Polycystic kidney disease in Persian cats: ultrasound diagnosis

Question

18-month-old male Persian cat with no clinical signs, at a pre-breeding check. Both kidneys contain multiple round, anechoic, thin-walled structures with posterior acoustic enhancement in the cortex and medulla. Transverse section of one kidney:

Transverse ultrasound section of a cat's kidney with numerous round, anechoic, thin-walled structures of varying size — Image: Kalumet · CC BY-SA 3.0, Wikimedia Commons

Which statement is correct?

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A. It is an autosomal dominant disease; relatives should be screened (PKD1 genetic test or ultrasound) and affected cats should not be bred

Correct. PKD in Persians and related breeds is caused by a dominant mutation in the PKD1 gene: a single allele is enough to have the disease. The genetic test detects that mutation at any age; ultrasound is reliable from about 10 months of age.

B. It is autosomal recessive, so healthy carriers can be bred together without risk

Inheritance is dominant: there are no healthy carriers, any cat with the mutation develops cysts, and half of its offspring will inherit it.

C. The treatment of choice is ultrasound-guided drainage of the cysts

Draining cysts does not slow the disease: cysts are multiple and refill. Treatment is that of chronic kidney disease according to IRIS stage.

D. It is the same disease as perirenal pseudocysts

Perirenal pseudocysts are fluid accumulations between the capsule and the parenchyma, without epithelium, surrounding the kidney. They are a different entity from the intraparenchymal cysts of PKD.

lightbulb Key takeaway

A simple cyst on ultrasound: anechoic, round, thin-walled and with distal acoustic enhancement. PKD can also affect the liver and its progression is variable: many cats do not develop CKD until middle or old age. For breeding, the PKD1 genetic test allows selection of clear breeding cats before ultrasound becomes reliable.

Which statement is correct?

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