Juvenile Addison’s disease (JADD) in Nova Scotia Duck Tolling Retrievers

Nova Scotia Duck Tolling Retrievers can suffer from a disorder known as Juvenile Addison’s Disease of JADD. It s a genetically inherited form of the disorder and young dogs are affected when they are typically around 8 weeks old although some NSDTRs show signs of there being something wrong when they are a year old too.

How the disorder was discovered

Researchers in the USA were successful at developing a DNA test which can identify carriers of Juvenile Addison’s disease in Nova Scotia Duck Tolling Retrievers. The condition differs from the “adult onset form of Addison’s disease because an affected Toller has what is referred to as “2 identical copies” of a certain region found in the genomes. Scientists were able to identify several markers in this specific region which meant they were able to establish whether a Toller was a carrier of the gene mutation or not through a haplotype test.

Studies have established that the gene mutation responsible for Tollers developing JADD, changes the “amino acid sequence” in essential proteins and that the mutation has not been found in any other dog breeds. With this said, more research is being carried out to find out just why some Tollers are affected by JADD whereas others are not.

Treatment of the disorder

A vet would treat a Toller puppy that’s been diagnosed as suffering from JADD with glucocorticoid and mineralocorticoid replacement therapy. However, affected puppies often suffer from other disorders at the same time which includes the following:

• Eye issues such as corneal oedema, uveitis or conjunctivitis

Mode of Inheritance

A Toller puppy would inherit the disorder as an autosomal recessive disease which in short, means they would need to inherit one mutated gene from each parent dog. However, not all affected Toller puppies that have inherited 2 copies of the gene mutation would develop JADD with research suggesting that around 75% of them would do so.

Test Results Explained

The test results for Tollers suspected of suffering from JADD are as follows:

• JADD Probable N/N:This establishes that a Toller has 2 normal copies of the JADD region and will not develop the specific form of juvenile onset Addison’s Disease which is identified by the test. However, it is worth noting that there are other forms of Addison’s Disease seen in the Nova Scotia Duck Tolling Retriever. This establishes that a dog would only transmit the normal gene to puppies and as such would not transmit this form of the disorder to offspring
• JADD Probable N/A:This establishes that a Toller has 1 mutated copy of the JADD region and is therefore a carrier. It is worth noting that no Tollers that are carriers have been reported as suffering from juvenile onset Addison’s Disease. With this said, they can transmit either a normal copy of the region or an abnormal copy to puppies
• JADD Probable A/A:This establishes a Toller has 2 mutated copies of the JADD region and therefore there is a 75% chance of them developing Addison’s Disease by the time they are 12 months old