Juvenile Renal Dysplasia- Facts sheet

What is JRD?
Juvenile renal dysplasia (JRD) is an important category of kidney diseases in dogs. Dysplasia is defined as abnormal growth or development of cells or organs. In the case of JRD, the kidneys fail to develop properly in the womb. At birth immature structures consisting of undifferentiated fetal cells or tissue types are found in the kidney and are persistent throughout the life of the animal. As a result, some dogs develop serious disease as puppies and usually die before a year of age.
Others become ill later in life. Treatment may help these dogs for a while but they will have shortened life spans because of the disease.
Most dogs with the mutation don't develop disease at all, but for those who do, it is a serious and life-threatening situation.

What to look for in young animals
Some of the early signs of JRD in puppies over 10 weeks may include excessive drinking and urination and pale (dilute) urine. Often there are problems with housebreaking.

*IMPORTANT*
Most animals that harbor one or two copies of this mutation will have some minor defects in the kidney that can only be seen on biopsy. This does NOT affect the overall health of the animal. Their kidneys function normally and appear normal on the gross scale. Some may be biopsy negative. Any of these cases, can however, produce JRD affected progeny.

When clinical cases do arise, from severely under-developed kidneys, the results can be devastating and can result in end stage renal failure.
How is JRD inherited?

JRD is inherited as "dominant with incomplete penetrance. This means that animals with one or two copies of the mutation are at risk for developing the disease and/or passing this on to their progeny. The risk in the case of JRD is low meaning that most carriers or homozygotes for the mutation are sub-clinical.

What does the genetic test tell you?
The DNA test results are reported as follows:
a) Carrier - (one copy of the JRD mutation)
b) Homozygous mutant allele = Homozygote (two copies of the JRD mutation)
c) Clear - No copies of the JRD mutation are present.

With a) or b) results the animal is potentially affected by JRD or may be clinically normal. However, clinically normal animals can pass the disease on to their offspring.

For Breeding decisions and Outcomes

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Down the Road
Your ultimate goal is to breed only clear to clear. Through effective use of the JRD test and careful breeding decisions you can eliminate JRD from your kennel without having compromised the gene pool. This will involve breeding to carrier and clear animals in the process.