Disease overview

Rod-cone dysplasia is an Cystinuria is an inherited metabolic disease that is relatively common in dogs and rare in cats. It is a renal transport disease involving cystine and the dibasic amino acids ornithine, lysine, and arginine, collectively known as COLA. In healthy animals, the small intestine is responsible for absorption of these amino acids, followed by filtration by the glomerulus and, eventually, almost complete resorption in the proximal convoluted tubule. In cystinuria, where tubular resorption is decreased, an increased amount of the COLA amino acids appear in the urine, but it is cystine in particular that leads to complications. Its increased amount and low solubility in urine can cause the formation of cystine crystals and uroliths in the urinary tract. This can eventaully lead to renal failure, among other complications. onset retinopathy characterized by the primary loss of cone function, accompanied by variable degrees of reduced rod function. Typically, loss of central vision preceeds the loss of peripheral vision. It is also suggested that photoreceptor cell development is delayed in cats with Rdy and that these cells' degeneration follows soon after their differentiation. Rdy was first described in Abyssinian cats, although other purebred and mixed-breed cats can also have the causative mutation.

Gene name

SLC3A1 (associated with Cystinuria type IA), SLC7A9 (associated with Cystinuria type B)

Inheritance

Likely autosomal recessive

Signs and symptoms

Clinical signs of cystinuria include elevated levels of cystine in the urine, uroliths in the kidneys, bladder, and urethra, pain upon urination. In some cases, this condition can cause a urinary blockage where no urine will be passed. This condition is considered an emergency.

How is it diagnosed

Diangosis is made after urinalysis, revealing high levels of cystine in the urine.

Breeds at higher risk

Current data does not indicate that specific breeds are at a higher risk.

Citations

https://pubmed.ncbi.nlm.nih.gov/25417848/ https://pubmed.ncbi.nlm.nih.gov/27404572/

Disclaimer

Disease diagnosis and treatment should always be performed by a veterinarian. The following information is for educational purposes only.