Change of Renal Cystic Fluid in a Cat with Feline Polycystic Kidney Disease Caused by PKD-1 Gene Mutation

Abstract

A four-year-old castrated male mixed-breed cat suspected of hydronephrosis was referred to our Veterinary Teaching Hospital. Abdominal radiography revealed enlarged kidneys, and renal ultrasonography detected anechoic cysts of various sizes in both kidneys. Genetic testing using the PCR-RFLP method identified a mutation (3284C→A) in the PKD1 gene. The cat was therefore diagnosed with autosomal dominantly-inherited polycystic kidney disease. At initial presentation to our Veterinary Teaching Hospital, hematological examination showed azotemia and hyperphosphatemia. The cat received peritoneal dialysis for a short duration. Subsequently, it was treated by fluid therapy and prescription diet for renal disease, and monitored for about one year. An analysis of cystic fluid collected from several cysts of both kidneys showed persistently high concentrations of chloride anion and sodium cation. This finding was observed throughout the follow-up period. In addition, the concentration of N-acetyl-β-D-glucosaminidase (NAG) and the value of NAG isozyme B tended to increase with the progression of renal failure.