Renal dysplasia is an inherited disease that is caused by an abnormal (incomplete) development of the kidneys before the puppy is born. In some cases, the incomplete development may also affect other parts of the urinary system such that one kidney may be missing (renal aplasia), much smaller than normal (renal hypoplasia), or the connections (ureters) are incorrectly formed between the kidneys and the bladder (ectopic ureters). Some affected Cairn Terriers may also be missing a kidney. 
 
Clinical signs of disease can be seen as young as 8 weeks of age or may not be apparent until later in life at several years of age. Typical clinical signs consist of increased urination and drinking, vomiting, depression, loss of appetite, and weight loss. Once affected dogs begin to show clinical signs, researchers estimate that less than 25% of the kidney function is left. There is no curative treatment other than performing a kidney transplant, which is not always successful in dogs and is extremely costly (upwards of $25,000). The severity of this disease makes it all the more important that we find the underlying genetic cause to eliminate this disease from our breeding programs.

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