycystic Kidney Disease (PKD) is a hereditary condition in which fluid-filled cysts develop within the kidneys. These cysts are present from birth and grow slowly over time, progressively replacing normal kidney tissue and impairing kidney function. Eventually, PKD can lead to chronic kidney disease (CKD) and kidney failure.

PKD is inherited as an autosomal dominant trait — a cat only needs one copy of the defective gene to be affected. This means that if one parent carries the gene, approximately 50% of offspring will inherit the condition.

Affected Breeds

PKD is most prevalent in:

  • Persian cats (estimated 36–49% prevalence in some studies)
  • Exotic Shorthair
  • Himalayan
  • British Shorthair
  • Scottish Fold
  • Selkirk Rex
  • Any breed with Persian ancestry

The condition can also rarely occur in other breeds and mixed-breed cats.

Symptoms

PKD is a slowly progressive disease. Most cats show no symptoms until middle age (typically 7–10 years), when enough kidney tissue has been replaced by cysts:

  • Increased thirst and urination (polyuria/polydipsia)
  • Weight loss
  • Decreased appetite
  • Lethargy
  • Vomiting
  • Poor coat quality
  • In advanced cases: severe kidney failure

Some cats are diagnosed incidentally during routine health screenings, allowing for earlier management.

Diagnosis

Ultrasound

The gold standard for diagnosing PKD. Cysts can be detected as early as 10 months of age in many cases, though some cysts may not be visible until later. An experienced ultrasonographer can identify cysts with high accuracy.

Genetic (DNA) Testing

A DNA test is available for the specific PKD1 gene mutation found in Persians and related breeds. This test:

  • Can be performed at any age (even in kittens)
  • Uses a cheek swab or blood sample
  • Gives a definitive positive or negative result
  • Is the recommended screening tool for breeders

Why Screening Matters for Breeders

PKD screening is essential for responsible breeding:

  • All breeding cats of susceptible breeds should be tested (DNA test or ultrasound)
  • PKD-positive cats should be removed from breeding programs to prevent passing the gene to offspring
  • Thanks to widespread screening, the prevalence of PKD has decreased significantly in well-managed breeding programs
  • Reputable breed registries and catteries require PKD-negative status for breeding cats

Treatment and Management

There is no cure for PKD. Treatment focuses on managing chronic kidney disease as it develops:

  • Renal diet: Specialized low-phosphorus, moderate-protein food
  • Fluid therapy: Subcutaneous fluids to maintain hydration
  • Phosphorus binders: To control blood phosphorus levels
  • Anti-nausea medication: For appetite support
  • Blood pressure monitoring: Hypertension is common with kidney disease
  • Regular blood work: To monitor kidney values (BUN, creatinine, SDMA)

With early detection and proactive management, many PKD cats can maintain a good quality of life for years.

For Adopters

If you are adopting a Persian or related breed:

  • Ask the breeder for PKD testing documentation
  • Reputable breeders will have DNA-tested their breeding cats
  • If adopting an adult cat of a susceptible breed, discuss screening with your veterinarian
Canada Flag